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Purpose: Post-operative infectious complication (IC) is a well-known negative prognostic factor, while showing neoadjuvant chemotherapy (NAC) may cancel out the negative influence of IC. This analysis compared the clinical impacts of IC according to the presence or absence of NAC in gastric cancer patients enrolled in the phase III clinical trial (JCOG0501) which compared upfront surgery (arm A) and NAC followed by surgery (arm B) in type 4 and large type 3 gastric cancer., Methods: The subjects were 224 patients who underwent R0 resection out of 316 patients enrolled in JCOG0501. The prognoses of the patients with or without ICs in each arm were investigated by univariable and multivariable Cox regression analyses., Results: There were 21 (20.0%) IC occurrences in arm A and 15 (12.6%) in arm B. In arm A, the overall survival (OS) of patients with ICs was slightly worse than those without IC (3-year OS, 57.1% in patients with ICs, 79.8% in those without ICs; adjusted hazard ratio (95% confidence interval), 1.292 (0.655-2.546)). In arm B, patients with ICs showed a trend of better survival than those without ICs (3-year OS, 80.0% in patients with IC, 74.0% in those without IC; adjusted hazard ratio, 0.573 (0.226-1.456))., Conclusion: This study could not indicate the negative prognostic influence of ICs in gastric cancer patients receiving NAC, which might be canceled by NAC. To build exact evidence, further investigation with prospective and large numbers of data might be expected., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: This randomized phase II study explored the superiority of trastuzumab plus S-1 plus cisplatin (SP) over SP alone as neoadjuvant chemotherapy (NAC) for HER2-positive resectable gastric cancer with extensive lymph node metastasis., Methods: Eligible patients with HER2-positive gastric or esophagogastric junction cancer and extensive lymph node metastasis were randomized to receive three or four courses of preoperative chemotherapy with SP (arm A) or SP plus trastuzumab (arm B). Following gastrectomy, adjuvant chemotherapy with S-1 was administered for 1 year in both arms. The primary endpoint was overall survival, and the sample size was 130 patients in total. The trial is registered with the Japan Registry of Clinical Trials, jRCTs031180006., Results: This report elucidates the early endpoints, including pathological findings and safety. The study was terminated early due to slow patient accruals. In total, 46 patients were allocated to arm A (n = 22) and arm B (n = 24). NAC was completed in 20 patients (91%) in arm A and 23 patients (96%) in arm B, with similar incidences of grade 3-4 hematological and non-hematological adverse events. Objective response rates were 50% in arm A and 84% in arm B (p = 0·065). %R0 resection rates were 91% and 92%, and pathological response rates (≥ grade 1b in Japanese classification) were 23% and 50% (p = 0·072) in resected patients, respectively., Conclusions: Trastuzumab can be safely added to platinum-containing doublet chemotherapy as NAC, and it has the potential to contribute to higher antitumor activity against locally advanced, HER2-positive gastric or esophagogastric junction cancer with extensive nodal metastasis., (© 2024. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: The prognosis for marginally resectable gastric cancer with extensive lymph node metastasis (ELM) remains unfavorable, even after R0 resection. To assess the safety and efficacy of preoperative docetaxel, oxaliplatin, and S-1 (DOS), we conducted a multicenter phase II trial., Methods: Eligibility criteria included histologically proven HER2-negative gastric adenocarcinoma with bulky nodal (bulky N) involvement around major branched arteries or para-aortic node (PAN) metastases. Patients received three cycles of docetaxel (40 mg/m 2 , day 1), oxaliplatin (100 mg/m 2 , day 1), and S-1 (80-120 mg/body, days 1-14), followed by gastrectomy with D2 plus PAN dissection. Subsequently, patients underwent postoperative chemotherapy with S-1 for 1 year. The primary endpoint was major (grade ≥ 2a) pathological response rate (pRR) according to the Japanese Classification of Gastric Carcinoma criteria., Results: Between October 2018 and March 2022, 47 patients (bulky N, 20; PAN, 17; both, 10) were enrolled in the trial. One patient was ineligible. Another declined any protocol treatments before initiation. Among the 45 eligible patients who initiated DOS chemotherapy, 44 (98%) completed 3 cycles and 42 (93%) underwent R0 resection. Major pRR and pathological complete response rates among the 46 eligible patients, including the patient who declined treatment, were 57% (26/46) and 24% (11/46), respectively. Common grade 3 or 4 toxicities were neutropenia (24%), anorexia (16%), febrile neutropenia (9%), and diarrhea (9%). No treatment-related deaths occurred., Conclusions: Preoperative chemotherapy with DOS yielded favorable pathological responses with an acceptable toxicity profile. This multimodal approach is highly promising for treating gastric cancer with ELM., (© 2024. The Author(s).)

Background: Abdominal surgical infectious complications (ASIC) after gastrectomy for gastric cancer impair patients' survival and quality of life. JCOG0912 was conducted to compare laparoscopy-assisted distal gastrectomy with open distal gastrectomy for clinical stage IA or IB gastric cancer. The present study aimed to identify risk factors for ASIC using prospectively collected data., Methods: We performed a post-hoc analysis of the risk factors for ASIC using the dataset from JCOG0912. All complications were evaluated according to the Clavien-Dindo classification (CD). ASIC was defined as CD grade I or higher anastomotic leakage, pancreatic fistula, abdominal abscess, and wound infection. Analyses were performed using the logistic regression model for univariable and multivariable analyses., Results: A total of 910 patients were included (median age, 63 years; male sex, 61 %). Among them, ASIC occurred in 5.8 % of patients. In the univariable analysis, male sex (odds ratio [OR] 2.855, P = 0.003), diabetes (OR 2.565, P = 0.029), and Roux-en-Y (R-Y) reconstruction (vs. Billroth Ⅰ, OR 2.707, P = 0.002) were significant risk factors for ASIC. In the multivariable analysis, male sex (OR 2.364, P = 0.028) and R-Y reconstruction (vs. Billroth Ⅰ, OR 2.310, P = 0.015) were independent risk factors for ASIC., Conclusions: Male sex and R-Y reconstruction were risk factors for ASIC after distal gastrectomy. Therefore, when performing surgery on male patients or when R-Y reconstruction is selected after gastrectomy for gastric cancer, surgeons should pay special attention to prevent ASIC., (© 2024 Published by Elsevier Ltd.)

Treatment strategies for oesophagogastric junction adenocarcinoma have not been standardized despite its poor prognosis due to differences in the incidence rates between Western countries and Asia. This randomized Phase II/III trial was initiated in June 2023 to determine which neoadjuvant chemotherapy regimen, docetaxel, oxaliplatin and S-1 or fluorouracil, oxaliplatin and docetaxel, is a more promising treatment in Phase II and confirm the superiority of neoadjuvant chemotherapy with docetaxel, oxaliplatin and S-1 or fluorouracil, oxaliplatin and docetaxel followed by surgery and postoperative chemotherapy over upfront surgery and postoperative chemotherapy in terms of overall survival in patients with Clinical Stage III or IVA oesophagogastric junction adenocarcinoma in Phase III. A total of 460 patients, including 150 patients in Phase II and 310 patients in Phase III, are planned to be enrolled from 85 hospitals in Japan over 5 years. This trial has been registered in the Japan Registry of Clinical Trials as jRCTs031230182 (https://jrct.niph.go.jp/latest-detail/jRCTs031230182)., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Recent studies have revealed that sarcopenia is associated with postoperative complications and poor prognosis. Although neoadjuvant chemotherapy is a promising treatment for gastric cancer, its toxicity may lead to the loss of skeletal muscle mass. This study investigates the changes in skeletal muscle mass during neoadjuvant chemotherapy and its clinical impact on patients with locally advanced gastric cancer., Methods: Fifty patients who completed two courses of neoadjuvant chemotherapy followed by surgery were included. Skeletal muscle mass was measured using computed tomography images before and after chemotherapy. The proportion of skeletal muscle mass change (%SMC) during neoadjuvant chemotherapy and its cutoff value was explored using the receiver operating characteristic for the overall survival of patients undergoing R0 resection. Risk factors of skeletal muscle mass loss were also evaluated., Results: Overall, 64% of patients had skeletal muscle mass loss during neoadjuvant chemotherapy (median %SMC -3.4%; range: -18.9% to 10.3%). Multivariable analysis identified older age (≥70 years) as an independent predictor of skeletal muscle mass loss (mean [95% confidence interval]: -4.70% [-8.83 to -0.58], p = 0.026). Among 43 patients undergoing R0 resection, %SMC <-6.9% was an independent poor prognostic factor for overall survival (hazard ratio, 11.53; 95% confidence interval, 2.78-47.80) and relapse-free survival (hazard ratio 4.54, 95% confidence interval 1.50-13.81)., Conclusions: Skeletal muscle mass loss occurs frequently during neoadjuvant chemotherapy for locally advanced gastric cancer and could adversely affect survival outcomes., (© 2023 International Society of Surgery/Société Internationale de Chirurgie (ISS/SIC).)

Background: Postoperative adjuvant chemotherapy with S-1 for 1 year (corresponding to eight courses) is the standard treatment for pathological stage II gastric cancer. The phase III trial (JCOG1104) investigating the non-inferiority of four courses of S-1 to eight courses was terminated due to futility at the first interim analysis. To confirm the primary results, we reported the results after a 5-years follow-up in JCOG1104., Methods: Patients histologically diagnosed with stage II gastric cancer after radical gastrectomy were randomly assigned to receive S-1 for eight or four courses. In detail, 80 mg/m 2 /day S-1 was administered for 4 weeks followed by a 2-week rest as a single course., Results: Between February 16, 2012, and March 19, 2017, 590 patients were enrolled and randomly assigned to 8-course (295 patients) and 4-course (295 patients) regimens. After a 5-years follow-up, the relapse-free survival at 3 years was 92.2% for the 8-course arm and 90.1% for the 4-course arm, and that at 5 years was 87.7% for the 8-course arm and 85.6% for the 4-course arm (hazard ratio 1.265, 95% CI 0.846-1.892). The overall survival at 3 years was 94.9% for the 8-course arm, 93.2% for the 4-course arm, and that at 5 years was 89.7% for the 8-course arm, and 88.6% for the 4-course arm (HR 1.121, 95% CI 0.719-1.749)., Conclusions: The survival of the four-course arm was slightly but consistently inferior to that of the eight-course arm. Eight-course S-1 should thus remain the standard adjuvant chemotherapy for pathological stage II gastric cancer., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: A previous report confirmed the safety of laparoscopy-assisted total and proximal gastrectomies (LATG and LAPG) (JCOG1401). This report demonstrates the 5-year relapse-free survival (RFS) and overall survival (OS) after long-term follow-up to confirm the efficacy of these surgical methods as key secondary endpoints for cStage I gastric cancer., Methods: This study enrolled patients who had histologically proven gastric adenocarcinoma and were diagnosed with clinical T1N0, T1N(+), or T2N0 tumors according to the 14th edition of the Japanese Classification of Gastric Carcinoma (3rd English edition)., Results: Between April 2015 and February 2017, 246 patients were enrolled, although one patient was excluded because of misregistration. Meticulous follow-up was continued for > 5 years for each patient, and the data were analyzed in March 2022. The 5-year RFS was 90.0% (95% confidence interval [CI] 85.5-93.2%), and the 5-year OS was 91.2% (95% CI 86.9-94.2%) in all enrolled patients. Grade 3 or 4 late postoperative complications were detected in 12.7% of patients., Conclusions: This single-arm study showed that the long-term outcomes of LATG/LAPG for cStage I gastric cancer were acceptable, which is considered one of the standard treatments when performed by experienced surgeons. Trail registration UMIN000017155 ( http://www.umin.ac.jp/ctr/ )., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: Laparoscopic gastrectomy (LG) is considered a standard treatment for clinical stage I gastric cancer. Nevertheless, LG has some drawbacks, such as motion restriction and difficulties in spatial perception. Robot-assisted gastrectomy (RG) overcomes these drawbacks by using articulated forceps, tremor-filtering capability, and high-resolution three-dimensional imaging, and it is expected to enable more precise and safer procedures than LG for gastric cancer. However, robust evidence based on a large-scale randomized study is lacking., Methods: We are performing a randomized controlled phase III study to investigate the superiority of RG over LG for clinical T1-2N0-2 gastric cancer in terms of safety. In total, 1,040 patients are planned to be enrolled from 46 Japanese institutions over 5 years. The primary endpoint is the incidence of postoperative intra-abdominal infectious complications, including anastomotic leakage, pancreatic fistula, and intra-abdominal abscess of Clavien-Dindo (CD) grade ≥ II. The secondary endpoints are the incidence of all CD grade ≥ II and ≥ IIIA postoperative complications, the incidence of CD grade ≥ IIIA postoperative intra-abdominal infectious complications, relapse-free survival, overall survival, the proportion of RG completion, the proportion of LG completion, the proportion of conversion to open surgery, the proportion of operation-related death, and short-term surgical outcomes. The Japan Clinical Oncology Group Protocol Review Committee approved this study protocol in January 2020. Approval from the institutional review board was obtained before starting patient enrollment in each institution. Patient enrollment began in March 2020. We revised the protocol to expand the eligibility criteria to T1-4aN0-3 in July 2022 based on the results of randomized trials of LG demonstrating non-inferiority of LG to open surgery for survival outcomes in advanced gastric cancer., Discussion: This is the first multicenter randomized controlled trial to confirm the superiority of RG over LG in terms of safety. This study will demonstrate whether RG is superior for gastric cancer., Trial Registration: The protocol of JCOG1907 was registered in the UMIN Clinical Trials Registry as UMIN000039825 ( http://www.umin.ac.jp/ctr/index.htm ). Date of Registration: March 16, 2020. Date of First Participant Enrollment: April 1, 2020., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Macroscopic type 4 and large type 3 gastric cancer, mostly overlapping with scirrhous or linitis plastica type, exhibit a highly invasive nature and show unfavorable prognosis after curative surgery, even with adjuvant chemotherapy. A randomized phase III trial (JCOG0501) failed to demonstrate a survival advantage of neoadjuvant chemotherapy with S-1 plus cisplatin for this population. The current authors initiated a randomized phase II study comparing neoadjuvant chemotherapy with 5-fluorouracil/oxaliplatin/docetaxel versus docetaxel/oxaliplatin/S-1 for type 4 and large type 3 gastric cancer. 76 patients are planned to be enrolled over two years. The primary end point is the proportion of patients with a pathological response (grade 1b or higher) and secondary end points include overall survival and adverse events. Clinical Trial Registration : jRCTs031230231 (rctportal.niph.go.jp).

Objectives: The multi-institutional, single-arm, confirmatory trial JCOG0607 showed excellent efficacy of endoscopic submucosal dissection (ESD) for the expanded indication of intramucosal intestinal-type early gastric cancer (EGC), which consists of two groups: lesions >2 cm if clinical finding of ulcer (cUL)-negative, or those ≤3 cm if cUL-positive because of the expected low risk of lymph node metastasis. However, the proportion of noncurative resections (NCR) requiring additional surgery was high (32.4%). This post hoc analysis aimed to explore the clinical factors associated with NCR., Methods: As the expanded indication includes two different groups, we explored the clinical factors associated with NCR separately in cUL-negative (>2 cm) and cUL-positive (≤3 cm) groups using the log-linear model., Results: Two hundred and sixty cUL-negative and 206 cUL-positive EGCs were analyzed. The proportions of NCR were 33.8% in the cUL-negative group and 29.6% in the cUL-positive group. A multivariable analysis demonstrated that moderately differentiated predominant histology diagnosed in pretreatment biopsy (risk ratio [RR] 1.93, 95% confidence interval [CI] 1.34-2.77, P < 0.001) and lesion in the upper stomach (RR 1.75, 95% CI 1.03-2.96, P = 0.038) in the cUL-negative EGCs, and tumor size >2 cm (RR 1.78, 95% CI 1.22-2.58, P = 0.003) and female sex (RR 1.62, 95% CI 1.07-2.44, P = 0.021) in the cUL-positive EGCs were independent factors associated with NCR., Conclusions: Clinical risk factors associated with NCR were different between cUL-negative and cUL-positive EGCs. To avoid NCR, we need to take these factors into account when deciding expanded indications for ESD., (© 2022 Japan Gastroenterological Endoscopy Society.)

Background: Peritoneal, lymph node, and hematogenous recurrence patterns are common after potentially curative surgery for gastric cancer. However, clinicopathological characteristics associated with each recurrence type have rarely been comprehensively reported among patients who received a unified treatment strategy and follow-up protocol. Understanding these recurrence patterns would help with early detection of recurrence and a personalized follow-up plan. We investigated the initial recurrence patterns after curative gastrectomy using data from the randomized clinical JCOG1001 trial., Methods: Of 1204 patients enrolled in JCOG1001, 932 pStage II/III patients were included. Initial recurrence dates and patterns were recorded by attending physicians according to the protocol. Risk factors for hematogenous, lymph node, and peritoneal recurrence were determined by univariable and multivariable analyses using the Fine-Gray model., Results: Overall, 253 patients developed recurrence. Hematogenous recurrence was the most frequent pattern (n = 115), followed by peritoneal (n = 104) and lymph node recurrence (n = 70). Differentiated type (p = 0.0028), pT4 (p = 0.0466), and pN3 (p < 0.0001) were associated with hematogenous recurrence; however, D2+ lymphadenectomy reduced it (p = 0.0161). Patients with large (≥5 cm) tumors (p = 0.0312), pT4 (p < 0.0001), pN3 (p = 0.0013), and undifferentiated histologic type (p = 0.0001) had significantly higher rates of peritoneal recurrence. Extended lymph node metastasis (pN3) was the only risk factor (p < 0.0001) for lymph node recurrence., Conclusions: Clinicopathological features differed according to the recurrence patterns. Vigilant follow-up with an understanding of recurrence patterns might be beneficial for some high-risk patients., Competing Interests: Declaration of competing interest Masanori Terashima received personal fees from Taiho Pharmaceutical, Chugai Pharmaceutical, Ono Pharmaceutical, BMS, Yakult Honsha, Takeda Pharmaceutical, Eli Lilly Japan, Pfizer Japan, Daiichi-Sankyo, Johnson and Johnson, Medtronic Japan, Intuitive Japan, and Olympus outside the submitted work. Junki Mizusawa received personal fees from Taiho Pharmaceutical and Chugai Pharmaceutical outside the submitted work, and his spouse is employed by Pfizer. Yukinori Kurokawa received lecture fees from Taiho Pharmaceutical outside the submitted work. Takeshi Sano received lecture fees from Taiho Pharmaceutical, Chugai Pharmaceutical, Ono Pharmaceutical, Lilly, and Daiichi-Sankyo outside the submitted work. The other authors declare no conflict of interest., (Copyright © 2022 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: We herein investigated the association between early tumor shrinkage (ETS) and depth of response (DpR) and clinical outcomes in patients with metastatic esophageal cancer treated with 2-weekly docetaxel combined with cisplatin plus fluorouracil (bDCF) using data from the JCOG0807, a phase I/II trial of bDCF as first-line chemotherapy for metastatic esophageal cancer., Methods: ETS was defined as a percent decrease in the sum of the target lesions' longest diameter after 8 weeks, whereas DpR was defined as a percentage of the maximal tumor shrinkage during the treatment course. Multivariable analyses were conducted to identify significant prognostic variables in progression-free survival (PFS) and overall survival (OS): one for ETS and covariates, and another for DpR and covariates., Results: Among 53 patients, 35 patients with ETS ≥ 20% (66.0%) had longer PFS (7.5 vs. 3.4 months, hazard ratio [HR]: 0.26, 95% confidence interval [95% CI] 0.14-0.49), OS (13.8 vs. 6.1 months, HR 0.20, 95% CI 0.11-0.39), and PPS (6.4 vs. 2.8 months, HR 0.38, 95% CI 0.20-0.72) than those with ETS < 20%. In addition, 37 patients with DpR ≥ 30% (69.8%) had longer PFS (7.5 vs. 2.9 months, HR 0.17, 95% CI 0.08-0.34), OS (13.8 vs. 6.0 months, HR 0.14, 95% CI 0.07-0.27), and PPS (6.8 vs. 2.8 months, HR 0.30, 95% CI 0.15-0.58) than those with DpR < 30%. Multivariable analyses revealed that each ETS and DpR was an independent factor of longer PFS and OS., Conclusions: ETS and DpR might be associated with clinical outcomes in patients with metastatic esophageal cancer treated with bDCF., (© 2022. The Author(s) under exclusive licence to The Japan Esophageal Society.)

Introduction: Splenectomy for proximal gastric cancer was found to offer no survival benefit in a randomized trial clarifying the role of splenectomy (JCOG0110 study). Although many studies have explored risk factors for morbidities following total gastrectomy, none have assessed the risk factors for postoperative complications in spleen-preserving total gastrectomy., Methods: Using data from 505 patients enrolled in a previous randomized trial, risk factors for postoperative complications were identified by multivariable logistic regression analysis. Then, the risk factors were assessed separately between splenectomy and spleen-preserving total gastrectomy., Results: Postoperative complications were identified in 119 patients (23.6%) and were more common following splenectomy than following spleen-preserving surgery (30.7% and 16.1%, respectively, p &lt; 0.01). Multivariable analysis revealed that age ≥65 years (p = 0.032), body mass index ≥25 (p = 0.003), and blood loss ≥350 (p = 0.019) were independent risk factors for postoperative complications in the entire cohort. Among them, only body mass index was a significant independent risk factor for complications in both spleen preservation (p = 0.047) and splenectomy groups (p = 0.017)., Conclusion: Risk factors for postoperative complications were essentially the same between splenectomy and spleen preservation. Being overweight increased the risk of postoperative complications., (© 2023 S. Karger AG, Basel.)

Background: Bursectomy, the total resection of the bursa omentalis, is a standard procedure in gastrectomy for resectable gastric cancer. A phase III trial (JCOG1001) comparing bursectomy and omentectomy alone was terminated early at the interim analysis. The final results of the updated analysis after a minimum follow-up of 5 years are reported here., Methods: Patients with histologically proven adenocarcinoma of the stomach (cT3-T4a) were randomized (1 : 1) during surgery to bursectomy or omentectomy-alone groups and then underwent D2 gastrectomy. The primary endpoint was overall survival, analysed on an intention-to-treat basis., Results: A total of 1204 patients (602 bursectomy and 602 omentectomy alone) were enrolled between June 2010 and March 2015. The bursectomy group had a significantly higher incidence of Clavien-Dindo grade III-IV intra-abdominal abscess than the omentectomy-alone group (5.5 versus 2.5 per cent respectively; P = 0.008). The updated 5-year overall survival rates were 74.9 (95 per cent c.i. 71.2 to 78.2) per cent in the bursectomy group and 76.5 (72.8 to 79.7) per cent in the omentectomy-alone group; the adjusted HR for death in the bursectomy group was 1.03 (95 per cent c.i. 0.83 to 1.27) (1-sided P = 0.598). Bursectomy did not decrease peritoneal recurrence (12.1 versus 12.3 per cent respectively; P = 1.000). In a multivariable analysis, old age (above 65 years), tumour located in the lower third or posterior wall of the stomach, macroscopic type 3/5, total gastrectomy, and cT4a were independent predictors of poor overall survival, but omentectomy alone was not., Conclusion: In D2 gastrectomy, bursectomy is not recommended as a standard procedure for cT3-T4a gastric cancer. Registration number: UMIN000003688 (https://www.umin.ac.jp/ctr/)., (© The Author(s) 2022. Published by Oxford University Press on behalf of BJS Society Ltd. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The blood concentration of S-1 and adverse events are affected by renal function. Herein, an S-1 dosage formula was developed based on renal function, indicating the dose for a target blood concentration. This study aimed to explore the usefulness of the formula in adjuvant chemotherapy for gastric cancer., Methods: In this ad hoc analysis of the JCOG1001 trial, which evaluated the role of bursectomy for resectable gastric cancer, the recommended dose of S-1 was calculated using the following formula: 1447.8 × (14.5 + 0.301 × CLcr + 8.23 × SEX [male = 1, female = 0]) × body surface area (BSA) (mg/day). Patients were divided into three groups by comparing the initial S-1 dose determined using BSA with the dose recommended by the formula: underdose (UD), equal dose (ED), and overdose (OD)., Results: Among 686 eligible patients, 58, 304, and 324 patients were classified into the UD, ED, and OD groups. The patients' characteristics in the UD/ED/OD groups were median age (53.5/64.0/67.5 years), male sex (98.3%/75.3%/58.0%), and median BMI (24.8/22.8/22.3), respectively. The planned 1-year adjuvant S-1 therapy was completed in 74.1%/73.7%/68.5%, dose reduction was required in 8.6%/21.1%/30.6%, and treatment schedule was altered in 8.6%/17.1/19.8% in the UD/ED/OD groups, resulting in the 5-year overall survival rates of 77.3%/74.3%/77.0%, respectively. The incidences of grade > 3 anemia, thrombocytopenia, diarrhea, stomatitis, and anorexia were significantly higher in the OD group than in the ED and UD groups., Conclusions: Dose optimization using an S-1 dosage formula can potentially reduce grade ≥ 3 adverse events for overdosed patients., (© 2022. The Author(s).)

Background: Indications for adjuvant chemotherapy for advanced gastric cancer are determined based on the pathological diagnosis. However, macroscopic diagnoses have been reported as predictors of peritoneal recurrence and survival. This study investigated the predictability of peritoneal recurrence and survival based on macroscopically (sT) and pathologically (pT) diagnosed serosal invasion to identify more sensitive predictors of peritoneal recurrence., Methods: This study included 396 patients who underwent R0 resection without adjuvant chemotherapy with S-1 in the JCOG0110 study. Tumor depth limited to the subserosa (SS) was defined as serosal invasion negative (T-), while tumors with serosal invasion (SE, SI) were defined as serosal invasion positive (T+). The predictability of peritoneal recurrence based on sT and pT was evaluated using the Fine and Gray model. Cox regression analyses were performed for overall survival (OS) and relapse-free survival (RFS) with sT or pT as covariates., Findings: A total of 150 patients (37.9%) were sT+ and 82 (26.3%) were pT+. Sixty-two patients (15.7%) were sT+/pT+, 88 (22.2%) were sT+/pT-, 20 (5.1%) were sT-/pT+, and 226 (57.1%) were sT-/pT-. Both sT and pT were found to be independent predictors of peritoneal recurrence, OS, and RFS. The 5-year RFS rates of sT+/pT+, sT+/pT-, sT-/pT+, and sT-/pT-patients were 45.2%, 63.6%, 55.0%, and 81.8%, respectively., Conclusion: Intraoperatively diagnosed macroscopic serosal invasion showed a similar predictive value for peritoneal recurrence as pathologically diagnosed serosal invasion. The establishment of a novel staging system incorporating macroscopic serosal invasion is recommended., Competing Interests: Declaration of competing interest MT reports lecture fees from Taiho Pharmaceutical, Chugai Pharmaceutical, Ono Pharmaceutical, Bristol-Myers Squibb, Yakult Honsha, Takeda Pharmaceutical, Eli Lilly Japan KK, Pfizer Pharmaceutical, Daiichi Sankyo, Johnson and Johnson, Medtronic Japan, Intuitive Japan, Olympus outside the submitted work. JM reports the funding from National Cancer Center, Japan and the Ministry of Labour and Welfare, Japan for the present study, and personal fees from Chugai Pharmaceutical, outside the submitted work. TS reports personal fees from Taiho Pharma, Chugai Pharma, Ono Pharma, Eli Lilly, outside the submitted work. TY reports grants from Eli Lilly japan, personal fees from MSD, BMS, Ono, Taiho, Lilly, Chugai, Pfizer, Nihon Kayaku, Terumo, Otsuka, Myarisan, EA pharma, Astra-Zeneca, Covidien, Johnson and Johnson outside the submitted work. NB received a research grant from Ono and Takeda and honorarium from Taiho, Ono, Bristol-Myers Squibb outside the submitted work. MS reports lecture fees from Taiho Pharmaceutical and Eli Lilly, travel support from Eli Lilly outside the submitted work, and has served as Chairman of the board of directors of the Japan Gastric Cancer Association and member of the Guideline committee of the Japan Gastric cancer Association during the study period. All the other authors declare no competing interests. Red lines represent serosal invasion positive and blue lines represent serosal invasion negative. The C-index was calculated using the Fine and Gray model., (Copyright © 2022 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: To improve the diagnostic accuracy of preoperative T staging in gastric cancer, the authors evaluated tumor-related factors that might affect the diagnosis. Materials & methods: The authors analyzed the data of cT2-4b gastric cancer patients enrolled in the prospective, multicenter JCOG1302A study. They used contrast-enhanced computed tomography to analyze the association between tumor-related factors and the diagnostic accuracy of T3-4b staging for gastric cancer. Results: Among 876 cT3-4b tumors, the diagnostic accuracy was relatively low in the lower third of the stomach compared with those in the upper or middle. A multivariable analysis revealed that accuracy was higher in the lesser curvature or entire circumference region than in other areas (p < 0.001), in macroscopic types 3/5 than in types 0/1/2 (p = 0.003) and in the undifferentiated histological type than in the differentiated type (p = 0.011). Conclusion: The authors found tumor-related factors affecting preoperative T staging by enhanced computed tomography.

Background and Aim: Endoscopic submucosal dissection (ESD) is recommended for the treatment of early gastric cancers with an undifferentiated-type component, clinically diagnosed as intramucosal lesions ≤ 2 cm, without ulceration. In the JCOG1009/1010 trial, ESD could be performed with stomach preservation in 70% of such patients whose pathological findings met the curative resection criteria. However, additional gastrectomy was required for the remaining 30%. We identified the pretreatment risk factors for noncurative resection., Methods: Post-hoc analysis indicated that 336 patients were identified in the JCOG1009/1010 trial; among them, 243 and 93 patients were categorized into the curative or noncurative resection groups, respectively, based on the pathological findings of the resected specimens. We explored the pretreatment risk factors for noncurative resection and investigated their associated pathological findings., Results: Multivariable analysis revealed that a pretreatment tumor size > 1 cm was an independent risk factor for noncurative resection (odds ratio, 3.538; 95% confidence interval, 2.020-6.198, P < 0.0001). Patients with a pretreatment tumor size > 1 cm (n = 172) had a histological tumor size > 2 cm (22.1% vs 4.3%, odds ratio, 6.313; 95% confidence interval, 2.73-14.599, P < 0.0001) and submucosal invasion (17.4% vs 9.1%, odds ratio, 2.000; 95% confidence interval, 1.032-3.877, P = 0.040) more frequently as noncurative resection findings compared with those with a tumor size < 1 cm (n = 164)., Conclusions: Because pretreatment tumor size > 1 cm is an independent risk factor for noncurative resection, endoscopists should be aware that noncurative resection is not uncommon in ESD and fully explain the potential necessity for additional gastrectomy to patients before the procedure., (© 2022 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background and Aims: Endoscopic resection (ER) for early gastric cancer (EGC) can preserve the stomach; however, the remaining stomach can develop second gastric cancer. Few reports have prospectively investigated the incidence and treatment outcomes of second gastric cancer., Methods: This post-hoc analysis used the dataset of the single-arm confirmatory trial, JCOG0607. The key inclusion criteria for JCOG0607 were solitary differentiated-type EGC and no previous gastrectomy or endoscopic treatment for EGC. Three hundred seventeen patients who underwent curative ER were included in this study. Surveillance endoscopy was performed 1 to 3 months after the initial ER and subsequently annually for at least 5 years. A lesion detected ≤1 year and >1 year after the initial ER was defined as overlooked gastric cancer (OGC) and metachronous gastric cancer (MGC), respectively., Results: During a median follow-up period of 6.0 years (interquartile range, 5.1-7.0), 30 OGCs and 61 MGCs were detected in 24 and 48 patients, respectively. The cumulative incidence of OGC at 1 year and MGC at 5 years was 7.6% and 12.7%, respectively. ER and gastrectomy were performed in 85 lesions and 6 lesions, respectively. Pathologic evaluation showed 78 mucosal cancers, 12 submucosal cancers, and 1 advanced cancer. Eventually, 28 OGCs and 52 MGCs fulfilled the pathologic criteria for curative ER., Conclusions: Our study was the first to reveal the actual incidence of second gastric cancer after curative ER for differentiated-type gastric cancer. Most lesions could be treated with ER. Continuous endoscopic surveillance after curative ER is important to detect second gastric cancer., (Copyright © 2022 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: Recent retrospective studies have shown that increased intraoperative blood loss (IBL) during curative gastrectomy for patients with advanced gastric cancer is a negative prognostic indicator for recurrence. However, there are no reliable reports assessing this with a large-scale prospective cohort. This study aimed to evaluate the impact of IBL on long-term outcomes using data from the JCOG1001 phase III trial, which was designed to determine if bursectomy led to improved survival vs. nonbursectomy in patients with cT3/4a gastric cancer., Methods: This study included 1203 of the 1204 patients enrolled in the JCOG1001. From the tertiles of IBL (196 ml, 400 ml), we divided the patients into three groups: IBL < 200 ml representing small blood loss (SBL, n = 404), 200 ml ≤ IBL < 400 ml representing medium blood loss (MBL, n = 393), and IBL ≥ 400 ml representing large blood loss (LBL, n = 406). The impact of IBL on relapse-free survival (RFS) was evaluated with univariable comparisons and multivariable Cox regression analyses., Results: Three-year RFS after SBL, MBL, and LBL was 81.7%, 74.8%, and 70.6%, respectively. Multivariable analysis identified IBL, Eastern Cooperative Oncology Group performance status, pT, pN, and postoperative adjuvant chemotherapy as independent predictors of RFS. Compared with SBL as a reference, the hazard ratios of MBL and LBL were 1.461 (P = 0.012) and 1.520 (P = 0.009), respectively., Conclusions: Based on the analysis of data from a large-scale prospective study, an IBL of ≥ 200 ml after curative surgery for patients with cT3/4a gastric cancer was an independent predictor of reduced RFS., (© 2021. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background and Aims: A drawback of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) is the development of metachronous gastric cancer (MGC). While MGC after ESD for differentiated-type (D-) EGC was well understood, little is known about MGC occurring after ESD for undifferentiated-type (UD-) EGC, because ESD had not been indicated. We evaluated the incidence and treatment outcomes of MGC after ESD of UD-EGC., Methods: This study is a post hoc analysis of JCOG1009/1010, a multicenter trial to evaluate the efficacy and safety of ESD for UD-EGC. The patients who underwent curative ESD of index solitary UD-EGC were analyzed. Surveillance endoscopy was performed biannually for the first 3 years and thereafter annually. We assessed the time to MGC occurrence after ESD, lesion characteristics, and treatment outcomes of MGC. Time to MGC occurrence was estimated by cumulative incidence function, with death and total gastrectomy as competing risks., Results: A total of 198 patients were included in this study. During a median follow-up period of 5.8 years, 4 patients (2%) developed MGC. Median time to MGC occurrence was 4.5 years (range: 3.1-5.4). Five-year cumulative incidence of MGC was 1.0% (95% CI: 0.2-3.3%). Two MGCs were histologically D-EGC, and the remaining two were UD-EGC. The median tumor size of MGCs was 1.0 cm (range: 0.7-1.7), and the depth of invasion (M/SM1/SM2) was 2/1/1, respectively. Three patients achieved curative resection with repeated ESD., Conclusions: MGC does not occur commonly after curative ESD of UD-EGC, and repeated ESD could contribute to stomach preservation., (© 2021. The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: Specific treatment strategies are sorely needed for scirrhous-type gastric cancer still, which has poor prognosis. Based on the promising results of our previous phase II study (JCOG0210), we initiated a phase III study to confirm the efficacy of neoadjuvant chemotherapy (NAC) in type 4 or large type 3 gastric cancer., Methods: Patients aged 20-75 years without a macroscopic unresectable factor as confirmed via staging laparoscopy were randomly assigned to surgery followed by adjuvant chemotherapy with S-1 (Arm A) or NAC (S-1plus cisplatin) followed by D2 gastrectomy plus adjuvant chemotherapy with S-1 (Arm B). The primary endpoint was overall survival (OS)., Results: Between October 2005 and July 2013, 316 patients were enrolled, allocating 158 patients to each arm. In Arm B, in which NAC was completed in 88% of patients. Significant downstaging based on tumor depth, lymph node metastasis, and peritoneal cytology was observed using NAC. Excluding the initial 16 patients randomized before the first revision of the protocol, 149 and 151 patients in arms A and B, respectively, were included in the primary analysis. The 3-year OS rates were 62.4% [95% confidence interval (CI)  54.1-69.6] in Arm A and 60.9% (95% CI  52.7-68.2) in Arm B. The hazard ratio of Arm B against Arm A was 0.916 (95% CI  0.679-1.236)., Conclusions: For type 4 or large type 3 gastric cancer, NAC with S-1 plus cisplatin failed to demonstrate a survival benefit. D2 surgery followed by adjuvant chemotherapy remains the standard treatment.

Gastrectomy with omentectomy and D2 lymph node dissection is the current standard procedure for locally advanced gastric cancer. However, some retrospective studies have reported that omentectomy increased post-operative abdominal complications but provided no survival advantage over omentum preservation. Therefore, we plan a randomized controlled phase III trial to confirm the non-inferiority of omentum preservation compared with omentectomy in patients with cT3 (SS) or cT4a (SE) gastric cancer. A total of 1050 patients will be enrolled from 62 institutions over a period of 6.5 years. The primary end point is relapse-free survival, and the secondary end points are overall survival, blood loss, operation time and adverse events. This trial has been registered at the UMIN Clinical Trials Registry as UMIN000036253., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Oral fluoropyrimidine plus cisplatin is often not tolerated by patients with severe peritoneal metastases of gastric cancer. Combination of 5-fluorouracil (5-FU), l-leucovorin (l-LV), and paclitaxel (FLTAX) has promising activity for such patients. We conducted a phase II/III study comparing FLTAX with 5-FU/l-LV., Methods: Eligibility criteria included: unresectable or recurrent gastric adenocarcinoma; 20-75 years; performance status (PS) 0-2; peritoneal metastases + ; massive ascites and/or inadequate oral intake; no prior chemotherapy. Patients were randomly assigned to receive 5-FU/l-LV or FLTAX. The primary endpoint of phase III was overall survival: UMIN000010949., Results: We enrolled 101 patients. Early deaths occurred in patients with PS 2 having massive ascites and inadequate oral intake simultaneously; the protocol was amended to exclude such patients. Median survival times were 6.1 and 7.3 months for the 5-FU/l-LV and the FLTAX arms, respectively (HR 0.792; 80% CI 0.596-1.053; one-sided p = 0.1445). FLTAX arm had longer progression-free survival (PFS) [1.9 vs 5.4 months (HR 0.64; 95% CI, 0.43-0.96; p = 0.029)]. Grade 3/4 adverse events such as leucopenia and anorexia were more frequently observed in the 5-FU/l-LV arm. In the 5-FU/l-LV arm, two deaths were treatment-related. In the 5-FU/l-LV and FLTAX arms, 12 and 3 deaths occurred within 30 days after the last protocol treatment, respectively., Conclusions: Chemotherapy was indicated for patients with severe peritoneal metastases excluding patients with PS 2 having massive ascites and inadequate oral intake simultaneously. FLTAX did not confer a significant survival benefit but may be preferred because of longer PFS and acceptable toxicity.

Background: Neoadjuvant chemotherapy (NAC) is increasingly used for resectable locally advanced gastric cancer (LAGC). JCOG1302A investigated the diagnostic criteria of LAGC patients with cT3-4/N1-3 to minimize contamination of pathological stage I as a candidate for NAC. In JCOG1302A, 77.2% of cT3-4 tumors diagnosed via a combination of endoscopy and computed tomography (CT) were pT3-4. However, the role of endoscopic ultrasonography (EUS) and additional diagnostic procedures/modalities remains unclear. Here, we investigated whether EUS, thin-slice CT, and foaming agent (FA) in CT contribute to accurate diagnosis of AGC invasion depth., Methods: Using JCOG1302A study data, we compared positive predictive value (PPV), negative predictive value (NPV), and kappa index (KI) between conventional and additional diagnostic procedures to identify pT3-4: conventional endoscopy (CE) with versus without EUS, 1-mm versus 5-mm CT slice, and CT with versus without FA., Results: We analyzed 1232 patients' data. PPV, NPV, and KI were 79.2%/73.7%, 59.2%/58.8%, and 0.38/0.39 (CE alone/CE with EUS), 77.8%/75.5%, 62.9%/71.2%, and 0.38/0.39 (5-mm CT/1-mm CT), and 78.6%/75.1%, 60.9%/69.7%, and 0.38/0.40 (CT without FA/CT with FA), respectively. Overall, there were no remarkable differences in any comparison. More specifically, PPV and KI were slightly higher with CE alone rather than CE with EUS. Although NPV was higher for 1-mm CT and CT with FA, PPV was rather higher for 5-mm CT and CT without FA., Conclusion: Additional diagnostic procedures/modalities, like EUS, 1-mm slice CT, or FA in CT may not improve the diagnostic accuracy of invasion depth in resectable LAGC., Competing Interests: Declaration of competing interest No., (Copyright © 2020 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: Preoperative chemotherapy with cisplatin plus S-1 (CS) followed by gastrectomy with D2 plus para-aortic lymph node (PAN) dissection is regarded as a standard treatment in Japan for advanced gastric cancer with bulky lymph node (BN) and/or PAN metastasis. In the JCOG1002, we added docetaxel to CS (DCS) to further improve long-term outcomes. However, the primary endpoint, clinical response rate (RR), did not reach the expected level (Ito et al. in Gastric Cancer 20:322-31, 2017). Herein, we report our long-term survival results., Methods: Patients with BN and/or PAN metastasis received 2 or 3 cycles of DCS therapy (docetaxel at 40 mg/m 2 and cisplatin at 60 mg/m 2 on day 1 and S-1 at 80 mg/m 2 per day for 2 weeks, followed by a 2-week rest) followed by gastrectomy with D2 plus PAN dissection and postoperative S-1 for 1 year., Results: Between July 2011 and May 2013, 53 patients were enrolled. Clinically, 17.0% had both PAN and BN metastasis, and the rest had either PAN (26.4%) or BN (56.6%) metastasis. Among all eligible patients, the 5-year overall survival was 54.9% (95% confidence interval 40.3-67.3%) at the last follow-up in May 2018. Among 44 eligible patients with R0 resection, the 5-year relapse-free survival was 47.7% (95% confidence interval 32.5-61.5%)., Conclusions: Adding docetaxel to CS in preoperative chemotherapy for extensive nodal metastasis improved neither short-term outcomes nor long-term survival. Preoperative chemotherapy with CS followed by D2 + PAN dissection and postoperative S-1 remains the standard of care for patients with extensive nodal metastasis.

Background : Although surgical resection is necessary to cure the locally advanced gastric cancer, it is sometimes difficult for extensive nodal metastasis such as para-aortic nodal disease or bulky nodal metastasis around the major gastric branched arteries. We had conducted several Phase II studies and clarified preoperative chemotherapy with doublet regimen followed by surgery markedly improved the survival for this disease. Recently, preoperative chemotherapy with docetaxel, oxaliplatin and S-1 (DOS) showed promising efficacy and acceptable feasibility for resectable advanced gastric cancer. Aim: To describe the design and rationale for the multi-institutional, single-arm, Phase II trial of systemic chemotherapy with DOS followed by surgery in advanced gastric cancer with extensive lymph node metastasis (JCOG1704). If efficacy and safety of DOS can be shown, we will conduct a Phase III trial comparing preoperative DOS and current standard cisplatin and S-1. Trial registration: jRCTs031180028.

Background: Laparoscopy-assisted distal gastrectomy (LADG) is increasingly being used as an alternative to open distal gastrectomy (ODG) for gastric cancer treatment. Retrospective studies have shown equivalent survival with the two procedures, but these studies are limited by selection bias because LADG is more technically difficult than ODG. We aimed to evaluate whether LADG was non-inferior to ODG in terms of long-term survival outcomes., Methods: We did an open-label, multicentre, non-inferiority, phase 3 randomised controlled trial at 33 institutions in Japan. Patients aged 20-80 years with histologically confirmed gastric adenocarcinoma (T1N0, T1N1, or T2[MP]N0), clinical stage I, in the middle or lower third of the stomach, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, with a body-mass index of less than 30 kg/m 2 , were randomly assigned (1:1) to receive ODG or LADG. Randomisation was done by telephone, fax, or with a web-based system in the Japan Clinical Oncology Group Data Center; a minimisation method with a random component was used to adjust for institution and clinical stage (IA or IB). Only study-accredited surgeons performed ODG and LADG. The primary endpoint was relapse-free survival and was analysed according to the intention-to-treat principle. The non-inferiority margin (LADG vs ODG) was set at a hazard ratio (HR) of 1·54. The trial was registered with the UMIN Clinical Trials Registry, UMIN000003319., Findings: Between March 15, 2010, and Nov 29, 2013, 921 patients were enrolled and randomly assigned to receive ODG (n=459) or LADG (n=462). 912 (99%) participants had the assigned surgery. 5-year relapse-free survival was 94·0% (95% CI 91·4-95·9) in the ODG group and 95·1% (92·7-96·8) in the LADG group. LADG was non-inferior to ODG for relapse-free survival (HR 0·84 [90% CI 0·56-1·27]), p=0·0075). The most common grade 3 or 4 adverse event was bowel obstruction, occurring in 11 (2%) of 455 patients in the ODG group and five (1%) of 457 patients in the LADG group. There were no treatment-related deaths., Interpretation: This trial supports the non-inferiority of LADG compared with ODG for clinical stage I gastric cancer relapse-free survival, suggesting that LADG should be considered a standard treatment option when performed by experienced surgeons., Funding: Japan National Cancer Center, Ministry of Health, Labour and Welfare of Japan, Japan Agency for Medical Research and Development., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Gastric cancer with extensive lymph node metastasis is commonly regarded as unresectable, while preoperative chemotherapy followed by gastrectomy has been tested since 2000 in JCOG (JCOG0001 and JCOG0405). The survivals were quite different between the trials despite the similar eligibility criteria. The aim of this study was to investigate if survival is still better in JCOG0405 after adjusting baseline factors and if there is any subset of patients who benefit more from either treatment., Methods: Eligibility criteria for both trials included histologically proven gastric adenocarcinoma; bulky nodal involvement around the celiac artery and its major branches (bulky N) and/or para-aortic lymph node (PAN); cM0 (except PAN); negative lavage cytology; not linitis plastica type; PS of 0 or 1. Patients received two or three cycles of preoperative chemotherapy of irinotecan plus cisplatin in JCOG0001, or S-1 plus cisplatin in JCOG0405, followed by D3 gastrectomy. Multivariable analysis for overall survival adjusting baseline and treatment factors was performed with the Cox regression model., Results: After adjusting baseline factors, S-1 plus cisplatin was superior to irinotecan plus cisplatin for overall survival (HR = 0.39: 95% CI 0.22-0.67). The 5-year overall survival was poor for patients with bulky N+/PAN+ (19.2%) compared with bulky N+/PAN- (50.7%) or bulky N-/PAN+ (43.5%)., Conclusions: S-1 plus cisplatin was shown to be a favorable preoperative treatment for gastric cancer with extensive lymph node metastasis by multivariable analysis, while poor prognosis in patients having both bulky N+ and PAN+ may necessitate further treatment improvement.

Background: The prognosis of patients with linitis plastica (type 4) and large (≥ 8 cm) ulcero-invasive-type (type 3) gastric cancer is extremely poor, even after extended surgery and adjuvant chemotherapy. Given the promising results of our previous phase II study evaluating neoadjuvant chemotherapy (NAC) with S-1 plus cisplatin (JCOG0210), we performed a phase III study to confirm the efficacy of NAC in these patients, with the safety and surgical results are presented here., Methods: Eligible patients were randomized to gastrectomy plus adjuvant chemotherapy with S-1 (Arm A) or NAC followed by gastrectomy + adjuvant chemotherapy (Arm B). The primary endpoint was the overall survival (OS). This trial is registered at the UMIN Clinical Trials Registry as C000000279., Results: From February 2007 to July 2013, 300 patients were randomized (Arm A 149, Arm B 151). NAC was completed in 133 patients (88%). Major grade 3/4 adverse events during NAC were neutropenia (29.3%), nausea (5.4%), diarrhea (4.8%), and fatigue (2.7%). Gastrectomy was performed in 147 patients (99%) in Arm A and 139 patients (92%) in Arm B. The operation time was significantly shorter in Arm B than in Arm A (median 255 vs. 240 min, respectively; p = 0.024). There were no significant differences in Grade 2-4 morbidity and mortality (25.2% and 1.3% in Arm A and 15.8% and 0.7% in Arm B, respectively)., Conclusions: NAC for type 4 and large type 3 gastric cancer followed by D2 gastrectomy can be safely performed without increasing the morbidity or mortality.

Backgrounds: Laparoscopy-assisted distal gastrectomy (LADG) for gastric cancer is safe and feasible. In contrast, no prospective study evaluating the safety and efficacy of laparoscopy-assisted total gastrectomy (LATG) or laparoscopy-assisted proximal gastrectomy (LAPG) has been completed. We conducted a single-arm confirmatory trial to evaluate the safety of LATG/LAPG for clinical stage I (T1N0/T1N1/T2N0) proximal gastric cancer., Methods: The extent of lymphadenectomy was selected based on the Japanese Gastric Cancer Treatment Guidelines. The mini-laparotomy incision was required to be ≤ 6 cm. The primary endpoint was the proportion of grade 2-4 (CTCAE ver. 4.0) esophagojejunal anastomotic leakage. The planned sample size was 245 considering a threshold of 8% and one-sided alpha of 2.5%., Results: Between April 2015 and February 2017, 244 eligible patients were enrolled. LATG/LAPG was performed in 195/49. The proportion of conversions was 1.7%. Clinical T1N0/T1N1/T2N0 was 212/9/23. The extents of lymphadenectomy were as follows: D1+: 229; D2: 15. The median operation time was 309 min (IQR 265-353). The median blood loss was 30 ml (IQR 10-86). Grade 2-4 esophagojejunal anastomotic leakage was 2.5% (6/244; 95% CI 0.9-5.3). The overall proportion of in-hospital grade 3-4 adverse events was 29% (71/244). The proportions of intraabdominal abscess and pancreatic fistula were 3.7% and 2.0%, respectively. There were no treatment-related deaths., Conclusions: This trial confirmed the safety of LATG/LAPG. After the non-inferiority of LADG is confirmed in our phase III trial (JCOG0912), LATG/LAPG is expected to be established as one of the standard treatments for clinical stage I gastric cancer.

Background: We investigated the superiority of docetaxel plus cisplatin and S-1 compared with cisplatin and S-1 in chemotherapy-naive patients with advanced gastric cancer., Methods: In this open-label, phase 3, randomised controlled trial, patients were recruited from 56 hospitals in Japan. We enrolled individuals aged 20-75 years who had unresectable or recurrent gastric cancer, had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, had received no previous chemotherapy (except adjuvant chemotherapy completed 24 weeks before reccurence), radiotherapy, or hormonal therapy, could take drugs orally, and had adequate organ function. Patients were randomly assigned (1:1) to receive docetaxel plus cisplatin and S-1 (docetaxel 40 mg/m 2 and cisplatin 60 mg/m 2 on day 1 intravenously, and S-1 40-60 mg twice a day orally for 2 weeks, every 4 weeks) or cisplatin and S-1 (cisplatin 60 mg/m 2 intravenously on day 8, and S-1 40-60 mg orally twice a day for 3 weeks, every 5 weeks). Randomisation was done centrally with the minimisation method, with a random component balancing for institution, ECOG performance status (0 vs 1), disease status at enrolment (unresectable vs recurrent), measurable lesion (yes vs no), number of metastatic sites (0-1 vs ≥2), and histological type (differentiated vs undifferentiated). Neither investigators or patients were masked to the study treatment. The primary endpoint was overall survival in the intention-to-treat population. The study is registered with UMIN-CTR, number UMIN000007652., Findings: Between April 3, 2012, and March 18, 2016, 741 patients were randomly assigned to receive docetaxel plus cisplatin and S-1 (n=370) or cisplatin and S-1 (n=371). Median overall survival was 14·2 months (95% CI 12·9-15·9) in the docetaxel plus cisplatin and S-1 group and 15·3 months (14·2-16·2) in the cisplatin and S-1 group (hazard ratio [HR] 0·99 [95% CI 0·85-1·16]; one-sided stratified log-rank p=0·47). The most common grade 3 or worse adverse events were neutropenia (209 [59%] of 357 patients in the docetaxel plus cisplatin and S-1 group vs 117 [32%] of 365 patients in the cisplatin and S-1 group), leukopenia (120 [34%] vs 60 [16%]), and anorexia (94 [26%] vs 81 [22%]). The deaths of one patient in the cisplatin and S-1 group and in three patients in the docetaxel plus cisplatin and S-1 group were deemed treatment-related., Interpretation: The addition of docetaxel to cisplatin and S-1 did not improve overall survival in chemotherapy-naive Japanese patients with advanced gastric cancer. Therefore, cisplatin and S-1 remains the standard first-line chemotherapy., Funding: Ministry of Health, Labour and Welfare and Japan Agency for Medical Research and Development., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Postoperative adjuvant chemotherapy with S-1 for 1 year (corresponding to eight courses) is standard care for stage II gastric cancer. Whether the duration of S-1 could be shortened to 6 months (corresponding to four courses) without worsening survival is unclear. The aim of this study was to investigate the non-inferiority of four courses of S-1 compared with eight courses of S-1 for patients with stage II gastric cancer., Methods: We did a phase 3, open-label, randomised controlled, non-inferiority trial at 59 hospitals in Japan. Patients aged 20-80 years with stage II adenocarcinoma of the stomach were randomly assigned (1:1) to eight courses or four courses of S-1. Randomisation was done by the Japan Clinical Oncology Group Data Center website, using a minimisation method with a random component using institution, stage (IIA vs IIB), age (<70 years vs ≥70 years), and mode of operation (open gastrectomy with bursectomy vs open gastrectomy without bursectomy vs laparoscopic gastrectomy) as adjustment factors. One course was 80 mg/day per m 2 of S-1 administered for 4 weeks followed by a rest for 2 weeks. The primary endpoint was relapse-free survival, analysed by intention to treat, with a non-inferiority margin for the hazard ratio (HR) set at 1·37. This study is registered at UMIN-Clinical Trial Registry, number UMIN000007306., Findings: Between Feb 16, 2012, and March 19, 2017, 590 patients were enrolled (295 per group). 528 (89%) patients were analysed at the first planned interim analysis in March, 2017, at which time the point estimate of HR for the four-course group compared with the eight-course group was 2·52 (95% CI 1·11-5·77), which exceeded 1·37 and met the prespecified criteria for early termination. Predictive probability for showing non-inferiority at the final analysis was calculated to be 2·9%. The study was stopped for futility. Updated 3-year relapse-free survival analysed in May, 2017, was 93·1% (95% CI 87·8-96·1) for the eight-course group and 89·8% (84·2-93·5) for the four-course group (HR 1·84, 95% CI 0·93-3·63). The most common grade 3-4 adverse event was neutropenia, observed in 46 (16%) patients in the eight-course group and 51 (17%) patients in the four-course group., Interpretation: S-1 for 1 year should remain as standard adjuvant chemotherapy for stage II gastric cancer., Funding: Japan Agency for Medical Research and Development; the Ministry of Health, Labour and Welfare of Japan; the National Cancer Center Research and Development Fund, Japan., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Adjuvant chemotherapy with S-1 is a standard treatment for patients with stage II/III gastric cancer after D2 gastrectomy; however, this is not uniformly applicable in older patients. The Stomach Cancer Study Group of the Japan Clinical Oncology Group conducted a questionnaire survey on older patients aged ≥80 years and revealed wide heterogeneity among older patients of similar chronological age. This randomized trial aims to confirm the superiority of modified S-1 treatment (reduced initial dose of S-1 by ≥ 1 level compared with the standard dose) versus surgery alone in vulnerable older (≥80 years old) patients with pathological stage II/III gastric cancer after curative resection. A total of 370 patients will be enrolled from 62 institutions over 4.5 years. The primary endpoint of this study is overall survival. This trial has been registered in the UMIN Clinical Trials Registry with code UMIN000025742 [http://www.umin.ac.jp/ctr/index.htm].

Background: The role of bursectomy, in which the peritoneal lining covering the pancreas and the anterior plane of the transverse mesocolon are dissected, has long been controversial for preventing peritoneal metastasis. We investigated the survival benefit of bursectomy in patients with resectable gastric cancer., Methods: This phase 3, open-label, randomised controlled trial was done at 57 hospitals in Japan. Patients aged 20-80 years who had cT3(SS)-cT4a(SE) histologically proven gastric adenocarcinoma with an Eastern Cooperative Oncology Group performance status of 0 or 1 and body-mass index less than 30 kg/m 2 and who did not have distant metastasis or bulky lymph nodes were randomly assigned (1:1) during surgery to receive omentectomy alone (non-bursectomy) or bursectomy. Randomisation was done by telephone or website to the Japan Clinical Oncology Group Data Center and used a minimisation method with a random component to adjust for institution, cT status (T3 vs T4a), and type of gastrectomy (distal vs total). Both groups had total or distal gastrectomy with D2 lymphadenectomy. The primary endpoint was overall survival, analysed in the intention-to-treat population. The study is registered with UMIN-CTR, number UMIN000003688., Findings: Between June 1, 2010, and March 30, 2015, 1503 patients were enrolled based on preoperative inclusion and exclusion criteria. Intraoperative inclusion and exclusion criteria were met in 1204 patients, of which 602 were allocated to the non-bursectomy group and 602 were allocated to the bursectomy group. At the planned second interim analysis on Sept 17, 2016, the JCOG Data and Safety Monitoring Committee independently reviewed the results and recommended their early publication on the basis of futility because overall survival was lower in the bursectomy group than the non-bursectomy group, and because the predictive probability of overall survival being significantly higher in bursectomy than non-bursectomy patients at the final analysis was only 12·7%. 5-year overall survival was 76·7% (95% CI 72·0-80·6) in the non-bursectomy group and 76·9% (72·6-80·7) in the bursectomy group (hazard ratio 1·05, 95% CI 0·81-1·37, one-sided p=0·65). 64 (11%) of 601 in the non-bursectomy group and 77 (13%) of 600 patients in the bursectomy group had grade 3-4 operative morbidity. Pancreatic fistula was significantly more common in the bursectomy group than in the non-bursectomy group (29 [5%] vs 15 [2%]; p=0·032). Six deaths occurred either in hospital or within 1 month of surgery: five in the non-bursectomy group and one in the bursectomy group., Interpretation: Bursectomy did not provide a survival advantage over non-bursectomy. D2 dissection with omentectomy alone should be done as a standard surgery for resectable cT3-T4a gastric cancer., Funding: Japan Agency for Medical Research and Development, the Ministry of Health, Labour and Welfare of Japan, and the National Cancer Centre Research and Development Fund., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Neoadjuvant chemotherapy (NAC) followed by radical surgery is a promising strategy to improve survival of patients with stage III gastric cancer, but is associated with the risk of preoperative overdiagnosis by which patients with early disease may receive unnecessary intensive chemotherapy., Methods: We assessed the validity of a preoperative diagnostic criterion in a prospective multicenter study. Patients with gastric cancer with a clinical diagnosis of T2/T3/T4, M0, except for diffuse large tumors and extensive bulky nodal disease, were eligible. Prospectively recorded clinical diagnoses (cT category, cN category) were compared with postoperative pathological diagnoses (pT category, pN category, and pathological stage). The primary endpoint was the proportion of pathological stage I tumors among those diagnosed as cT3/T4, which we expected to be 5% or less., Results: Data from 1260 patients enrolled from 53 institutions were analyzed. The proportion of pathological stage I tumors in those with a diagnosis of cT3/T4 (primary endpoint) was 12.3%, which was much higher than the prespecified value. The positive predictive value and the sensitivity for pathological stage III tumors were 43.6% and 87.8% respectively. The sensitivity and specificity of contrast-enhanced CT for lymph node metastasis were 62.5% and 65.7% respectively. After exploring several diagnostic criteria, we propose, for future NAC trials in Japan, a diagnosis of "cT3/T4 with cN1/N2/N3," by which inclusion of pathological stage I tumors was reduced to 6.5%, although its sensitivity for pathological stage III tumors decreased to 64.5%., Conclusion: Clinical diagnosis of T3/T4 tumors was not an optimal criterion to select patients for intensive NAC trials because more than 10% of patients with pathological stage I disease were included. We propose the criterion "cT3/T4 and cN1/N2/N3" instead.

Background: Laparoscopic gastrectomy has become a common surgical treatment for gastric cancer in eastern Asian countries. However, a large-scale prospective study to investigate the benefit of laparoscopy-assisted distal gastrectomy (LADG) regarding long-term outcomes has never been reported. We have already reported the short-term outcomes of this study. Here we report long-term outcomes as the secondary endpoints of this study after a 5-year follow-up period., Methods: This study comprised patients with clinical stage I gastric cancer who were able to undergo a distal gastrectomy. LADG with D1 plus suprapancreatic lymph node dissection was performed by credentialed gastric surgeons who had each conducted at least 30 LADG and 30 open gastrectomy procedures. The primary endpoint was the proportion of patients who developed either anastomotic leakage or pancreatic fistula. The secondary endpoints included overall survival and relapse-free survival., Results: From November 2007 to September 2008, 176 eligible patients were enrolled, comprising 140 patients with pathological stage IA disease, 23 patients with pathological stage IB disease, 9 patients with pathological stage II disease, and 4 patients with pathological stage IIIA disease. No patients had recurrent disease, and three of the patients died within the follow-up period. The 5-year overall survival was 98.2% (95% confidence interval 94.4-99.4%) and the 5-year relapse-free survival was 98.2% (95% confidence interval 94.4-99.4%)., Conclusions: The long-term outcomes of stage I gastric cancer patients undergoing LADG seem comparable to those of patients undergoing an open procedure, although this result should be confirmed by a randomized control trial. We have already completed accrual of 921 patients for a multicenter randomized phase III trial (JCOG0912) to confirm the noninferiority of LADG compared with open gastrectomy in terms of relapse-free survival.

Background: Endoscopic resection has been limited to intestinal-type gastric cancer (cT1a) with a low risk of lymph node metastasis (T1a ≤2 cm, without ulcers). This single-arm confirmatory trial evaluated the efficacy and safety of endoscopic submucosal dissection (ESD) for >2 cm ulcer-negative and ≤3 cm ulcer-positive intestinal-type gastric cancer (cT1a)., Methods: The eligibility criteria included endoscopically diagnosed cT1a, a single primary intestinal-type gastric adenocarcinoma, an ulcer-negative lesion of any size or a ≤3 cm ulcer-positive lesion, cN0M0, and no prior treatment. If ESD resulted in noncurative resection, surgical resection was added. The primary endpoint was the 5-year overall survival (OS) (planned sample size was 470, with a one-sided alpha level of 2.5%). The threshold 5-year OS was 86.1%., Results: We enrolled 470 early gastric cancer patients [median tumor size, 25 (5-130) mm] from 29 institutions between June 2007 and October 2010. These patients had 152 ulcer-negative lesions (>2 and ≤3 cm), 111 ulcer-negative lesions (>3 cm), and 207 ulcer-positive lesions (≤3 cm). The success rate for en block resection was 99.1% (466/470). Additional gastrectomy was conducted in 131 patients (28%) who did not fulfill the curative resection criteria. The 5-year OS of all patients was 97.0% (95% confidence interval, 95.0-98.2%), which was higher than the threshold 5-year OS (86.1%). The 317 patients who satisfied the curative resection criteria had no recurrence. There were no ESD-related grade 4 adverse events., Conclusion: ESD for early gastric cancers that met the expanded criteria for intestinal-type gastric cancer (cT1a) was acceptable and should be the standard treatment instead of gastrectomy.

Background: In a phase III study for advanced gastric cancer (AGC), the Japan Clinical Oncology Group (JCOG) 9912 trial, we previously identified the following four prognostic factors-performance status ≥1, number of metastatic sites ≥2, no prior gastrectomy, and abnormal serum alkaline phosphatase levels-and proposed a prognostic index (good risk with 0 or 1 factor, moderate risk with 2 or 3 factors, and poor risk with all 4 factors). To assess the generalizability of this index, we attempted an external validation study using an independent data set., Methods: Individual patient data from the SPIRITS and G-SOX trials were applied to the JCOG prognostic index. The accuracy of the index for predicting survival was assessed by the Cox proportional hazards model., Results: The available data were obtained from 936 (94.5%) of the 990 patients in these trials. The three risk groups categorized by the JCOG prognostic index demonstrated highly significant survival differences; the hazard ratios (95% confidence interval) were 1.71 (1.46-2.01) between the good (n = 338) and moderate (n = 537) risk groups and 3.32 (2.47-4.46) between good and poor (n = 61) risk groups. The median overall survival times of the good, moderate, and poor risk groups were 17.2, 12.0, and 7.8 months, respectively., Conclusions: The JCOG prognostic index was externally validated and can be widely utilized for clinical trials. Further studies are needed to apply this index to the Western population.

Backgrounds: No confirmatory randomized controlled trials (RCTs) have evaluated the efficacy of laparoscopy-assisted distal gastrectomy (LADG) compared with open distal gastrectomy (ODG). We performed an RCT to confirm that LADG is not inferior to ODG in efficacy., Methods: We conducted a multi-institutional RCT. Eligibility criteria included histologically proven gastric adenocarcinoma in the middle or lower third of the stomach, clinical stage I tumor. Patients were preoperatively randomized to ODG or LADG. This study is now in the follow-up stage. The primary endpoint is relapse-free survival (RFS) and the primary analysis is planned in 2018. Here, we compared the surgical outcomes of the two groups. This trial was registered at the UMIN Clinical Trials Registry as UMIN000003319., Results: Between March 2010 and November 2013, 921 patients (LADG 462, ODG 459) were enrolled from 33 institutions. Operative time was longer in LADG than in ODG (median 278 vs. 194 min, p < 0.001), while blood loss was smaller (median 38 vs. 115 ml, p < 0.001). There was no difference in the overall proportion with in-hospital grade 3-4 surgical complications (3.3 %: LADG, 3.7 %: ODG). The proportion of patients with elevated serum AST/ALT was higher in LADG than in ODG (16.4 vs. 5.3 %, p < 0.001). There was no operation-related death in either arm., Conclusions: This trial confirmed that LADG was as safe as ODG in terms of adverse events and short-term clinical outcomes. LADG may be an alternative procedure in clinical IA/IB gastric cancer if the noninferiority of LADG in terms of RFS is confirmed.

Background: A critical issue in multicenter randomized trials focusing on surgical techniques is quality control, as the quality of the surgery usually varies widely if the procedure employed is complicated. Few studies have evaluated interinstitutional variation in randomized trials in order to check not only the generalizability of the results but also the reliability of the study group itself., Methods: Two randomized phase III trials (JCOG9501 and JCOG9502) were conducted that compared standard and experimental surgery for gastric and esophagogastric junction adenocarcinomas. Mixed effects models were used to examine short- and long-term outcome data for 521 patients from 23 hospitals in JCOG9501 and 157 patients from 21 hospitals in JCOG9502., Results: In both trials, some variation was observed in the number of dissected lymph nodes, the operative time, and the volume of blood lost. Estimated 5-year overall survival after standard surgery differed among hospitals (JCOG9501, 58.0-75.1 %; JCOG9502, 49.1-58.7 %), while there was little variation in the hazard ratio for overall survival (OS) for experimental versus standard surgery (JCOG9501, 1.05-1.48; JCOG9502, 1.44-1.48). Higher hospital gastrectomy volume was significantly correlated with a lower proportion of postoperative complications in JCOG9501 (ρ = -0.524, P = 0.010) and reduced blood loss in JCOG9502 (ρ = -0.442, P = 0.045). OS was not correlated with hospital or surgeon volume., Conclusions: There was some degree of interinstitutional variation in outcomes after standard surgery, but there was little variation in the hazard ratio for OS for experimental surgery, indicating that the final conclusions of the two randomized phase III trials can be generalized to their respective target populations.

Background: Gastric cancer with extensive lymph node metastasis is commonly considered unresectable, with a poor prognosis. We previously reported the results of the use of cisplatin and S-1 as preoperative chemotherapy for gastric cancer with extensive lymph node metastasis; docetaxel, cisplatin, and S-1 (DCS) have now been investigated for the same purpose., Methods: Patients received two or three 28-day cycles of DCS therapy (docetaxel at 40 mg/m 2 and cisplatin at 60 mg/m 2 on day 1, S-1 at 40 mg/m 2 twice daily for 2 weeks) followed by gastrectomy with D2 plus para-aortic nodal dissection. After R0 resection, S-1 chemotherapy was given for 1 year. The primary end point was the response rate (RR) to preoperative chemotherapy determined by central peer review according to the Response Evaluation Criteria in Solid Tumors version 1.0. The planned sample size was 50, with one-sided alpha of 10 %, power of 80 %, expected RR of 80 %, and threshold of 65 %., Results: Between July 2011 and May 2013, 53 patients were enrolled, of whom 52 were eligible. The clinical RR was 57.7 % [30/52, 80 % confidence interval 47.9-67.1 %, p = 0.89], and R0 resection was achieved in 84.6 % of patients (44/52). Common grade 3 or grade 4 adverse events during DCS therapy were leukocytopenia (18.9 %), neutropenia (39.6 %), and hyponatremia (15.1 %). The common grade 3 or grade 4 surgical morbidity was abdominal infection (10.2 %). The pathological RR was 50.0 % (26/52)., Conclusions: Preoperative DCS therapy was feasible but did not show a sufficient RR. Preoperative cisplatin and S-1 therapy is still considered the tentative standard treatment for this population until survival results are known.

Objective: To clarify the role of splenectomy in total gastrectomy for proximal gastric cancer., Backgrounds: Splenectomy in total gastrectomy is associated with increased operative morbidity and mortality, but its survival benefit is unclear. Previous randomized controlled trials were underpowered and inconclusive., Methods: We conducted a multiinstitutional randomized controlled trial. Proximal gastric adenocarcinoma of T2-4/N0-2/M0 not invading the greater curvature was eligible. During the operation, surgeons confirmed that R0 resection was possible with negative lavage cytology, and patients were randomly assigned to either splenectomy or spleen preservation. The primary endpoint was overall survival (OS) and the secondary endpoints were relapse-free survival, operative morbidity, operation time, and blood loss. The trial was designed to confirm noninferiority of spleen preservation to splenectomy in OS with a noninferiority margin of the hazard ratio as 1.21 and 1-sided alpha of 5%., Results: Between June 2002 and March 2009, 505 patients (254 splenectomy, 251 spleen preservation) were enrolled from 36 institutions. Splenectomy was associated with higher morbidity and larger blood loss, but the operation time was similar. The 5-year survivals were 75.1% and 76.4% in the splenectomy and spleen preservation groups, respectively. The hazard ratio was 0.88 (90.7%, confidence interval 0.67-1.16) (<1.21); thus, the noninferiority of spleen preservation was confirmed (P = 0.025)., Conclusions: In total gastrectomy for proximal gastric cancer that does not invade the greater curvature, splenectomy should be avoided as it increases operative morbidity without improving survival.

Background: This randomized phase II study compared weekly administration of paclitaxel (wPTX) with the best available 5-fluorouracil (5-FU) regimen as second-line treatment for advanced gastric cancer patients with severe peritoneal metastasis refractory to fluoropyrimidine., Methods: In the best available 5-FU arm, continuous infusion of 5-FU (800 mg/m(2)/day, days 1-5, every 4 weeks) was given to patients with prior chemotherapy including bolus 5-FU, and methotrexate and 5-FU sequential bolus injection (methotrexate at 100 mg/m(2) followed by bolus 5-FU at 600 mg/m(2) with leucovorin, weekly) was given to those who had previously received continuous infusion of 5-FU or oral administration of fluoropyrimidine. In the wPTX arm, paclitaxel (80 mg/m(2)) was administered on days 1, 8, and 15, every 4 weeks. This study adopted a screening design (one-sided α = 30 %) with the primary end point of overall survival., Results: One hundred patients were randomized to the 5-FU arm (n = 49) or the wPTX arm (n = 51). Although the median survival time was 7.7 months in both arms, the 2-year survival rates were 2.9 % in the 5-FU arm and 9.1 % in the wPTX arm [hazard ratio 0.89 (95 % confidence interval 0.57-1.38), one-sided p = 0.298}. The median progression-free survival was longer with wPTX than with 5-FU [3.7 months vs 2.4 months; hazard ratio 0.58 (95 % confidence interval 0.38-0.88), one-sided p = 0.005]. The incidences of grade 4 neutropenia, grade 3/4 febrile neutropenia, diarrhea, and treatment-related death were 6 %, 4 %, 10 %, and 2 %, respectively, in the 5-FU arm and 2 %, 0 %, 0 %, and 0 %, respectively, in the wPTX arm., Conclusions: As second-line chemotherapy, wPTX appears feasible and promising. This regimen can be included in a test arm in future phase III trials for treatment of advanced gastric cancer with severe peritoneal metastasis.

Background: Chemotherapy is the standard of care for incurable advanced gastric cancer. Whether the addition of gastrectomy to chemotherapy improves survival for patients with advanced gastric cancer with a single non-curable factor remains controversial. We aimed to investigate the superiority of gastrectomy followed by chemotherapy versus chemotherapy alone with respect to overall survival in these patients., Methods: We did an open-label, randomised, phase 3 trial at 44 centres or hospitals in Japan, South Korea, and Singapore. Patients aged 20-75 years with advanced gastric cancer with a single non-curable factor confined to either the liver (H1), peritoneum (P1), or para-aortic lymph nodes (16a1/b2) were randomly assigned (1:1) in each country to chemotherapy alone or gastrectomy followed by chemotherapy by a minimisation method with biased-coin assignment to balance the groups according to institution, clinical nodal status, and non-curable factor. Patients, treating physicians, and individuals who assessed outcomes and analysed data were not masked to treatment assignment. Chemotherapy consisted of oral S-1 80 mg/m(2) per day on days 1-21 and cisplatin 60 mg/m(2) on day 8 of every 5-week cycle. Gastrectomy was restricted to D1 lymphadenectomy without any resection of metastatic lesions. The primary endpoint was overall survival, analysed by intention to treat. This study is registered with UMIN-CTR, number UMIN000001012., Findings: Between Feb 4, 2008, and Sept 17, 2013, 175 patients were randomly assigned to chemotherapy alone (86 patients) or gastrectomy followed by chemotherapy (89 patients). After the first interim analysis on Sept 14, 2013, the predictive probability of overall survival being significantly higher in the gastrectomy plus chemotherapy group than in the chemotherapy alone group at the final analysis was only 13·2%, so the study was closed on the basis of futility. Overall survival at 2 years for all randomly assigned patients was 31·7% (95% CI 21·7-42·2) for patients assigned to chemotherapy alone compared with 25·1% (16·2-34·9) for those assigned to gastrectomy plus chemotherapy. Median overall survival was 16·6 months (95% CI 13·7-19·8) for patients assigned to chemotherapy alone and 14·3 months (11·8-16·3) for those assigned to gastrectomy plus chemotherapy (hazard ratio 1·09, 95% CI 0·78-1·52; one-sided p=0·70). The incidence of the following grade 3 or 4 chemotherapy-associated adverse events was higher in patients assigned to gastrectomy plus chemotherapy than in those assigned to chemotherapy alone: leucopenia (14 patients [18%] vs two [3%]), anorexia (22 [29%] vs nine [12%]), nausea (11 [15%] vs four [5%]), and hyponatraemia (seven [9%] vs four [5%]). One treatment-related death occurred in a patient assigned to chemotherapy alone (sudden cardiopulmonary arrest of unknown cause during the second cycle of chemotherapy) and one occurred in a patient assigned to chemotherapy plus gastrectomy (rapid growth of peritoneal metastasis after discharge 12 days after surgery)., Interpretation: Since gastrectomy followed by chemotherapy did not show any survival benefit compared with chemotherapy alone in advanced gastric cancer with a single non-curable factor, gastrectomy cannot be justified for treatment of patients with these tumours., Funding: The Ministry of Health, Labour and Welfare of Japan and the Korean Gastric Cancer Association., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Pre-operative chemotherapy with S-1 plus cisplatin is considered to be acceptable as one of the standard treatment options for gastric cancer patients with extensive lymph node metastases in Japan. Addition of trastuzumab to chemotherapy is shown to be effective for HER2-positive advanced gastric cancer patients, and we have commenced a randomized Phase II trial in March 2015 to evaluate S-1 plus cisplatin plus trastuzumab compared with S-1 plus cisplatin alone in the neoadjuvant setting for HER2-positive gastric cancer patients with ELM, which are followed by adjuvant chemotherapy with S-1 for 1 year. A total of 130 patients will be accrued from 41 Japanese institutions over 3 years. The primary endpoint is overall survival. The secondary endpoints are progression-free survival, response rate of pre-operative chemotherapy, proportion of patients with R0 resection, proportion of patients who complete the pre-operative chemotherapy and surgery, proportion of patients who complete the protocol treatment including post-operative chemotherapy, pathological response rate and adverse events. This trial has been registered in the UMIN Clinical Trials Registry as UMIN 000016920., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Human epidermal growth factor receptor 2 (HER2) is likely overexpressed and/or amplified in locally advanced gastric cancer with extensive (bulky N2 or paraaortic) lymph node metastasis, and patients may benefit from treatment with anti-HER2 antibodies. This study evaluated the frequency of HER2 overexpression and amplification in The Japanese Gastric Cancer Association (JGCA)-N3 and JGCA-bulky N2 tumors and the correlation between HER2 status and survival., Methods: HER2 status was assessed using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in tumor tissue samples from 89 patients with gastric adenocarcinoma enrolled in the phase II JCOG0001 and JCOG0405 trials. HER2 positivity was defined as IHC3+ or IHC2+ with confirmatory FISH results., Results: Of the 89 tumor samples, 24 (27 %) showed HER2 positivity, including 16 scored as IHC3+ and 8 as IHC2+ and FISH positive. Multivariate analysis showed that the HER2 positivity rate was significantly higher in evaluable differentiated tumors than in undifferentiated tumors [18/44 (40.9 %) vs. 5/42 (11.9 %)]. Although the apparent OS curve of HER2 positive was superior to that of HER2 negative patients, HER2 status was not a statistically significant prognostic factor in multivariate analysis., Conclusion: The HER2 positivity rate was relatively high in patients with JGCA-bulky N2 and JGCA-N3 gastric adenocarcinoma, suggesting that HER2 evaluation is essential to select the therapeutic regimen for neoadjuvant chemotherapy for this group of patients.

Background: Pathological response rate (pathRR) is a common endpoint used to assess the efficacy of preoperative therapy for gastric cancer. PathRR is estimated based on the percentage of the residual tumor area in the primary tumorous bed. Various cutoff definitions used in previous trials (e.g., 10, 33, 40, 50, 67 %) often impair the comparability of pathRRs between trials., Methods: Individual patient data were used from four JCOG trials evaluating preoperative chemotherapy (JCOG0001, JCOG0002, JCOG0210, JCOG0405). Pathological specimens were evaluated from 173 out of 188 patients (92 %) who underwent surgery. Residual tumor area and primary tumorous beds were traced on a virtual microscopic slide by one pathologist and another confirmed these areas. The hazard ratio (HR) in overall survival was calculated for each cutoff percentage by stratified Cox regression analysis, including the study as a stratification factor, and concordance probability estimates (CPE) were calculated., Results: The numbers of patients with 0%, 1-10 %, 11-33 %, 34-50 %, 51-66 %, and 67-100 % residual tumors were 8, 35, 33, 27, 23, and 47, respectively. HRs in 10, 33, 50, and 67 % cutoffs were 1.91, 1.70, 1.55, and 1.71 for the overall population, and CPEs were 0.56, 0.56, 0.55, and 0.55, respectively. In patients with R0 resection, HRs in 10, 33, 50, and 67 % cutoffs were 1.87, 1.54, 1.24, and 1.38, and CPEs were 0.56, 0.55, 0.52, and 0.52. In subgroup analyses, the 10 % cutoff did not predict survival well for type 4 (linitis plastica) tumors., Conclusions: The 10 % cutoff should be the global standard cutoff of %residual tumor to determine pathRR. PathRR might not be recommended for clinical trials where the main subjects are type 4 tumors.