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Background Improvements in early detection and treatment have resulted in an increasing number of long-term survivors of colorectal cancer (CRC). For the survivors, second primary cancer and recurrence are important issues; however, evidence for an appropriate surveillance strategy remains limited. This study aimed to investigate the frequency and timing of second primary cancer in patients after surgery for exploring an appropriate surveillance strategy by using an integrated analysis of three large-scale randomized controlled trials in Japan. Methods The eligibility criteria of three trials included histologically confirmed CRC and having received surgery. The timing, site and frequency of second primary cancers and recurrence were investigated. Risk factors associated with second primary cancers were also examined. The standardized incidence ratio (SIR) of second primary cancers compared with the national database of the Japan Cancer Registry was estimated. Results A total of 2824 patients were included in this study. The cumulative incidence of second primary cancer increased over time. The SIR of any second primary cancer was 1.07 (95% CI: 0.94–1.21). The SIR for second primary cancers of colon was 1.09 (95% CI: 0.79–1.47). The cumulative incidence of recurrence almost reached plateau at 3 years. Conclusions A common surveillance strategy for the general population can be applied even for curatively resected CRC patients, as the risk of second primary cancers was almost the same as that of the general population.

Purpose Computed tomography of the abdomen and pelvis is a useful imaging modality for identifying origin and extent of ovarian cancer before primary debulking surgery. However, the International Federation of Gynecology and Obstetrics staging for ovarian cancer is determined based on surgico-pathological findings. The purpose of this study is to determine whether computed tomography staging can be the surrogate for surgico-pathological International Federation of Gynecology and Obstetrics staging in advanced ovarian cancer undergoing neoadjuvant chemotherapy. Methods Computed tomography staging was compared with surgico-pathological International Federation of Gynecology and Obstetrics staging in primary debulking surgery arm patients in a randomized controlled trial comparing primary debulking surgery and neoadjuvant chemotherapy (JCOG0602). The cancer of primary debulking surgery arm was identically diagnosed regarding the origin and extent with the cancer of neoadjuvant chemotherapy arm before accrual, using imaging studies (computed tomography and/or magnetic resonance imaging), cytological examination (ascites, pleural effusion or tumor contents fluid) and tumor marker (CA125 > 200 U/mL and CEA < 20 ng/mL). Institutional computed tomography staging was also compared with computed tomography staging by central review. Results Among 149 primary debulking surgery arm patients, 147 patients who underwent primary debulking surgery immediately were analyzed. Positive predictive values and sensitivity of computed tomography staging for surgical stage III disease (extra-pelvic peritoneal disease and/or retroperitoneal lymph node metastasis) were 99%. Meanwhile, positive predictive values for the presence of small (≤2 cm) extra-pelvic peritoneal disease were low; Conclusions Preoperative computed tomography staging in each institution can be the surrogate for surgico-pathological diagnosis in stage III disease of ovarian cancer patients undergoing neoadjuvant chemotherapy without diagnostic surgery, but reliability of diagnosis of stage IIIB disease is inadequate. Clinical trial registration: UMIN000000523(UMIN-CTR).

Although gastric cancer is one of the Lynch syndrome (LS)-related tumors, the clinicopathological features of gastric cancer in patients with LS remain uncertain. To investigate the incidence risk and clinicopathological features of gastric neoplasms in LS, we conducted a retrospective cohort study in Japanese LS patients. LS patients with pathogenic mismatch repair (MMR) gene variants were extracted from the LS registry of the National Cancer Center Hospital, Japan. Cumulative risks of gastric neoplasm, including dysplasia and cancer, were estimated using the Kaplan–Meier method. Gastric atrophy was evaluated endoscopically and/or histologically. Immunohistochemical staining for MMR proteins was performed for all available specimens. Of 118 eligible patients, 26 patients were diagnosed with 58 gastric neoplasms. The cumulative incidence of gastric neoplasm was 41.0% (95% confidence interval, 26.9–55.0) at the age of 70. Of these, 13 (50%) patients developed synchronous and/or metachronous multiple gastric neoplasms. Among the 49 gastric neoplasms available for detailed pathological evaluation, all were associated with intestinal metaplasia. Immunohistochemically, 42 (86%) were MMR-deficient. The individuals with gastric atrophy had a significantly higher risk of developing gastric neoplasms compared with those without gastric atrophy (26 cases/54 individuals vs. 0 cases/53 individuals) (P = 0.026). LS patients, particularly those with atrophic gastritis, are at high risk of gastric neoplasm and often develop multiple tumors. Endoscopic surveillance for gastric cancer is recommended for LS patients, especially those with atrophic gastritis.

Summary We conducted a randomised phase II study to determine the optimal dose and schedule of melphalan, prednisone, and bortezomib (MPB) (jRCTs031180097). Transplant‐ineligible untreated multiple myeloma patients were randomised to Arm A (twice weekly bortezomib in one six‐week cycle followed by eight five‐week cycles of four times once weekly bortezomib with melphalan and prednisolone on days 1–4) or Arm B (nine four‐week cycles of three times once weekly bortezomib with melphalan and prednisolone on days 1–4). The primary end‐point was complete response (CR) rate. Of 91 patients randomised to two arms, 88 were eligible. The median cumulative bortezomib doses were 45·8 and 35·1 mg/m2, CR rate was 18·6% [95% confidence interval (CI) 8·4–33·4] and 6·7% (95% CI 1·4–18·3), and the median progression‐free survival (PFS) was 2·5 and 1·4 years in Arms A and B [hazard ratio (HR) 1·93 (95% CI 1·09–3·42)], respectively. Frequent grade ≥3 haematologic toxicities in Arms A and B were neutropenia (64·4% vs. 28·3%) and thrombocytopenia (35·6% vs. 10·9%). Grade 2/3 peripheral neuropathy was observed in 24·4/2·2% in Arm A and 8·7/0% in Arm B. In conclusion, Arm A was the more promising regimen, suggesting that the twice weekly schedule of bortezomib in the first cycle and higher cumulative dose of both bortezomib and melphalan influences the efficacy of modified MPB.

Regarding the comparison between primary debulking surgery (PDS) and neoadjuvant chemotherapy (NACT) for stage III/IV ovarian, tubal and peritoneal cancers, EORTC55971 and CHORUS studies demonstrated noninferiority of NACT. Previously, we reported reduced invasiveness of NACT in JCOG0602. This is a final analysis including the primary endpoint of overall survival (OS).Patients were randomised to PDS (PDS followed by 8x paclitaxel and carboplatin, i.e. TC regimen) or NACT (4x TC, interval debulking surgery [IDS], 4x TC). The primary endpoint was OS. The noninferiority hazard ratio (HR) margin for NACT compared with PDS was 1·161. The planned sample size was 300.Between 2006 and 2011, 301 patients were randomised, 149 to PDS and 152 to NACT. The median OS was 49·0 and 44·3 months in the PDS and NACT. HR for NACT was 1·052 [90·8% confidence interval (CI) 0·835-1·326], and one-sided noninferiority p-value was 0·24. Median progression-free survival was 15·1 and 16·4 months in the PDS and NACT (HR: 0·96 [95%CI 0·75-1·23]). In the PDS arm, 147/149 underwent PDS and 49/147 underwent IDS. In the NACT arm 130/152 underwent IDS. Complete resection was achieved in 12% (17/147) of PDS and 31% (45/147) of PDS ± IDS in the PDS arm and in 64% (83/130) of IDS in the NACT arm. Optimal surgery (residual tumour1 cm) was achieved in 37% (55/147), 63% (92/147), and 82% (107/130 respectively. In the NACT, PS 2/3, serum albumin ≤2·5, CA125 2000 an institution with low study activity was advantageous, whereas clear/mucinous histology was disadvantageous for OS.The noninferiority of NACT was not confirmed. NACT may not always be a substitute for PDS. However, as our study had smaller numbers, the noninferiority of the previous studies cannot be denied.Ministry of Health, Labour and Welfare, Japan and the National Cancer Center, Japan.UMIN000000523.

541 Background: Relapse after highly invasive surgery for biliary tract cancers (BTCs), especially in the early postoperative period, causes medical, psychological, social, and economic disadvantages to the patients. However, approximately 30% of patients with curatively resected BTCs experience relapse within the first 12 months. JCOG1202 (UMIN000011688) is a randomized phase III trial conducted in patients with resected BTCs showing the benefit of adjuvant S-1 for overall survival. This study aimed to investigate the risk factors for early relapse of resected BTCs in the JCOG1202 cohort. Methods: Of the 440 patients enrolled in the JCOG1202, 217 patients who received surgery alone (arm A) and 207 patients who received adjuvant S-1 (arm B) were eligible and included in this analysis. Early relapse was defined as relapse or death within 12 months after enrollment. Predictive factors for early relapse were assessed using logistic regression analyses. Results: Postoperative early relapse was observed in 59 (27.2%) and 38 (18.4%) of patients in arm A and arm B, respectively. In multivariable logistic regression analysis for the 424 eligible patients, postoperative CA19-9 levels >37 u/ml (odds ratio (OR): 2.790, 95% confidence interval (CI): 1.262-6.170), poorly differentiation (vs. well-differentiated/papillary) (OR: 4.746, 95% CI:1.927-11.688), moderate differentiation (vs. well-differentiated/papillary) (OR: 1.955, 95% CI:1.071-3.567), lymph node metastases > 4 (vs. 0) (OR: 3.991, 95% CI: 1.674-9.514), lymph node metastases 1-3 (vs. 0) (OR: 2.661, 95% CI: 1.471-4.814), and presence of residual tumor (OR: 2.171, 95% CI: 1.070-4.408) were independent risk factors for early relapse. Importantly, adjuvant S-1 chemotherapy significantly reduced early relapse (OR: 0.491, 95% CI: 0.290-0.833). Similar results were observed in arm B. Conclusions: Postoperative CA19-9 level, tumor differentiation, lymph node metastases, and the residual tumor significantly impact early relapse in patients with curatively resected BTCs. Although adjuvant S-1 chemotherapy was effective in reducing early relapse, similar factors tended to be the risk factors in patients receiving adjuvant S-1 chemotherapy. Patients at high risk of early relapse may need more intensive perioperative therapy. Clinical trial information: UMIN000011688 .

TPS621 Background: Biliary tract cancer (BTC) is a highly lethal disease. The prognosis remains poor even after macroscopically curative resection due to the high recurrence rate. Therefore, developing effective adjuvant therapy is essential to improve treatment outcomes. In 2021, a phase III trial (JCOG1202: ASCOT) showed the superiority of adjuvant S-1 chemotherapy to surgery alone in the overall survival (OS) in BTC patients with curative resection (hazard ratio [HR] 0.694, 95% confidence interval [CI]: 0.514–0.935; p=0.008). Consequently, adjuvant S-1 chemotherapy has become the standard of care for resected BTC. In contrast, only a few studies have been conducted to assess the effectiveness of neoadjuvant therapy for BTC until now. Recently, a phase III trial (KHBO1401-MITSUBA) demonstrated the superiority of gemcitabine + cisplatin + S-1 (GCS) therapy to gemcitabine + cisplatin in patients with advanced unresectable BTC in terms of OS (HR 0.79, 90% CI: 0.628–0.996; p=0.046). The GCS arm showed a high response rate (41.5%), with promise in a neoadjuvant setting. This phase III trial aims to confirm the superiority of neoadjuvant GCS to surgery first in patients with resectable BTC. Methods: The main eligibility criteria are: (1) histologically diagnosed with adenocarcinoma or adenosquamous carcinoma; (2) diagnosed as resectable BTC with clinical stage II–IVA for perihilar bile duct cancer, stage IB–III for distal bile duct cancer, stage IIIA–IVA for gallbladder cancer, stage IIA–III for ampullary cancer, or stage III–IVA/stage IVB (T4N1M0) for intrahepatic bile duct cancer by diagnostic imaging; (3) Eastern Cooperative Oncology Group Performance Status 0 or 1; and (4) age ≥20 years. Enrolled patients are randomized 1:1 to neoadjuvant GCS + surgery + adjuvant S-1 or surgery + adjuvant S-1 regarding the center and primary site (perihilar/distal/gall bladder/ampulla of Vater/intrahepatic) by the minimization method. The GCS regimen comprises gemcitabine (1000 mg/m2) and cisplatin (25 mg/m2) on day 1 and S-1 (80-120 mg/day) on days 1–7, every 2 weeks for 3 courses. After surgery, S-1 (80-120 mg/day) for 4 weeks-on, 2 weeks-off, for a total of 4 cycles, is administered in both arms. The primary endpoint is OS, and secondary endpoints are progression-free survival (PFS), OS and PFS in patients who underwent R0/R1 resection, incidence of non-resection, %R0 resection, %R0/R1 resection, %lymph node metastasis, postoperative complications of Clavien–Dindo Grade IIIa or severer, serious adverse events, and objective response rate in the GCS arm. We calculated a sample size of 330 patients to obtain 70% power at a one-sided alpha error of 5%, a hazard ratio of 0.698 (3-year OS 67% vs 75.6%), an accrual period of 5 years, and a follow-up period of 3 years. The patient accrual was started in March 2021, and 126 patients have been enrolled as of September 2022. Clinical trial information: jRCTs031200388 .

OBJECTIVES S-1 monotherapy with concurrent radiotherapy (RT) is a standard of care for patients with locally advanced pancreatic cancer (LAPC). Although renal dysfunction increases S-1 monotherapy toxicity, its effect in S-1 with concurrent RT remains unknown. We evaluated the effect of renal function on the safety of S-1 with RT for LAPC. METHODS We performed an integrated exploratory post hoc analysis of data from 2 prospective studies (JCOG1106 and LAPC-S1RT), where patients with LAPC received RT (50.4 Gy/28 fraction for 5.5 weeks) and concurrent S-1 (40 mg/m2 per dose, twice daily on the day of irradiation). We split the patients into high creatinine clearance (CCr; ≥80 mL/min) and low CCr (

BACKGROUND/AIM To maximize the effect of perioperative chemotherapy in breast cancer, it is critical to keep the relative dose intensity (RDI) high. While bi-weekly doxorubicin and cyclophosphamide, dose-dense AC (ddAC), instead of tri-weekly conventional AC (cAC) followed by a taxane has been adopted as standard perioperative chemotherapy, postponement or discontinuation are sometimes experienced during ddAC or subsequent taxane phase. This study aimed at evaluating whether ddAC, compared to cAC, was associated with reduced RDI. PATIENTS AND METHODS We compared ddAC and cAC, both followed by a taxane, for perioperative breast cancer regarding the proportion of completion of planned treatment (%completion), defined as an RDI ≥85% for both AC and taxane phases. RESULTS There was no remarkable difference between the groups in patient characteristics after propensity score matching (n=46 in ddAC, and n=86 in cAC). The %completion was similar between the groups (67.4% vs. 65.1%). Most other endpoints related to RDI were similar between groups. The incidence of pneumonia was higher in the ddAC group (13% vs. 3%) including one Pneumocystis jiroveci pneumonia. CONCLUSION ddAC followed by a taxane can be considered with sufficient supportive measures and precautions for pneumonia.

There are few reports on the technical difficulty of gastric endoscopic submucosal dissection (ESD). The aim of this study was to investigate the factors associated with the technical difficulty of ESD for early gastric cancer (EGC) using the data from the multicenter non-randomized confirmatory trial of expanded indication criteria of ESD (JCOG0607).The major inclusion criteria were as follows: (1) histologically proven intestinal-type adenocarcinoma; (2) cT1aN0M0; (3) lesion without finding of ulcer (UL-negative) with 2 cm in size, or UL-positive with ≤ 3 cm; (4) age 20-75 years. The difficult case was defined as ESD taking ≥ 120 min, piecemeal resection, and/or developing perforation during procedure.Between June 2007 and October 2010, 470 patients were enrolled from 29 institutions. Median procedure time was 79 (range 14-462) min, and it was ≥ 120 min in 127 patients. Twelve patients developed perforation during ESD, and the procedure time was ≥ 120 min in 9 of them. Therefore, 130 patients (27.7%) were identified as difficult cases. Multivariable analysis showed that UL-negative with 5 cm (vs. UL-negative with ≤ 3 cm, odds ratio, 24.993; 95% CI 6.130-101.897, p 0.0001) had the largest odds ratio and followed by UL-negative with 3-5 cm upper or middle portion of stomach and age ≤ 60 years were significantly associated with difficulty.UL-negative lesion with 3 cm, upper or middle portion of stomach and age ≤ 60 years were independent factors associated with technical difficulty of ESD for EGC. Trial registered number was UMIN000000737.

While endoscopic submucosal dissection (ESD) is recognized as a minimally invasive standard treatment for differentiated early gastric cancers (EGCs), it has not been indicated for undifferentiated EGC (UD-EGC) because of a relatively high risk of lymph node metastasis (LNM). However, patients with surgically resected mucosal (cT1a) UD-EGC ≤ 2 cm in size with no lymphovascular invasion or ulceration are reported to be at a very low risk of LNM. This multicenter, single-arm, confirmatory trial was conducted to evaluate the efficacy and safety of ESD for UD-EGC. The key eligibility criteria were endoscopically diagnosed cT1a/N0/M0, single primary lesion, size ≤ 2 cm, no ulceration and histologically proven components of undifferentiated adenocarcinoma on biopsy. Based on the histological findings after ESD, additional gastrectomy was indicated if the criteria for curative resection were not satisfied. The subjects of the primary analysis were patients with UD-EGC as the dominant component. The primary endpoint was 5-year overall survival (OS) of patients with UD-EGC. Three hundred 46 patients were enrolled from 49 institutions. The proportion of en bloc resection was 99%. No ESD-related Grade 4 adverse events were noted. Delayed bleeding and intraoperative and delayed perforation occurred in 25 (7.3%), 13 (3.8%), and 6 (1.7%) patients, respectively. Among the 275 patients who were the subjects of the primary analysis, curative resection was achieved in 195 patients (71%), and 5-year OS was 99.3% (95% CI: 97.1–99.8). ESD can be a curative and less invasive treatment for UD-EGC for patients meeting the eligibility criteria of this study.

Everolimus is recognized as one of the standard drugs for the treatment of unresectable or recurrent gastroenteropancreatic neuroendocrine tumors (NET). However, recent evidence has suggested that addition of somatostatin analogs to everolimus may yield better survival outcomes as compared to everolimus alone. In April 2020, we have initiated a randomized phase III trial in Japan, to confirm the superiority of combined everolimus plus lanreotide therapy over everolimus monotherapy in patients with unresectable or recurrent gastroenteropancreatic NETs with poor prognostic factors (Ki-67 labeling index: LI 5%-20% or Ki-67 LI

The overall survival of SBRT for T2N0M0 NSCLC was 67.9% at 3 years and 40.8% at 5 years with low toxicity., Purpose A dose escalation study to determine the recommended dose with stereotactic body radiation therapy (SBRT) for peripheral T2N0M0 non-small cell carcinomas (JCOG0702) was conducted. The purpose of this paper is to report the survival and the late toxicities of JCOG0702. Materials and methods The continual reassessment method was used to determine the dose level that patients should be assigned to and to estimate the maximum tolerated dose. The starting dose was 40 Gy in four fractions at D95 of PTV. Results Twenty-eight patients were enrolled. Ten patients were treated with 40 Gy at D95 of PTV, four patients with 45 Gy, eight patients with 50 Gy, one patient with 55 Gy and five patients with 60 Gy. Ten patients were alive at the last follow-up. Overall survival (OS) for all patients was 67.9% (95% CI 47.3–81.8%) at 3 years and 40.8% (95% CI 22.4–58.5%) at 5 years. No Grade 3 or higher toxicity was observed after 181 days from the beginning of the SBRT. Compared to the toxicities up to 180 days, chest wall related toxicities were more frequent after 181 days. Conclusions The 5-year OS of 40.8% indicates the possibility that SBRT for peripheral T2N0M0 non-small cell lung cancer is superior to conventional radiotherapy. The effect of the SBRT dose escalation on OS is unclear and further studies are warranted.

JCOG0909 is a phase II trial of definitive chemoradiotherapy including salvage treatment for cStage II–III thoracic esophageal cancer; the radiation field for elective regional lymph node irradiation, which can affect patient outcome and adverse event, varied based on the primary tumor site, i.e., upper (Ut), middle (Mt), and lower thoracic (Lt) esophagus. The impact of different primary sites on the safety and efficacy of definitive chemoradiotherapy in JCOG0909 is not well characterized. Patients were categorized into three groups (Ut, Mt, and Lt) according to the primary tumor location. We compared acute adverse events during definitive chemoradiotherapy, complete response (CR) rate, 3-year progression-free survival (PFS), and overall survival (OS) among the 3 groups. Out of the 96 patients enrolled in JCOG0909 between April 2010 and August 2014, 94 patients (16, 59, and 19 patients in the Ut, Mt, and Lt groups, respectively) were included in this exploratory analysis. The proportion of patients with cStage III was 25% in the Ut, 37% in the Mt, and 47% in the Lt group. Grade 3–4 leukopenia, neutropenia, and thrombocytopenia were more frequently observed in the Mt (66%, 54%, and 15%) and Lt groups (84%, 68%, and 16%) than in the Ut group (38%, 44%, and 0%). There was no significant between-group difference with respect to 3-year OS (73.3%, 77.9%, and 57.9%), 3-year PFS (60.0%, 59.3%, and 47.4%), or CR rate (62.5%, 62.7%, and 42.1%). In JCOG0909, the incidence of severe hematological toxicity had a trend toward higher in the Mt and Lt than the Ut esophageal cancer; however, no remarkable difference by primary sites was observed with respect to efficacy endpoints.

Objectives To explore the risk factors of laryngo-esophageal dysfunction-free survival and nutritional support dependence over 12 months in patients with unresectable locally advanced head and neck carcinomas who received chemoradiotherapy in a phase II trial of JCOG0706 (UMIN000001272). Methods Forty-five patients received radiation therapy for a total of 70 Gy/35fr concurrently with S-1 and cisplatin. Risk factors of laryngo-esophageal dysfunction-free survival and nutritional support dependence over 12 months were analyzed using Cox regression models and logistic regression models, respectively, with consideration to patient laboratory data just before chemoradiotherapy. Radiation fields were reviewed to analyze the relationship between the extent of the irradiated field and functional outcome. Results With a median follow-up period of 3.5 years, 3-year laryngo-esophageal dysfunction-free survival was 48.9%. For laryngo-esophageal dysfunction-free survival, hazards ratio of 2.35 in patients with nutritional support at registration (vs. without nutritional support; 95% confidence interval 0.96–5.76). For nutritional support dependence over 12 months, odds ratio was 6.77 in patients with hemoglobin less than the median of 13.4 g/dl (vs. higher than or equal to the median; 95% confidence interval 1.24–36.85) and was 6.00 in patients with albumin less than the median of 3.9 g/dl (vs. higher than or equal to the median; 95% confidence interval 1.11–32.54). Primary sites in disease-free patients with nutritional support dependence over 12 months were the oropharynx (N = 2) or hypopharynx (N = 1), and all pharyngeal constrictor muscles were included in irradiated fields with a curative dose. Conclusions This supplementary analysis showed that pretreatment severe dysphagia requiring nutritional support, anemia and hypoalbuminemia might have a negative prognostic impact on long-term functional outcomes after curative chemoradiotherapy in head and neck cancer.

TPS4654 Background: Biliary tract cancer (BTC) is one of the most lethal cancers with limited treatment options. Early clinical trials showed a hint of activity of HER2 blockade for HER2 positive BTC, the prevalence of which was reported to be from 5% to 20%. Trastuzumab deruxtecan (DS-8201) is an antibody-drug conjugate composed of an anti-HER2 antibody, cleavable terapeptide-based linker, and a topoisomerase I inhibitor, which showed durable response in HER2 positive breast cancer as well as in a wide spectrum of cancer subtypes in a phase I study. In addition, preclinical research demonstrated the effectiveness of trastuzumab deruxtecan for HER2 positive BTC patient derived xenograft model. This phase II study is being conducted to evaluate the efficacy and safety of trastuzumab deruxtecan for HER2 positive BTC. Methods: The main inclusion criteria are unresectable or recurrent BTC, histologically diagnosed as adenocarcinoma or adenosquamous carcinoma, confirmed HER2-expressing status by central pathological examination, refractory or intolerant to treatment including gemcitabine, and adequate organ function. Patients are registered and receive 5.4 mg/kg trastuzumab deruxtecan every 3 weeks until disease progression or unacceptable toxicities. Primary endpoint is the overall response rate (ORR) in HER2 positive (defined as IHC3+, or IHC2+/ISH+; ISH+ defined as HER2/ CEP17 ≥2.0) patients by central imaging review. The ORR in all HER2-expressing patients (including HER2 low expressing defined as IHC/ISH status of 0/+, 1+/-, 1+/+, or 2+/-), progression-free survival, overall survival, and incidence of adverse events are assessed as secondary endpoints. Thirty-two patients will be enrolled, including 24 with HER2 positive BTC as primary cohort and 8 with HER2 low expressing BTC. The study has 80% power for primary endpoint in HER2 positive BTC patients, with one-sided alpha error of 5%; threshold ORR of 15% and expected ORR of 40%. Pharmacokinetics and circulating tumor DNA analyses serially are performed. The study was initiated in May 2019 with enrollment ongoing. A total of 15 patients were enrolled as of January 2020. Funding: Japan Agency for Medical Research and Development, and Daiichi Sankyo. Clinical trial information: JMA-IIA00423 .

4545 Background: Definitive chemoradiotherapy (dCRT) consisting of 5-fluorouracil (5-FU) and cisplatin (CDDP) with 60 Gy radiotherapy (RT) for clinical (c) Stage II/III esophageal carcinoma (EC) is a standard treatment for patients (pts) refusing surgery (S) in Japan based on the previous trial (JCOG9906). However, poor survival, high incidence of late toxicities, and severe complications of salvage S are problems. We conducted a single-arm confirmatory study of CRT modifications including salvage treatment (ST) to reduce CRT toxicities and facilitate ST to improve survival. We reported the 3-year survival at 2018 ASCO Annual Meeting. We report the final data after 5-year follow-up. Methods: EC pts with cStage II/III (UICC 6th, non-T4), PS 0-1, and age 20-75 years were eligible. Chemotherapy (CT) was CDDP (75 mg/m2 on days 1, 29) and 5-FU (1000 mg/m2/d on days 1-4, 29-32). RT was administered to a total dose of 50.4 Gy with elective nodal irradiation of 41.4 Gy. Good responders after dCRT received additional 1-2 cycles of CT. For residual or recurrent disease, salvage endoscopic resection (ER) or S was performed based on the prespecified criteria. Planned sample size was 95, with one-sided alpha of 5% and power of 80%, expected and threshold 3-year overall survival (OS) as 55% and 42%. Key secondary endpoint was ST related toxicity. Final analysis was planned after 5-year follow-up for all pts. Results: From 4/2010 to 8/2014, 96 pts were enrolled, two were ineligible and 94 were included in efficacy analysis (cStage IIA/IIB/III, 22/38/34). Complete response was achieved in 55 pts (59%). Salvage ER and S were performed in 5 (5%) and 27 pts (29%). R0 resection of salvage S was achieved in 23 (85%). With a median follow-up of 5.95 years, 3- and 5-year OS was 74.2% (90% CI 65.9-80.8%) and 64.5% (95% CI 53.9-73.3%). 5-year progression-free survival and esophagectomy-free survival were 48.3% (95% CI 37.9-58.0%) and 54.9% (95% CI 44.3-64.4%). 5-year OS after salvage S was 31.0% and hazard ratio of R1-2 to R0 was 5.635 (95% CI: 1.818-17.467). No complications occurred after salvage ER. Five pts (19%) showed ≥ grade 3 operative complications and 1 treatment related death due to bronchus-pulmonary artery fistula occurred after salvage S. Only 9 pts (9.6%) showed grade 3 late toxicities. And no late operative complications more than grade 3 were observed. Conclusions: This combined modality treatment of dCRT with ST showed acceptable toxicities, favorable 5-year survival, and promising esophageal preservation. Clinical trial information: jRCTs031180110 .

3538 Background: Although regorafenib significantly improved overall survival compared with placebo for patients with metastatic colorectal cancer (mCRC) refractory to standard chemotherapies in the global phase III CORRECT trial, regorafenib is often discontinued due to toxicity. Lenvatinib is an inhibitor of VEGF receptors 1–3, FGF receptors 1–4, PDGF receptors α, RET, and KIT, showing receptor inhibition profile and kinetics different from regorafenib. This phase II study was conducted to evaluate the efficacy and safety of lenvatinib in patients with mCRC refractory to standard chemotherapies. Methods: mCRC patients with measurable lesions, PS 0-1, and refractory to standard chemotherapies including fluoropyrimidine, oxaliplatin, irinotecan, bevacizumab, cetuximab or panitumumab (if RAS wild-type), and TAS-102 (trifluridine/tipiracil) were eligible. Prior treatment with regorafenib was not allowed. Patients received lenvatinib orally at a dose of 24 mg once daily in 28-day cycles until unacceptable toxicity or disease progression. The primary endpoint was disease control rate (DCR) assessed by independent central review. Secondary endpoints included safety, response rate, progression-free survival (PFS), and overall survival. The planned sample size was 30 patients to expect a DCR of 60% with a threshold DCR of 35%, one-sided alpha of 5% and power of 80%. Results: Between October 2016 to January 2018, 30 patients were enrolled. All had received prior chemotherapy; 14 (47%) and 16 (53%) had received 3 or ≥ 4 prior lines for advanced disease, respectively. The median number of lenvatinib cycles was 4 (range 1-13). Two patients achieved partial response and 19 patients had stable disease, resulting in a response rate of 6.7% and DCR of 70.0% (95% CI: 50.6-85.3%). Median PFS was 3.6 months (95% CI: 2.6-3.7). The most common grade ≥ 3 adverse events were hypertension (53%), elevated serum aspartate aminotransferase (13%), thrombocytopenia (10%), and anorexia (7%) without unexpected safety signals. Conclusions: Lenvatinib showed promising antitumor activity with acceptable toxicity for patients with mCRC refractory to standard chemotherapies. Clinical trial information: UMIN000023446.

301 Background: S-1 is an oral agent consisting of a mixture of tegafur which is a prodrug of 5-fluorouracil (5-FU), 5-chloro-2,4-dihydroxypyrimidine (DHP) and potassium oxonate. Serum concentration of 5-FU increases in case of renal dysfunction due to decrease of DHP excretion into urine. The aim of this study was to evaluate the influence of renal function to the efficacy and safety of S-1 with concurrent radiotherapy (RT) for locally advanced pancreatic cancer (LAPC). Methods: This study was an integrated exploratory analysis of JCOG1106 and LAPC- S1RT, in which pts with LAPC received RT (50.4Gy/28 fr over 5.5 weeks) and concurrent S-1 (40 mg/m2/dose, bid. on the day of irradiation). Eligibility criteria for this study were pts who received both irradiation and S-1 at least once without induction chemotherapy, and who had creatinine clearance (CCr) ≥ 50 ml/min at the time of registration. We assigned pts into high (≥ 80 ml/min) and low (< 80 ml/min) CCr groups. The primary endpoint was the incidence of ≥ Grade 3 adverse reactions (ARs). Secondary endpoints were the incidence of ≥ Grade 2 gastrointestinal ARs (GI-ARs) defined as anorexia, nausea, vomiting, diarrhea and mucositis oral, relative dose intensity of S-1, CA19-9 response, progression-free survival, and overall survival. Results: Fifty and 59 pts were included in this study from JCOG1106 and LAPC-S1RT, respectively. Median age was 65 years old (range: 31–80), and 57 pts were male. Median CCr was 80.4 ml/min. High CCr group included 57 pts and the median was 97.5 ml/min (range 80.0–194.6), and low CCr group included 52 pts and the median was 64.4 ml/min (range 50.0–78.3). Low CCr group tended to have more ≥ Grade 3 ARs and ≥ Grade 2 GI-ARs compared to high CCr group (30.8% vs. 15.8% and 51.9% vs. 36.8%). However, no evident tendencies were observed in other secondary endpoints. Multivariable analysis showed risk ratio of low CCr group for ≥ G3 ARs was 1.493 [95% CI: 0.710–3.145], although risk ratio of females was 2.486 [95% CI: 1.043–5.924]. Conclusions: Our study indicated that renal dysfunction may increase adverse reactions in the treatment of S-1 with concurrent RT for LAPC, and we should pay attention to renal function and consider for dose reduction.

349 Background: JCOG1113 is a randomized phase III trial to confirm the non-inferiority of gemcitabine plus S-1 (GS) to gemcitabine plus cisplatin (GC) for advanced biliary tract cancer (BTC) in overall survival (OS). In the final analysis, GS demonstrated non-inferiority to GC in OS and was considered as a new option of standard of care for advanced BTC. However, there are few reports on the efficacy and safety of combination chemotherapy in elderly patients with advanced BTC. Therefore, this study aimed to explore the clinical outcomes of combination chemotherapy in elderly patients with advanced BTC. Methods: Among all enrolled patients in JCOG1113, ≥ 75 years old patients were included in this exploratory subgroup analysis. Cox regression analysis was performed to investigate the influence of age at baseline on OS and PFS. Clinically relevant adverse events (AEs) were defined as any of grade 2 or more fatigue, appetite loss, nausea, vomiting, oral mucositis, and diarrhea, and were compared using Fisher’s exact test. Results: Among all enrolled patients, 155 patients in GC and 139 patients in GS were included in < 75 years old cohort and 20 patients in GC and 40 patients in GS were included in ≥ 75 years old cohort.The HR of ≥ 75 years old cohort to < 75 years old cohort for OS was 0.96 (95% CI 0.71–1.30) in all enrolled patients. The HR of ≥ 75 years old cohort to < 75 years old cohort for OS was 1.26 (95% CI 0.77–2.04) in GC, and 0.84 (95% CI 0.56–1.24) in GS. The HR of ≥ 75 years old cohort to < 75 years old cohort for PFS was 1.01 (95% CI 0.63–1.61) in GC, and 0.78 (95% CI 0.54–1.12) in GS. Clinically relevant AEs were 36.1% in < 75 years old cohort and 25.0% in ≥ 75 years old cohort in GC, and 29.5% in < 75 years old cohort and 32.5% in ≥ 75 years old cohort in GS. Conclusions: The clinical outcomes of combination chemotherapy in elderly patients were comparable to non-elderly patients. Clinical trial information: 000010667.

TPS179 Background: Tumor mutational burden (TMB) is an emerging biomarker for immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC). Analysis of circulating tumor DNA (ctDNA) has been reported to effectively identify patients likely to respond to ICIs by effectively and non-invasively evaluating the TMB in the tumor in NSCLC and gastric cancer. Methods: We are conducting an investigator-initiated multicenter phase II basket trial to investigate efficacy and safety of nivolumab monotherapy in patients with advanced gastrointestinal (GI) cancers with high bTMB identified by ctDNA analysis as part of the Nationwide Cancer Genome Screening Project (SCRUM-Japan GI-SCREEN). Eligibility criteria include histologically confirmed unresectable or recurrent GI malignancies; ECOG PS of 0 or 1; refractory or intolerant to the standard therapies; and high bTMB identified by a 73-gene sequencing ctDNA panel (Guardant360) regardless of microsatellite instability status. Patients will be enrolled into one of four disease-specific cohorts (colorectal, gastric, esophageal, and other GI cancer cohort), and receive intravenous nivolumab monotherapy of 360 mg every 3 weeks. The bTMB score is calculated by adjustment of mutation count by tumor fraction, and tentative bTMB level cut-offs were determined according to objective response rate (ORR) reported for ICI treatment for each tumor subtype in previous trials. The trial will utilize a two-stage design with a Bayesian hierarchical model, and tentative bTMB level cut-off will be re-assessed in the first stage. Primary endpoint in each stage is the disease control rate at 6 week and the ORR assessed by investigators per RECIST v1.1, respectively. Target sample size is determined as 70 in total so that the statistical power in each disease-specific cohort calculated based on a Bayesian posterior distribution attains 70 to 80% with one-sided alpha level in each cohort of approximately 10%. For biomarker analysis, tumor tissue and ctDNA will be serially collected and analyzed by whole-exome, transcriptome, and T cell receptor sequencing. This trial was initiated since September 2018. Clinical trial information: UMIN000033182.

368 Background: JCOG1113 is a randomized phase III trial to evaluate gemcitabine (GEM) plus S-1 (GS) versus GEM plus cisplatin (GC) regarding overall survival (OS) for advanced biliary tract cancer (BTC) (UMIN000001685) and the non-inferiority of GS was demonstrated. It is necessary to consider renal function using cisplatin or S-1 because cisplatin has renal toxicity, and the toxicity of S-1 is affected by renal function. Therefore, we evaluated the influence of renal function on the efficacy and safety of GC and GS in JCOG1113. Methods: All enrolled patients (pts) in JCOG1113 (n = 354) were analyzed. Eligibility criteria included chemotherapy-naïve pts with recurrent or unresectable biliary tract adenocarcinoma, ECOG-PS of 0–1, CCr > 50 ml/min, and adequate organ function. Renal function was classified into two groups by creatinine clearance (CCr) as calculated by the Cockcroft-Gault formula; high CCr (CCr ≥ 80 ml/min) or low CCr (80 > CCr ≥ 50 ml/min). The impact of renal function on OS and progression-free survival (PFS) were compared using the Cox regression model. The adverse events (AEs) were compared using Fisher’s exact test. Results: Eighty-eight pts on GC and 88 pts on GS were included in the high CCr group, and 87 pts on GC and 91 pts on GS were included in the low CCr group. There were no differences between the groups regarding, sex, PS, primary site, biliary drainage, operation, or recurrence, except for age. The hazard ratio (HR) of GS to GC for OS was 1.12 (95% CI 0.81–1.56) in the high CCr group and 0.80 (95% CI 0.58–1.11) in the low CCr group. The HR of GS to GC for PFS was 1.06 (95% CI 0.78–1.44) in the high CCr group and 0.69 (95% CI 0.50–0.94) in the low CCr group. Grade 3-4 AEs of white blood cell count decreased (35.3%/23.6%), anemia (29.4%/7.9%) and platelet count decreased (18.8%/10.1%) were more common in GC than GS in the low CCr group. In contrast, the incidence of all grade 3-4 non-hematological AEs was higher (36.0%/11.8%) in GS than GC in the low CCr group ( p = 0.0002). Conclusions: GS was better in terms of OS, PFS, and hematological toxicities than GC in the low CCr group. GS might be recommended for the population with lower renal function in the treatment for advanced BTC.

104 Background: JCOG0909, a single-arm confirmatory trial of definitive chemoradiotherapy (dCRT) including salvage treatment, demonstrated promising efficacy and safety for cStage II/III (UICC-TNM 6th) esophageal cancer (EC) (Ito Y, ASCO 2018). Radiation (RT) fields included the elective regional lymph node during initial 41.4 Gy, such as bilateral supraclavicular fossae and superior mediastinal lymph nodes for upper thoracic (Ut), and mediastinal and perigastric lymph nodes for middle thoracic (Mt)/lower thoracic (Lt) EC. It is unclear whether the safety and efficacy are associated with the tumor location in patients with cStage II/III EC treated with dCRT. Methods: Patients who were enrolled in JCOG0909 and underwent dCRT were analyzed. Patients were categorized into three groups according to primary tumor location (Ut/Mt/Lt). We compared adverse events during dCRT, complete response (CR) rate, progression-free survival (PFS) and overall survival (OS) among groups. Results: Ninety-four patients (Ut/Mt/Lt: 16/59/19) were analyzed. The proportions of cStage IIA/IIB/III were 31%/44%/25% in Ut group, 20%/42%/37% in Mt group, and 21%/32%/47% in Lt group, respectively. The summary of safety and efficacy was listed in Table 1. Grade 3-4 leukopenia, neutropenia and thrombocytopenia were more frequently observed in Mt and Lt groups than in Ut group. CR rate was 63% in Ut, 63% in Mt, and 42% in Lt, respectively. 3-year PFS in Ut/Mt/Lt was 60%/59%/47% and 3-year OS was 73%/78%/58%, respectively. Conclusions: The RT field by the tumor location might be associated with efficacy and safety of dCRT for cStage II/III esophageal cancer. [Table: see text]

Background: CHOP plus rituximab (R-CHOP) is the standard of care for previously untreated DLBCL. R-CHOP comprises CHOP and one-dose rituximab in each 21-day cycle; however, the schedule of rituximab administration has not been fully optimized. Dose-dense rituximab was expected to increase its peak concentration to enhance the synergistic effect with chemotherapy at early phase of treatment. To compare weekly administration of rituximab combined with CHOP (RW-CHOP) with standard R-CHOP in patients with previously untreated DLBCL, we conducted a multicenter, randomized phase II/III study (JCOG0601, UMIN000000929). Methods: Previously untreated patients with CD20+ DLBCL were eligible. Other major inclusion criteria were as follows: aged 20-79 years; ECOG performance status 0-2, at least 1 measurable lesion and preserved organ functions. At the beginning of the study, patients with advanced stage disease and the low or low-intermediate risk group by the International Prognostic Index (IPI) were eligible. These criteria were amended in September 2010 to allow enrollment of the patients with any IPI risk and any clinical stage because of slow accrual. Patients were randomly assigned to standard R-CHOP (rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, vincristine 1.4 mg/m2 [max 2 mg], all IV on day 1, and prednisone 100 mg/day PO [40mg/m2 for aged >65] on days 1-5, every 3 weeks) or RW-CHOP (standard CHOP with eight doses of weekly rituximab [375mg/m2 IV on days1, 8, 15, 22, 29, 36, 43 and 50]). Six cycles of CHOP were given in stage I non-bulky patients, 8 cycles were given in stage I bulky and II-IV patients, and rituximab was given 8 times regardless of cycles of CHOP. Randomization was stratified by institution, presence or absence of bulky mass and patient age. The primary endpoint of phase III part was progression-free survival (PFS). Secondary endpoints included overall survival (OS) and adverse events (AE). Assuming 3-year PFS in the R-CHOP arm to be 77% and expecting a 7% increase in 3-year PFS of the RW-CHOP arm, required sample size was 211 per arm with a one-sided alpha of 5%, power of 80%, an accrual period of 7 years, and a follow-up period of 3 years. Results: Between December 2007 and December 2014, a total of 422 patients were randomized to study treatments but primary analysis was performed in 421 patients: 213 to the R-CHOP arm and 208 to the RW-CHOP arm, because of one consent withdrawal. Baseline characteristics of 421 eligible patients were as follows (R-CHOP vs. RW-CHOP): median age, 61 vs. 62 years; male sex, 54.5% vs. 55.8%; Ann Arbor stage I/II/III/IV, 14.6/32.9/26.8/25.8% vs. 16.3/42.8/20.2/20.7%; and IPI score ≤2, 77.0% vs. 87.5%. With a median follow-up of 63.4 months (range: 3.2-119.2) among all patients, there was no significant difference in PFS between the arms (hazard ratio [HR], 0.95; 90.6% confidence interval [CI], 0.68 to 1.31; one-sided log-rank P = 0.39). The 3-year PFS and OS were 79.2% and 88.7% with the R-CHOP arm and 80.3% and 90.4% with the RW-CHOP arm, respectively. The complete response rate and overall response rate were 77.0% and 93.0% in the R-CHOP arm and 82.2% and 91.8% in the RW-CHOP arm, respectively. Major AEs were hematological toxicities and infections. Grade (G) 3/4 neutropenia and G 3/4 thrombocytopenia were observed in 97.7% and 8.0% in the R-CHOP arm and 97.1% and 5.3% in the RW-CHOP arm, respectively. G3 febrile neutropenia was occurred in 33.8% in the R-CHOP arm and in 22.1% in the RW-CHOP arm. The frequency of severe AE was 2.3% in the R-CHOP arm and 3.8% in the RW-CHOP arm. Safety profile was comparable. No unexpected AEs were experienced. Conclusion: In combination of standard CHOP and rituximab, dose-dense weekly rituximab at early phase of treatment did not improve the PFS in patients with untreated DLBCL. Figure. Figure. Disclosures Ohmachi: Celgene: Honoraria; Takeda Pharmaceutical Co., Ltd,: Honoraria; Pfizer: Honoraria; Chugai Pharma: Honoraria; Kyowa Hakko Kirin: Honoraria; Eisai: Honoraria; Janssen: Honoraria; Meiji Pharma: Honoraria. Kinoshita:Takeda: Honoraria; Takeda: Research Funding; Ono: Research Funding; MSD: Research Funding; Solasia: Research Funding; Janssen: Honoraria; Ono: Honoraria; Zenyaku: Research Funding; Eisai: Research Funding; Gilead: Research Funding. Tobinai:Kyowa Hakko Kirin: Honoraria, Research Funding; Zenyaku Kogyo: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; Ono Pharmaceutical: Honoraria, Research Funding; Eisai: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Chugai Pharma: Honoraria, Research Funding; HUYA Bioscience International: Consultancy, Honoraria; SERVIER: Research Funding; Abbvie: Research Funding. Fukuhara:Sumitomo Dainippon: Research Funding; Solasia: Research Funding; Symbio: Research Funding; Sanofi: Research Funding; Pfizer: Research Funding; Otsuka Pharmaceutical: Research Funding; Ono: Honoraria, Research Funding; Novartis pharma: Research Funding; Nippon-shinyaku: Research Funding; MSD: Research Funding; Mundipharma: Honoraria, Research Funding; Mitsubishi Tanabe: Research Funding; Kyowa Hakko Kirin: Honoraria, Research Funding; Japan Blood Products Organization: Research Funding; Janssen: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; Eisai: Honoraria, Research Funding; Boehringer Ingelheim: Research Funding; Daiichi-Sankyo: Research Funding; Chugai: Research Funding; Celgene: Research Funding; Baxalta: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Bayer Yakuhin: Research Funding; Alexionpharma: Research Funding; AbbVie: Research Funding; Astellas: Research Funding; Nihon Ultmarc: Research Funding; Taiho: Research Funding; Teijin Pharma: Research Funding; Zenyaku Kogyo: Honoraria, Research Funding; Takeda: Honoraria. Uchida:Takeda Pharmaceutical: Honoraria; Chugai Pharmaceutical: Honoraria; Kyowa Hakko Kirin: Honoraria; Meiji Seika Pharma: Honoraria; Bristol-Myers Squibb: Honoraria; Pfizer: Honoraria; Nippon Shinyaku: Honoraria; Novartis: Honoraria; Teijin: Honoraria; Celgene: Honoraria; Mundipharma: Honoraria; Janssen Pharma: Honoraria; Otsuka Pharmaceutical: Honoraria; Eisai: Honoraria. Yamamoto:Solasia Pharma: Research Funding; Bristol-Myers Squibb: Honoraria; Novartis: Honoraria, Research Funding; ARIAD Pharmaceuticals: Research Funding; Bayer: Research Funding; Celgene: Honoraria, Research Funding; Eisai: Honoraria, Research Funding; Ono: Consultancy, Honoraria, Research Funding; AbbVie: Research Funding; Boehringer Ingelheim: Consultancy; Chugai: Consultancy, Honoraria, Research Funding; Meiji Seika Pharma: Consultancy; MSD: Research Funding; Takeda: Honoraria, Research Funding; Zenyaku: Research Funding; Kyowa Hakko Kirin: Honoraria; Otsuka: Honoraria; Pfizer: Honoraria; Sumitomo Dainippon: Honoraria; Mundipharma: Consultancy, Honoraria; HUYA: Honoraria; SymBio: Research Funding; Gilead Sciences: Research Funding. Miyazaki:Kyowa Hakko Kirin,: Honoraria, Research Funding; Celgene: Honoraria; Chugai Pharma,: Honoraria, Research Funding; Sumitomo Group: Research Funding; Nippon Shinyaku: Research Funding; Takeda: Research Funding; Astellas Pharma: Research Funding; Shionogi Pharmaceutical: Research Funding; Daiichi Sankyo: Research Funding; Eisai: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Teijin Pharma: Research Funding; Ono Pharmaceutical: Research Funding; Toyama Chemical Co: Research Funding; Mochida Pharmaceutical Co. Ltd.: Research Funding; Novo Nordisk: Research Funding. Tsukamoto:Kyowa-Kirin: Research Funding; Pfizer: Research Funding; Chugai: Research Funding; Eisai: Research Funding. Iida:Teijin Pharma: Research Funding; Toyama Chemical: Research Funding; Ono: Consultancy, Honoraria, Research Funding; Kyowa-Hakko Kirin: Research Funding; Chugai: Research Funding; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Astellas: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Gilead: Research Funding; MSD: Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Sanofi: Consultancy. Yoshida:Taiho Pharma: Honoraria; Takeda Pharma: Honoraria; Celegene: Honoraria; Chugai Pharma: Honoraria, Research Funding; Kyowa Hakko Kirin: Honoraria, Research Funding. Masaki:Ono: Research Funding; Kyowa Hakko Kirin: Research Funding; Phizer: Research Funding; Astellas: Research Funding; Eisai: Research Funding. Yakushijin:Mundipharma Co.,: Research Funding; Chugai Co.,: Research Funding; Kyowa-kirin Co.,: Research Funding; Merch Sharp & Dohme Corp.,,: Research Funding; Daiichi-Sankyo Inc.,: Research Funding; Eisai Co.: Research Funding. Suehiro:Kyowa Hakko Kirin: Research Funding; Ono Pharmaceutical: Research Funding; Chugai Pharmaceutical: Research Funding; Takeda Pharmaceutical: Research Funding. Nosaka:Bristol-Myers Squibb: Honoraria; Ono Pharmaceutical Co.LTD.: Honoraria; Eisai Co. Ltd.,: Honoraria; Kyowa Kirin Pharmaceutical Development, Inc.,: Honoraria; Chugai Pharmaceutical Co.LTD.,: Honoraria; Celgene Co. LTD.,: Honoraria. Dobashi:Celgene Co.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co. Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Sysmex Co.: Research Funding. Kuroda:Chugai Pharma: Honoraria, Research Funding. Takamatsu:Taisho Toyama Pharmaceutical: Research Funding; TAIHO Pharmaceutical: Research Funding; Pfizer: Research Funding; Bristol-Myers Squibb: Research Funding; Ono Pharmaceutical: Research Funding; Astellas Pharma: Research Funding; Kyowa Hakko Kirin: Research Funding; Chugai Pharma: Research Funding; Takeda Pharmaceutical: Research Funding; Celgene: Honoraria. Maruyama:Ono Pharmaceutical: Honoraria, Research Funding; Fujifilm: Honoraria, Research Funding; Kyowa Hakko Kirin: Honoraria, Research Funding; Asahi Kasei Pharma: Honoraria; AstraZeneca: Research Funding; Solasia Pharma: Research Funding; Pfizer: Research Funding; Nippon Boehringer Ingelheim: Research Funding; Dai-Nippon-Sumitomo: Honoraria; Dai-ichi-Sankyo: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Eisai: Honoraria, Research Funding; Biomedis International: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Chugai Pharma: Honoraria, Research Funding; MSD: Honoraria, Research Funding; Novartis: Research Funding; Otsuka: Research Funding; Amgen Astellas BioPharma: Research Funding; Zenyaku Kogyo: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; Abbvie: Research Funding; Astellas Pharma: Research Funding; Mundipharma International: Honoraria, Research Funding. Ando:Eisai: Research Funding; Meiji Seika Pharma: Research Funding; Takeda Pharmaceutical: Research Funding; Kyowa Hakko Kirin: Research Funding; Japan Blood Products Organization: Research Funding. Ishizawa:Eisai: Honoraria; Janssen: Honoraria; Chugai: Honoraria; Celgene: Honoraria; Otsuka: Research Funding; Sanofi: Research Funding; Phizer: Research Funding. Ogura:Celltrion: Consultancy, Research Funding; Mundi Pharma: Consultancy; SymBio: Research Funding; Takeda: Honoraria; Cellgene: Honoraria; MeijiSeika Pharma: Consultancy. Hotta:SymBio: Consultancy; CellSeed Inc.: Membership on an entity's Board of Directors or advisory committees. Tsukasaki:Celgene: Honoraria; Eisai: Research Funding; Chugai Pharma: Honoraria, Research Funding; HUYA: Consultancy, Research Funding; Ono Pharma: Consultancy; Daiich-Sankyo: Consultancy; Mundy Pharma: Honoraria; Kyowa-hakko/Kirin: Honoraria; Seattle Genetics: Research Funding. Nagai:HUYA Bioscience International: Research Funding; Chugai Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Ono Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Gilead Sciences Inc.: Honoraria, Research Funding; Bayer Yakuhin Ltd.: Research Funding; Sanofi K. K.: Honoraria; Zenyaku Kogyo Co., Ltd.: Honoraria, Research Funding; Solasia Pharma K.K.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Roche Ltd.: Honoraria; Esai Co., Ltd.: Honoraria, Research Funding; Takeda Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; SymBio Pharmaceuticals Limited: Research Funding; Janssen Pharmaceutical K.K.: Honoraria, Research Funding; Kyowa Hakko Kirin Co., Ltd.: Honoraria, Research Funding; Mundipharma K.K.: Honoraria, Research Funding; AstraZeneca plc.: Research Funding; Abbvie G. K.: Research Funding.

4023Background: For clinical stage I submucosal (cT1b-SM) ESCC, surgery is the standard treatment and CRT is optional. We conducted a single-arm confirmatory study of diagnostic ER plus selective C...

561 Background: Improvements in early detection and treatment have resulted in an increasing number of long-term survivors of colorectal cancer (CRC). For the survivors, Second primary cancers and recurrence are important issues, but the evidence for appropriate surveillance strategy is limited. The aim of this study was to investigate the frequency and the timing of second primary cancers and recurrence in patients (pts) after surgery using 3 randomized trials (J0205, J0212 and J0404) conducted by Colorectal Cancer Study Group of JCOG. Methods: Eligibility criteria included histologically proven CRC and having received surgery. The timing, site and frequency of second primary cancer and recurrence were investigated. Risk factors associated with the events were explored. Standardized incidence ratio (SIR) about second primary cancer compared with national database of Japan Cancer Registry was estimated. Results: A total of 2,824 pts with a median follow-up time of 6 years were included. Median age was 62 years old (23-75), male/female was 58%/42%, and stage 0/I/II/III/IV was 0.2%/8.7%/25.4%/64.8%/0.9%. Pts with 5-FU based adjuvant chemotherapy were 63%. Cumulative incidence of second primary cancer increased constantly over time (Table). Among 240 pts, the most common site was lung (37), stomach (35) and colon (32). In multivariable analysis, age (over 64 years old) and sex (male) were risk factors (age HR: 1.60 (95% CI: 1.24-2.07), sex HR: 1.36 (95% CI: 1.04-1.78)). The SIR of any second primary cancers was 1.07 (95% CI: 0.94-1.21). The SIR for second primary cancers of colon was 1.09 (95% CI: 0.79-1.47). On the other hand, cumulative incidence of recurrence almost reached at 3 years. Conclusions: Common surveillance strategy can be applied even for curatively resected CRC pts after 3 years from surgery, because the risk of second primary cancer was almost same as general population over time. The necessity of intensive follow-up to detect recurrence decreases after 3 years. [Table: see text]