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Abstract Aim The Japanese National Clinical Database, which covers more than 95% of the surgeries performed in Japan, is the largest nationwide database. This is the 2021 annual report of the Gastroenterological Section of the National Clinical Database, which aims to present the short‐term outcomes of cases registered in 2021 and discuss significant changes and insights into gastroenterological surgeries observed over the decade. Methods We reviewed the data of patients registered in the National Clinical Database between 2012 and 2021. Results In total, 5 788 093 cases, including 597 780 cases in 2021, were extracted from the National Clinical Database. The number of surgeries resumed its original trend after a uniform decrease due to the coronavirus disease 2019 pandemic. The patient population continues to age, and the proportion of female patients is steadily increasing. The trend of surgeries being conducted in certified institutions with the involvement of board‐certified surgeons is consistently rising. Moreover, the increasing trend of endoscopic surgery rate is still maintained. Although operative mortality is declining, the trend of increasing postoperative complications continues. Surgery on the esophagus, liver, and pancreas has shown substantial improvements in operative mortality, with a high participation rate of board‐certified surgeons. Surgical procedures with a high incidence of emergency surgeries are characterized by low participation rates of board‐certified surgeons, increased morbidity rates, and worse mortality outcomes. Conclusion This overview of surgical patients in Japan, obtained using data extracted from the National Clinical Database, may serve as a critical cornerstone for the future development of gastroenterological surgery.

Abstract Aim This study aimed to evaluate the technical safety and feasibility of gastrectomy for super‐elderly patients ≥85‐y‐old with gastric cancer and to clarify the risk factors for serious postoperative complications in these patients. Methods Between 2017 and 2020, 10,203 patients who underwent distal gastrectomy (DG) and 2580 patients who underwent total gastrectomy (TG) were reviewed from the Japanese National Clinical Database. All possible preoperative factors were used to explore the risk factors for serious postoperative complications in the super‐elderly patients with gastric cancer. Results For DG, the operative mortality rate was 1.6% (162 patients), and the rate of serious postoperative complications was 7.8% (796 patients). Similarly, the mortality rate was 2.6% (67 patients), and the rate of serious complications was 11.3% (292 patients) for TG. Based on multivariate analysis, body mass index (≥25 kg/m2), activities of daily living (ADL) (partially dependent), ASA‐PS (Grade ≥3), dyspnea, ascites, history of cerebrovascular disease, serum albumin (1.2 mg/dL) in DG, and ADL (partially dependent), ASA‐PS (Grade ≥3), previous percutaneous coronary intervention, dialysis, WBC (>9000 μL), and AST (>35 IU/L) in TG were strong risk factors for serious postoperative complications. Conclusions The study findings suggest that gastrectomy for super‐elderly gastric cancer patients is relatively safe and feasible. Surgeons need to pay special attention to physical status and past medical history than tumor factors for preventing serious postoperative complications in super‐elderly gastric cancer patients.

Abstract Background The advantages of robot‐assisted minimally invasive esophagectomy (RA‐MIE) over conventional minimally invasive esophagectomy (C‐MIE) are unknown. This nationwide large‐scale study aimed to compare surgical outcomes between RA‐MIE and C‐MIE using rigorous propensity score methods, including detailed covariates and relevant outcomes. Methods This Japanese nationwide retrospective cohort study included RA‐MIE or C‐MIE for esophageal malignant tumors performed between October 2018 and December 2019 and registered in the Japanese National Clinical Database. The primary outcome measure was postoperative complications classified as Clavien–Dindo Grade IIIa or higher. Propensity score matching was performed to create a balanced covariate distribution between the two groups. Results After propensity score matching, 1092 patients were selected. The RA‐MIE group had a significantly longer operation time and greater blood loss than the C‐MIE group (565 vs. 477 min and 120 vs. 90 mL). Furthermore, the R0 resection rate was lower in the RA‐MIE group than in the C‐MIE group (95.1% vs. 97.8%). The RA‐MIE and C‐MIE groups had no differences regarding overall complications ≥ Grade IIIa (22.0% vs. 20.3%, p = 0.52), 30‐day mortality rates (0.4% vs. 0.5%), and operative mortality rates (0.7% vs. 0.7%). Deep SSI was less frequent (2.7% vs. 6.0%) and pulmonary embolism was more frequent (2.4% vs. 0.5%) in the RA‐MIE group than in the C‐MIE group. Conclusions In the initial phase of implementation, RA‐MIE and C‐MIE demonstrated comparable morbidity rates when performed by skilled board‐certified endoscopic surgeons.

Abstract Background/objectives This study aimed to evaluate the safety, efficacy, and long-term outcomes of S-1-based neoadjuvant chemoradiotherapy (NACRT) in patients with resectable or borderline-resectable pancreatic ductal adenocarcinoma (PDAC). Methods This retrospective study included patients with PDAC who underwent S-1-based NACRT at our institute between 2010 and 2017. Results Forty patients were included in the study, including 15 (37.5%) with resectable PDAC and 25 (62.5%) with borderline-resectable PDAC. The NACRT completion and resection rates were 85.0% (n = 34) and 67.5% (n = 27), respectively. Several grade 3 adverse events were observed, including leukopenia (25.0%), anorexia (17.5%), neutropenia (10.0%), thrombocytopenia (7.5%), febrile neutropenia (2.5%), elevated aspartate aminotransferase/alanine aminotransferase (2.5%) levels, and hyponatremia (2.5%). The R0 resection rate was 70.4% (n = 19/27) in patients who underwent pancreatectomy. Grades 1, 2, and 3 according to the College of American Pathologists grading system were observed in 1 (3.7%), 12 (44.4%), and 14 (51.9%) patients, respectively. Over a median follow-up period of 32.9 months (interquartile range, 9.1–68.0), the 1-, 3-, and 5-year OS rates were 81.4%, 45.5%, and 30.3%, respectively, in the intention-to-treat analysis. In the curative-intent surgery cohort (n = 27), the 1-, 3-, and 5-year OS rates were 88.9%, 48.2%, and 37.0%, respectively. Conclusions S-1-based NACRT is safe and yields acceptable long-term outcomes for patients with resectable or borderline-resectable PDAC.

Abstract Aim The coronavirus disease 2019 (COVID‐19) pandemic greatly impacted medical resources such as cancer screening, diagnosis, and treatment given to people for various diseases. We surveyed the impacts of the pandemic on the incidence of complications and mortality following pancreaticoduodenectomy for pancreatic cancer in Japan. Methods Data on patients who underwent pancreaticoduodenectomy for pancreatic cancer were extracted from the Japanese National Clinical Database (NCD) between 2018 and 2021. The number of the pancreaticoduodenectomy for pancreatic cancer were obtained and then the morbidity and mortality rates were evaluated using a standardized morbidity/mortality ratio (SMR), which is the ratio of the observed number of incidences to the expected number of incidences calculated by the risk calculator previously developed by the NCD. Results This study included 22 255 cases. The number of pancreaticoduodenectomies exhibited an increasing trend even during the COVID‐19 pandemic. The mean observed incidence rates of Grade C pancreatic fistula and Clavien–Dindo grade ≥4 complications, and the 30‐day mortality and surgical mortality rates were 0.8%, 1.8%, 0.8% and 0.9%, respectively. The standardized morbidity ratios did not increase during the COVID‐19 pandemic. The standardized mortality ratios remained within the range of variations observed before the COVID‐19 pandemic. Conclusion The increasing trend in the number of pancreaticoduodenectomies and favorable short‐term outcomes even in the COVID‐19 pandemic suggest the medical care for pancreatic cancer in Japan functioned well during the pandemic.

Abstract Background Due to the coronavirus disease 2019 (COVID‐19) pandemic, cancer screening, diagnosis, and treatment have changed. This study aimed to investigate the impact of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection prior to gastroenterological cancer surgeries on postoperative complications using data from a nationwide database in Japan. Methods Data on patients who underwent surgery for cancer including esophageal, gastric, colon, rectal, liver, and pancreatic cancer between July 1, 2019, and September 300, 2022, from real‐world sources in Japan were analyzed. The association between preoperative SARS‐CoV‐2 infection and short‐term postoperative outcomes was evaluated. A similar analysis stratified according to the interval from SARS‐CoV‐2 infection to surgery (4 weeks) was conducted. Results In total, 60 604 patients were analyzed, and 227 (0.4%) patients were diagnosed with SARS‐CoV‐2 infection preoperatively. The median interval from SARS‐CoV‐2 infection to surgery was 25 days. Patients diagnosed with SARS‐CoV‐2 infection preoperatively had a significantly higher incidence of pneumonia (odds ratio: 2.05; 95% confidence interval: 1.05–3.74; p = 0.036) than those not diagnosed with SARS‐CoV‐2 infection based on the exact logistic regression analysis adjusted for the characteristics of the patients. A similar finding was observed in patients who had SARS‐CoV‐2 infection

Abstract Aim To examine the potential negative effects of the COVID‐19 pandemic on short‐term postoperative outcomes of emergency surgery for gastroduodenal perforation in Japan. Methods A total of 7973 cases of gastroduodenal perforation from 2019 to 2021 were retrieved from the National Clinical Database (NCD), which includes >95% of surgical cases in Japan. Data were analyzed nationally and in subgroups for subjects in areas with high infection levels (HILs). Postoperative 30‐d mortality, surgical mortality, and complications (Clavien–Dindo (CD) grade ≥3) were examined. Months were considered to have significantly high or low mortality or complication rates, if the 95% confidence interval (CI) of the standardized mortality (morbidity) ratio (SMR) does not contain 1. Results Nationally, data from 2019 vs 2020 and 2021 showed 30‐d mortality of 175 (6.7%) vs 398 (7.4%), surgical mortality of 250 (9.5%) vs 537 (10.1%), and complications (CD ≥3) of 558 (21.2%) vs 1163 (21.8%). Among these data, the only significantly high SMR was found for complications in July 2020 (1.36 [95% CI: 1.001–1.80]). In areas with HILs, data from 2019 vs 2020 and 2021 indicated 30‐d mortality of 91 (6.3%) vs 215 (7.3%), surgical mortality of 135 (9.4%) vs 294 (10.0%), and complications (CD ≥3) of 304 (21.1%) vs (23.1%). In these data, no month had a significantly high SMR. Conclusion The COVID‐19 pandemic had few negative effects on outcomes after surgery for gastroduodenal perforation. These findings suggest that the emergency system for gastroduodenal perforation in Japan was generally maintained during the pandemic.

Abstract Aim Serum cholinesterase (ChE) levels are considered to reflect nutritional status. Although ChE has been well documented as a prognostic factor for some cancers, no clear consensus on its use for colorectal cancer (CRC) has been reached. The aim of this study was to investigate the relationship between preoperative serum ChE and postoperative long‐term prognosis in CRC patients. Methods A total of 1053 CRC patients who underwent curative surgery were included in this study. The correlations between the preoperative ChE value and overall survival (OS) or cancer‐specific survival (CSS) were assessed. By dividing patients into two groups according to their ChE value, OS and CSS were compared between the groups. Results Multivariate analysis revealed that the continuous ChE value was a significant predictor of OS (hazard ratio, 0.996; 95% CI, 0.993–0.998; p = 0.002) and CSS (hazard ratio, 0.994; 95% CI, 0.991–0.998; p = 0.001), independent of other variables. The low‐ChE (≤234 U/L) group had a significantly poorer prognosis than the high‐ChE (>234 U/L) group for both OS (5‐year OS for low ChE and high ChE: 79.8% and 93.3%, respectively; p

Abstract Introduction Complexities of robotic distal gastrectomy (RDG) give reason to assess physician's surgical skill. Varying levels in surgical skill affect patient outcomes. We aim to investigate how a novel artificial intelligence (AI) model can be used to evaluate surgical skill in RDG by recognizing surgical instruments. Methods Fifty‐five consecutive robotic surgical videos of RDG for gastric cancer were analyzed. We used Deeplab, a multi‐stage temporal convolutional network, and it trained on 1234 manually annotated images. The model was then tested on 149 annotated images for accuracy. Deep learning metrics such as Intersection over Union (IoU) and accuracy were assessed, and the comparison between experienced and non‐experienced surgeons based on usage of instruments during infrapyloric lymph node dissection was performed. Results We annotated 540 Cadiere forceps, 898 Fenestrated bipolars, 359 Suction tubes, 307 Maryland bipolars, 688 Harmonic scalpels, 400 Staplers, and 59 Large clips. The average IoU and accuracy were 0.82 ± 0.12 and 87.2 ± 11.9% respectively. Moreover, the percentage of each instrument's usage to overall infrapyloric lymphadenectomy duration predicted by AI were compared. The use of Stapler and Large clip were significantly shorter in the experienced group compared to the non‐experienced group. Conclusions This study is the first to report that surgical skill can be successfully and accurately determined by an AI model for RDG. Our AI gives us a way to recognize and automatically generate instance segmentation of the surgical instruments present in this procedure. Use of this technology allows unbiased, more accessible RDG surgical skill.

Abstract Aim The existing predictive risk models for the surgical outcome of acute diffused peritonitis (ADP) need renovation by adding relevant variables such as ADP's definition or causative etiology to pursue outstanding data collection reflecting the real world. We aimed to revise the risk models predicting mortality and morbidities of ADP using the latest Japanese Nationwide Clinical Database (NCD) variable set. Methods Clinical dataset of ADP patients who underwent surgery, and registered in the NCD between 2016 and 2019, were used to develop a risk model for surgical outcomes. The primary outcome was perioperative mortality. Results After data cleanup, 45 379 surgical cases for ADP were derived for analysis. The perioperative and 30‐day mortality were 10.6% and 7.2%, respectively. The prediction models have been created for the mortality and 10 morbidities associated with the mortality. The top five relevant predictors for perioperative mortality were age >80, advanced cancer with multiple metastases, platelet count of

Abstract Aim Possible negative effects of the COVID‐19 pandemic on short‐term postoperative outcomes for colorectal perforation in Japan were examined in this study. Methods The National Clinical Database (NCD) is a large‐scale database including more than 95% of surgical cases in Japan. We analyzed 13 107 cases of colorectal perforation from 2019 to 2021. National data were analyzed, and subgroup analyses were conducted for subjects in prefectures with high infection levels (HILs) and metropolitan areas (Tokyo Met. and Osaka Pref.). Postoperative 30‐day mortality, surgical mortality, and postoperative complications (Clavien–Dindo grade ≥3) were examined. Months were considered to have significantly high or low mortality or complication rates, if the 95% confidence interval (CI) of the standardized mortality (morbidity) ratio (SMR) does not contain 1. Results In the NCD, postoperative 30‐day mortality occurred in 1371 subjects (10.5%), surgical mortality in 1805 (13.8%), and postoperative complications in 3950 (30.1%). Significantly higher SMRs were found for 30‐day mortality in November 2020 (14.6%, 1.39 [95% CI: 1.04–1.83]) and February 2021 (14.6%, 1.48 [95% CI: 1.10–1.96]), and for postoperative complications in June 2020 (37.3%, 1.28 [95% CI: 1.08–1.52]) and November 2020 (36.4%, 1.21 [95% CI: 1.01–1.44]). The SMRs for surgical mortality were not significantly high in any month. In prefectures with HILs and large metropolitan areas, there were few months with significantly higher SMRs. Conclusions The COVID‐19 pandemic had limited negative effects on postoperative outcomes in patients with colorectal perforation. These findings suggest that the emergency system for colorectal perforation in Japan was generally maintained during the pandemic.

Abstract Background Anemia has negative effects on long‐term outcomes of rectal cancer patients; however, its status as a risk factor for severe complications is disputed. Perioperative risks may differ based on the severity of pre‐surgical anemia; nonetheless, no previous study has investigated these differences. This study identified risks of severe postoperative complications in rectal cancer patients based on severity of their pre‐surgical anemia. Materials and Methods This study enrolled patients who underwent low anterior resection for rectal cancer and were registered in the Japanese National Clinical Database (NCD) between 2017 and 2019. Anemia severity was categorized into three levels: mild, moderate, and severe. A logistic regression model was applied to calculate the risk‐adjusted odds ratio (OR) of severe complications after surgery. Results This study analyzed a cohort of 51 765 rectal cancer patients who underwent low anterior resection. Results showed that severe complications occurred in 10.9% of patients and were significantly more frequent in patients with anemia (13.6%) than those with normal hemoglobin levels (9.2%). Risk‐adjusted ORs of severe complications in the severe, moderate, and mild anemia groups versus the normal group for males were 1.19 (95% confidence interval [CI]: 0.89–1.58), 1.47 (1.34–1.62), and 1.21 (1.12–1.31), respectively. Those for females were 1.39 (0.90–2.15), 1.64 (1.37–1.97), and 1.36 (1.16–1.58), respectively. Conclusions According to this large cohort study, pre‐surgical anemia significantly increases the risk of severe postoperative complications in rectal cancer patients. Even mild anemia presents a significant risk.

Abstract Background The COVID‐19 outbreak made conventional medical care impossible, forcing changes in both healthcare providers and patients. In Japan, COVID‐19 infection began spreading in earnest in 2020 and exploded in 2021. There was concern that the medical impact of COVID‐19 in 2021 would differ from that in 2020. We aimed to clarify the impact of COVID‐19 on mortality and anastomotic leakage in laparoscopic surgery for gastric cancer and rectal cancer in Japan using the National Clinical Database (NCD). Methods We collected data from patients who underwent laparoscopic distal gastrectomy (LDG) and laparoscopic low anterior resection (LLAR) from January 2018 to December 2021 from the NCD, a web‐based surgical registration system in Japan. The number of surgical cases, monthly incidence of mortality and morbidity (anastomotic leakage), standardized mortality ratio (SMR), and standardized morbidity‐leakage ratio (SMLR [ratio of observed patients to expected patients calculated using the risk calculator established in the NCD]) were evaluated. Results The numbers of LDG and LLAR cases continued to decline in the first year of the pandemic in 2020 and were as low in 2021 as in 2020. Although the numbers of robot‐assisted LDG and LLAR cases increased, the growth rate was lower than the rate of increase prior to the pandemic. Mortality and anastomotic leakage, two of the most important complications, as assessed by SMR and SMLR, did not worsen during the pandemic in comparison to the pre‐pandemic period. Conclusions Laparoscopic surgeries were performed safely in Japan and were not affected by the COVID‐19 pandemic.

Abstract Aim The aim of this study was to verify the clinical feasibility of tele‐proctoring using our ultra‐low latency communication system with shared internet access. Methods Connections between two multiple remote locations at various distances were established through the TELEPRO® tele‐proctoring system. The server records the latency between the two locations for tele‐proctoring using the annotations. Questionnaires were administered to the surgeons, assistants, and medical staff. Respondents rated the quickness and quality of communication in terms of latency and disturbances in the audio, video, and usefulness of the live telestrations with annotation. Results Seven hospitals tele‐proctored with Sapporo Medical University between January 2021 and September 2022. The median latency of annotation between the two locations ranged from 24.5 to 48.5 ms. No major technological problems occurred, such as streaming interruption, loss of video or audio, poor resolution. The video encoding time was 10 ms, and its decoding time was 0.8 ms. The total latency positively correlated with the distance between two locations (R = 0.55, p

Abstract Aim We explored institutional factors in Japan associated with lower operative mortality and failure‐to‐rescue (FTR) rates for eight major gastrointestinal procedures. Methods A 22‐item online questionnaire was sent to 2119 institutional departments (IDs) to examine the association between institutional factors and operative mortality and FTR rates. IDs were classified according to the number of annual surgeries, board certification status, and locality. In addition, the top 20% and bottom 20% of IDs were identified based on FTR rates and matched with the results of the questionnaire survey. Factors associated with operative mortality were selected by multivariate analysis. Results Of the 1083 IDs that responded to the questionnaire, 568 (213 382 patients) were included in the analysis. Operative morbidity, operative mortality, and FTR rates in the top 20% and bottom 20% of IDs were 13.1% and 8.4% (p

Abstract Aim The Coronavirus Disease 2019 (COVID‐19) pandemic affected the allocation of various medical resources to several areas, including intensive care units (ICUs). However, currently, its impact on the short‐term postoperative outcomes of gastrointestinal cancer surgeries remains unclear. We aimed to evaluate the impact of the pandemic on the incidence of complications occurring after low anterior resection in patients with rectal cancer in Japan. Methods Data from the Japanese National Clinical Database between 2018 and 2021 were retrospectively examined. The primary outcome of the study was the postoperative morbidity and mortality rates before and after COVID‐19 pandemic. Moreover, the postoperative ICU admission rate was assessed. Morbidity and mortality rates were also assessed using a standardized morbidity/mortality ratio (SMR, the ratio of the actual number of incidences to the expected number of incidences calculated by the risk calculator). Results This study included 74 181 patients, including 43 663 (58.9%) from COVID‐19 epidemic areas. The mean actual incidences of anastomotic leakage (AL) and pneumonia during the study period were 9.2% and 0.9%, respectively. The SMRs of these complications did not increase during the pandemic but those of AL declined gradually. The mean 30‐day mortality and operative mortality rates were 0.3% and 0.5%, respectively. Moreover, SMRs did not change significantly in the pandemic or regional epidemic status. The ICU admission rate temporarily decreased, especially in the epidemic areas. Conclusion Although the pandemic temporarily decreased the ICU admission rate, its impact on short‐term outcomes following low anterior resection in patients with rectal cancer was insignificant in Japan.

Abstract Aim Tumor rupture has been indicated as a risk factor for recurrence of gastrointestinal stromal tumors (GISTs). The universal definition of tumor rupture was proposed. This study evaluated whether the universal definition was more accurate in identification of GISTs with high recurrent risk than subjective judgment. Methods The study included 507 patients with high‐risk GISTs who underwent complete resection between December 2012 and December 2015. We conducted a questionnaire survey in participating institutes to re‐diagnose tumor rupture based on the universal definition according to their surgical and pathological findings. We compared the clinical outcomes of tumor rupture based on the definition to those based on the surgeon's judgment and clarified the clinical importance of the rupture. Results Sixty‐four patients were initially registered to have tumor rupture by surgeon's judgment, and it became 90 patients who had tumor rupture after reevaluation. Although there were significant differences in recurrence‐free survival (RFS) between no rupture and rupture for both initial registration and reevaluation (p = 0.002,

Abstract Background The coronavirus disease 2019 (COVID‐19) pandemic had resulted in either failure to provide required medical resources or delayed treatment for gastric cancer patients. This study aimed to investigate the impact of COVID‐19 on the incidence of postoperative complications using a nationwide Japanese database of patients undergoing distal gastrectomy for gastric cancer. Methods We collected the data of patients who underwent distal gastrectomy from January 2018 to December 2021 from the National Clinical Database (NCD), a web‐based surgical registration system in Japan. The number of surgical cases, the use of intensive care units, and the incidence of morbidity per month were analyzed. We also calculated the standardized mortality ratio (SMR), defined as the ratio of the number of observed patients to the expected number of patients calculated using the risk calculator established in the NCD, for several morbidities, including pneumonia, sepsis, 30‐day mortality, and surgical mortality. Results A decrease of 568 gastrectomies was observed from April 2020 to May 2020. Although the absolute number of patients admitted to intensive care units had declined since 2020, the proportion of patients admitted to the ICU did not change before and after the pandemic. Mortality and critical morbidity (such as pneumonia and sepsis) rates were not worse during the pandemic compared to pre‐pandemic periods per the SMR. Conclusions Surgical management was conducted adequately through the organized efforts of the entire surgery department in our country even in a pandemic during which medical resources and staff may have been limited.

Abstract Aim Neoadjuvant chemoradiotherapy may improve survival in patients with advanced cholangiocarcinoma. This Phase I study aimed to determine the recommended dose of neoadjuvant chemoradiotherapy and decide whether to move to a Phase II study. Methods Patients diagnosed with resectable stage II–IVa cholangiocarcinoma were administered cisplatin (40 [level 0], 50 [level 1 as starting dose], or 60 [level 2] mg/m2), 80 mg/m2 of S‐1, and 50.4 Gy of external beam radiation. The recommended dose was defined as a dose one‐step lower than the maximum‐tolerated dose, which was defined when dose‐limiting toxicity was observed in three or more of the six patients. Results Twelve patients were eligible from November 2012 to May 2016. Ten patients had perihilar cholangiocarcinoma and two patients had distal cholangiocarcinoma. Dose‐limiting toxicity was observed in one of the first six patients at level 1 and two of the next six patients at level 2; thus, the maximum‐tolerated dose was not determined even at level 2 and the recommended dose was determined as level 2. Four patients had partial response, four patients had stable disease, and two patients had progression of disease because of liver metastases. Finally, nine patients underwent radical surgery and seven cases achieved R0 resection. However, five cases suffered biliary leakage and one suffered intrahospital death due to rupture of the hepatic artery. Conclusion We determined the recommended dose of neoadjuvant chemoradiotherapy for resectable cholangiocarcinoma. However, we terminated the trial due to a high incidence of morbidity and unexpected mortality.

Abstract Background The current standard operation for proximal gastric and gastroesophageal junction (P/GEJ) cancers with limited esophageal extension is total gastrectomy (TG). TG is associated with impaired appetite and weight loss due to the loss of gastric functions such as production of ghrelin and with anemia due to intrinsic factor loss and vitamin B12 malabsorption. Theoretically, proximal gastrectomy (PG) can mitigate these problems by preserving gastric function. However, PG with direct esophagogastric reconstruction is associated with severe postoperative reflux, delayed gastric emptying, and poor quality of life (QoL). Minimally invasive PG (MIPG) with antireflux techniques has been increasingly performed by experts but is technically demanding owing to its complexity. Moreover, the actual advantages of MIPG over minimally invasive TG (MITG) with regards to postoperative QoL are unknown. Our overall objective of this study is to determine the short-term QoL benefits of MIPG. Our central hypotheses are that MIPG is safe and that patients have improved appetite after MIPG with effective antireflux techniques, which leads to an overall QoL improvement when compared with MITG. Methods Enrollment of a total of 60 patients in this prospective survey-collection study is expected. Procedures (MITG versus MIPG, antireflux techniques for MIPG [double-tract reconstruction versus the double-flap technique]) will be chosen based on surgeon and/or patient preference. Randomization is not considered feasible because patients often have strong preferences regarding MITG and MIPG. The primary outcome is appetite level (reported on a 0-10 scale) at 3 months after surgery. With an expected 30 patients per cohort (MITG versus MIPG), this study will have 80% power to detect a one-point difference in appetite level. Patient-reported outcomes will be longitudinally collected (including questions about appetite and reflux), and specific QoL items, body weight, body mass index and ghrelin, albumin, and hemoglobin levels will be compared. Discussion Surgeons from the US, Japan, and South Korea formed this collaboration with the agreement that the surgical approach to P/GEJ cancers is an internationally important but controversial topic that requires immediate action. At the completion of the proposed research, our expected outcome is the establishment of the benefit and safety of MIPG. Trial registration This trial was registered with Clinical Trials Reporting Program Registration under the registration number NCI-2022–00267 on January 11, 2022, as well as with ClinicalTrials.gov under the registration number NCT05205343 on January 11, 2022.

Abstract Aim This study was performed to evaluate the oncological impact of surgical site infection (SSI) and pneumonia on long‐term outcomes after esophagectomy. Methods The Japan Society for Surgical Infection conducted a multicenter retrospective cohort study involving 407 patients with curative stage I/II/III esophageal cancer at 11 centers from April 2013 to March 2015. We investigated the association of SSI and postoperative pneumonia with oncological outcomes in terms of relapse‐free survival (RFS) and overall survival (OS). Results Ninety (22.1%), 65 (16.0%), and 22 (5.4%) patients had SSI, pneumonia, and both SSI and pneumonia, respectively. The univariate analysis demonstrated that SSI and pneumonia were associated with worse RFS and OS. In the multivariate analysis, however, only SSI had a significant negative impact on RFS (HR, 1.63; 95% confidence interval, 1.12–2.36; P = 0.010) and OS (HR, 2.06; 95% confidence interval, 1.41–3.01; P

Abstract Aim This study aimed to evaluate the impact of the coronavirus disease (COVID‐19) pandemic on elective endoscopic surgeries in Japan using the National Clinical Database. Methods We retrospectively analyzed the clinicopathological factors and surgical outcomes of laparoscopic cholecystectomy (LC), laparoscopic distal gastrectomy (LDG), and laparoscopic low anterior resection (LLAR) and compared the monthly numbers of each procedure performed in 2020 with those in 2018 and 2019. The degree of infection in prefectures was classified into low and high groups. Results In 2020, the number of LCs (except for acute cholecystitis) was 76 079 (93.0% of that in 2019), the number of LDGs was 14 271 (85.9% of that in 2019), and the number of LLARs was 19 570 (88.1% of that in 2019). Although the number of robot‐assisted LDG and LLAR cases increased in 2020, the growth rate was mild compared with that in 2019. There was little difference in the number of cases in the degree of infection in the prefectures. The numbers of LC, LDG, and LLAR cases decreased from May to June and recovered gradually. In late 2020, the proportion of T4 and N2 cases of gastric cancer and the number of T4 cases of rectal cancer increased compared with those in 2019. There was little difference between the proportions of postoperative complications and mortality in the three procedures between 2019 and 2020. Conclusion The number of endoscopic surgeries decreased in 2020 as a result of the COVID‐19 pandemic. However, the procedures were performed safely in Japan.

Abstract Aim Liver allografts from brain‐dead donors, which were declined and were eventually not transplanted due to accompanying marginal factors, have never been surveyed in Japan. We surveyed the declined allografts and discussed the graft potential focusing on various marginal factors. Methods We collected data on brain‐dead donors between 1999 and 2019 from the Japan Organ Transplant Network. We divided their liver allografts into declined (nontransplanted) and transplanted ones, and then characterized declined ones focusing on their timepoints of decline and accompanying marginal factors. For each marginal factor, we calculated the decline rate from the number of declined and transplanted allografts, and assessed the 1‐year graft survival rate from transplanted allografts. Results A total of 571 liver allografts were divided into 84 (14.7%) declined and 487 (85.3%) transplanted ones. In the declined allografts, a majority was declined after laparotomy (n = 55, 65.5%), most of which had steatosis and/or fibrosis (n = 52). Out of the moderate steatotic (without F ≥ 2 fibrosis) allografts (n = 33), 21 were declined and 12 were transplanted, leading to a 63.6% decline rate. The latter 12 achieved a 92.9% 1‐year graft survival rate after transplantation. Comparison of donor background showed no significant difference between the declined and transplanted allografts. Conclusion Pathological abnormalities of steatosis/fibrosis seem to be the most common donor factor leading to graft decline in Japan. Allografts with moderate steatosis were highly declined; however, transplanted ones achieved promising outcomes. This national survey highlights the potential utility of liver allografts with moderate steatosis.

Abstract Background Loss of skeletal muscle mass is a prognostic factor after surgery for gastrointestinal cancers. The treatment for perihilar cholangiocarcinoma (PHC) is a highly invasive surgery. Biliary drainage and portal vein embolization, which can prolong the preoperative waiting time (PWT), are often required before surgery. Assuming that the skeletal muscle mass can change during PWT, we investigated the clinical effect of skeletal muscle change on surgical outcomes of PHC. Methods We retrospectively reviewed the medical records of 89 patients who underwent curative surgery for PHC from January 2013 to December 2019. We defined the psoas muscle area (PMA) at the third lumbar vertebra as the skeletal muscle mass. The PMA just before surgery was divided by that at the time of diagnosis, and we defined it as the rate of change of PMA (CPMA). Patients were divided into two groups according to CPMA: wasting (n = 44, below the median CPMA) and no‐change (n = 45, above the median CPMA). Results The median PWT was 63 d, and CPMA was 96.1%. The median recurrence‐free survival and overall survival were significantly shorter in the wasting group than in the no‐change group (8.0 vs 33.2 mo, P = 0.001 and 14.2 vs 48.7 mo, P

Abstract Aim This study aimed to investigate the effect of the coronavirus disease pandemic on the number of surgeries for gastroenterological cancer cases in Japan. Methods The data recorded in the National Clinical Database of Japan between 2018 and 2020 were utilized for this study. Five specific surgeries for primary cancers and surgery for acute diffuse peritonitis were considered the primary endpoints. We divided the study period into the prepandemic and postpandemic (after April 2020) periods and examined the number of surgeries in relation to clinical factors. Results Overall, 228 860 surgeries were analyzed. Among the five primary cancer surgeries, the number of distal gastrectomies for gastric cancer decreased the most (to 81.0% of the monthly number in the prepandemic period), followed by that of low anterior resections for rectal cancer (91.4%). In contrast, the number of pancreaticoduodenectomies for pancreatic cancer increased by 7.1%, while that of surgeries for peritonitis remained stable. This trend was observed nationwide. We also noted a marked reduction in the number of distal gastrectomy (to 72.5%), low anterior resection (84.0%), and esophagectomy (88.8%) procedures for T1 tumors. The noncurative resection rate and mortalities were low despite the increased proportion of T4 tumors and older patients. Conclusion A marked reduction in surgeries for gastric and rectal cancers with early T factors may reflect prioritization of surgeries and reduction in cancer screenings. Although the quality of the surgery was maintained in terms of reduced mortalities and morbidities, the long‐term effects of this pandemic should be monitored.

Abstract Aim The National Clinical Database (NCD) of Japan is a nationwide data entry system for surgery, and it marked its 10th anniversary in 2020. The aim was to present the 2020 annual report of gastroenterological surgery of the NCD. Methods The data of the surgical procedures stipulated by the training curriculum for board‐certified surgeons of the Japanese Society of Gastroenterological Surgery in the NCD from 2011 to 2020 were summarized. Results In total, 5 622 845 cases, including 593 088 cases in 2020, were extracted from the NCD. The total number of gastroenterological surgeries increased gradually in these 10 years, except for the year 2020 due to the COVID‐19 pandemic. The annual number of surgeries of each organ, except the pancreas and liver, decreased by 0.4%–13.1% in 2020 compared to 2019. The surgical patients were consistently aging, with more than 20% of all gastroenterological surgeries in 2020 involving patients aged 80 years or older. The participation of board‐certified surgeons increased for each organ (75.9%–95.7% in 2020). The rates of endoscopic surgery also increased constantly. Although the incidences of postoperative complications of each organ increased by 0.7%–7.9% in these 10 years, postoperative mortality rates decreased by 0.2%–1.5%. Conclusions We present here the short‐term outcomes of each gastroenterological operative procedure in 2020. This review of the 10‐years of NCD data of gastroenterological surgery revealed a consistent increase of the number of surgeries (except for in 2020), especially endoscopic procedures, and aging of the Japanese population. The good safety of Japanese gastroenterological surgeries was also indicated.

Abstract Aim To investigate the impact of postoperative infection (PI), surgical site infection, and remote infection (RI), on long‐term outcomes in patients with colorectal cancer (CRC). Methods The Japan Society for Surgical Infection conducted a multicenter retrospective cohort study involving 1817 curative stage I/II/III CRC patients from April 2013 to March 2015. Patients were divided into the No‐PI group and the PI group. We examined the association between PI and oncological outcomes for cancer‐specific survival (CSS) and overall survival (OS) using Cox proportional hazards models and propensity score matching. Results Two hundred and ninety‐nine patients (16.5%) had PIs. The 5‐year CSS and OS rates in the No‐PI and PI groups were 92.8% and 87.6%, and 87.4% and 83.8%, respectively. Both the Cox proportional hazards models and propensity score matching demonstrated a significantly worse prognosis in the PI group than that in the No‐PI group for CSS (hazard ratio: 1.60; 95% confidence interval: 1.10‐2.34; P = .015 and P = .031, respectively) but not for OS. RI and the PI severity were not associated with oncological outcomes. The presence of PI abolished the survival benefit of adjuvant chemotherapy. Conclusions These results suggest that PI after curative CRC surgery is associated with impaired oncological outcomes. This survival disadvantage of PI was primarily derived from surgical site infection, not RI, and PI induced lower efficacy of adjuvant chemotherapy. Strategies to prevent PI and implement appropriate postoperative treatment may improve the quality of care and oncological outcomes in patients undergoing curative CRC surgery.

Abstract Aim This study aimed to predict cases of acute superior mesenteric artery (SMA) occlusion requiring bowel resection using occlusion site and time from symptom onset to diagnosis at five Japanese institutions. Advances in imaging, endovascular treatment, and perioperative management have improved the clinical outcomes of patients with acute SMA occlusion; however, in clinical practice it remains difficult to effectively determine patients requiring bowel resection. Methods We retrospectively analyzed the data of 48 patients (mean age: 82.5 y; male: 37.5%) diagnosed with acute SMA occlusion between June 2009 and August 2018. Background data of patients who required and did not require bowel resection were compared. A multivariable predictive model was developed using the time from symptom onset to diagnosis and whether SMA occlusion was proximal, including the origin of the middle colic artery. Results Fifteen patients (31.3%) died during the hospital stay. Atrial fibrillation (83.3%) was the most common comorbidity. The median time from symptom onset to diagnosis was 13.0 (interquartile range, 4.75–24.0) h. Laparotomy, bowel resection, and thrombus embolectomy were performed in 41 (85.4%), 26 (54.2%), and 21 (43.8%) patients, respectively. A logistic regression model achieved 78.6% sensitivity in predicting cases not requiring bowel resection. Proximal occlusion was significantly associated with the requirement for bowel resection (P = .039). Conclusion The time from symptom onset to diagnosis and occlusion site contributed to high sensitivity in determining the need for bowel resection in patients with acute SMA occlusion. Further prospective studies are warranted to investigate the clinical impact of this model.

Abstract Aim The National Health Insurance system has reimbursed robotic gastrointestinal surgery since April 2018 in Japan. Additionally, strict facility and surgeon standards were established by the government and the academic society. This study aimed to evaluate the prevalence and safety of robotic surgery using a Japanese nationwide web‐based database. Methods Patients who underwent the following robotic surgeries for malignant tumors in 2018 were included: esophagectomy (RE), total gastrectomy (RTG), distal gastrectomy (RDG), proximal gastrectomy (RPG), low anterior resection (RLAR), and rectal resections other than RLAR (RRR). The number of cases and surgical mortality rates each month were calculated to evaluate the prevalence and safety of robotic procedures. Results A total of 3281 patients underwent robotic gastrointestinal surgery. The monthly number of robotic surgeries nearly doubled in April 2018 when they were initially reimbursed by the National Health Insurance system. Operative mortality rates were 0.9%, 0.4%, 0.2%, and 2.8% for RE (n = 330), RTG (n = 239), RDG (n = 1167), and RPG (n = 109), respectively. No mortality was observed in RLAR (n = 1062) or RRR (n = 374). Conclusion Robotic surgery for gastrointestinal malignant tumors was safely introduced into daily clinical practice along with rigorous surgeon and facility standards in Japan.

Abstract Background The incidence of pancreatic neuroendocrine neoplasm (PNEN) has been increasing. Resection is typically indicated for PNEN, regardless of its size; however, the indications for its resection are controversial. This study aimed to evaluate the treatment results of surgical resection of PNEN at our institute. Methods In this single-center, retrospective, case-control study, 87 patients who underwent PNEN resection and 17 patients with PNEN who did not undergo surgical resection between 1993 and 2020 were included in this study. Clinical characteristics and outcomes were reviewed and statistically compared. Survival was also estimated for the patients in each cohort. Results Seventeen patients who underwent resection (20%) had lymph node metastasis. Tumors measuring ≥ 2.0 cm and multiple lesions were identified as independent predictors for lymph node metastasis (odds ratio [OR] 17.3, 95% confidence interval [CI] 3.0–100.0, p = 0.001 and OR 8.7, 95% CI 1.5–52.0, p = 0.018, respectively). There was a significant difference in the survival curves depending on the presence or absence of lymph node metastasis (5-year overall survival 74.7% vs. 94.3%, p < 0.001; 5-year recurrence-free survival: 66.3% vs. 93.6%, p < 0.001). All 17 PNEN cases under observation with a median 8 mm (range 5–23) tumor size for a median of 34 (range 2.4–114) months showed slight morphological change with a median tumor growth rate of 0.15 mm (range 0–3.33) per year. Conclusion Patients with tumors measuring ≥ 2.0 cm have a high probability of lymph node metastasis or recurrence, thereby requiring resection. PNEN measuring < 1.0 cm may be acceptable for observation.

Abstract Aim Using nationwide data collected over the past 20 years, we aimed to investigate deceased donor liver transplantation (DDLT) outcomes to develop a unique risk model that can be used to establish a standard for organ acceptance in Japan. Methods Data were collected for 449 recipients aged ≥18 years who underwent DDLT between 1999 and 2019. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to develop an original risk score model for 1‐year graft loss (termed the Japan Risk Index [JRI]). We developed risk indices according to recipient, donor, and surgery components (termed JRI‐R, D, and S, respectively). The JRI was validated via a 5‐fold cross‐validation. We also compared DDLT outcomes and risk indices among Era1 (−2011), Era2 (−2015), and Era3 (−2019). Results The 1‐year graft survival rate was 89.5% and improved significantly, reaching 84.7%, 87.6%, and 93.9% in Era1, Era2, and Era3, respectively. The JRI was calculated as JRI‐R (re‐transplantation, Model for End‐Stage Liver Disease score, medical condition in intensive care unit) × JRI‐D (age, catecholamine index, maximum sodium, maximum total bilirubin) × JRI‐S (total ischemic time) × 0.84. The risk model achieved a mean C‐statistic value of 0.81 in the validation analysis. The risk index was significantly lower in Era3 than in Era2. Conclusion Changes in the risk index over time indicated that avoiding risks contributed to the improved outcomes in Era3. The JRI is unique to adult DDLT in Japan and may be useful as a reference for organ acceptance in the future.

Abstract Background Organ/space surgical site infection (SSI) is a significant clinical problem. The postdiagnosis course of organ/space SSIs and the impact of its early diagnosis on clinical outcomes are yet to be clarified. Thus, we aimed to investigate the association between the timing of diagnosis and the clinical outcome of organ/space SSI. Methods This retrospective, single‐center cohort study evaluated patients who underwent elective gastrointestinal or hepatopancreatobiliary surgery between 2016 and 2020. Clinical outcomes were compared between the early group (ie, SSI diagnosed until postoperative day [POD] 4) and normal‐late group (ie, SSI diagnosed after POD 5). The primary outcome was the final C‐reactive protein (CRP) level within 14 d after organ/space SSI diagnosis. Results In total, 110 patients were evaluated. The median time of diagnosis was 7 d postoperatively (interquartile range, 5–9 d postoperatively). Compared with the normal‐late group, the early group included a higher proportion of patients with Clavien–Dindo grade ≥IIIb (8/21 vs 11/89, P = .01), higher final CRP value within 14 d after SSI diagnosis (mean, 4.49 mg/dL vs 2.27 mg/dL, P = .01), longer postoperative length of hospitalization (median, 45.0 d vs 33.0 d; P = .028), and worse 1‐y overall survival rate (74.8% vs 89.3%, P = .08). Conclusion Early diagnosed organ/space SSI are originally severe and may therefore be detected earlier. Importantly, early diagnosed organ/space SSI is likely to be severe and refractory.

Abstract Background Elective laparoscopic surgery is now widely accepted in the treatment of abdominal diseases because of its minimal invasiveness and rapid postoperative recovery. It is also used in the emergency setting for the diagnosis and treatment of acute diffuse peritonitis regardless of the causative disease. However, the value of laparoscopy in acute diffuse peritonitis remains unclear. In this study we aimed to show trends in the use of laparoscopy over time and compare the real‐world performance of laparoscopic surgery with that of open surgery for acute diffuse peritonitis due to gastrointestinal perforation. Methods We extracted data from the National Clinical Database, a nationwide surgery registration system in Japan, for patients with a diagnosis of acute diffuse peritonitis due to gastroduodenal or colorectal perforation between 2016 and 2019. Trends in the use of laparoscopy over time were identified. Patient characteristics, laboratory findings, surgical findings, and postoperative complications were compared between laparoscopic surgery and open surgery. Results Patients in poor condition and those with abnormal laboratory findings tended to undergo open surgery. Anesthesia time and operating time were longer for laparoscopic surgery in patients with gastroduodenal perforation but shorter in those with colorectal perforation. Fewer complications occurred in patients who underwent laparoscopic surgery. The number of institutions where laparoscopic surgery was performed and the proportion of the use of laparoscopy at each institution increased over time. Conclusion The use of laparoscopy is becoming common in surgery for acute diffuse peritonitis due to gastrointestinal perforation. This approach may be a useful option for acute diffuse peritonitis.

Abstract Background and Aim In Japan, the actual number of stoma constructions and stoma closures is not known. The aim of this study was to conduct a survey to determine the number of gastrointestinal stoma constructions and closures in Japan. Methods Enrolled participants comprised patients undergoing selected gastrointestinal surgeries who were recorded in the National Clinical Database. This database uses the “Common Items for Gastrointestinal Surgeons.” These procedures were formulated by the Japanese Society of Gastroenterological Surgery during 2013–2018. Results According to the National Clinical Database, a total of 154,323 gastrointestinal stomas were constructed between January 1, 2013 and December 31, 2018. By procedure, there were 78,723 cases of stoma construction, 39,653 of abdominoperineal resection, 2470 total pelvic exenteration procedures, and 33,572 Hartmann's procedures. The ratio of stoma closures to stoma constructions increased annually in patients under 70 y of age but not in older patients. Approximately 35% of total colectomies, 60% of proctocolectomies, and 20% of low anterior resections were accompanied by stoma construction. The number of patients with rectal cancer who underwent colostomy increased gradually during the study period and the number who underwent stoma construction increased among older patients. Conclusion The number of cases of gastrointestinal stoma construction has increased gradually in Japan, and the proportion of older patients is increasing each year. The purposes and surgical techniques for stoma construction are diverse and are expected to increase in Japan, a super‐aged society.

Abstract Aim Much attention has been paid to conversion therapy for stage IV gastric cancer, however, its operative comorbidities and survival benefit have not yet been clarified. CONVO‐GC‐1, an international retrospective cohort study, was designed to investigate the role of conversion surgery in Japan, Korea, and China. Methods The rate of operative complications was the primary endpoint and the overall survival (OS), according to the four‐category criteria previously published (Gastric Cancer:19; 2016), was analyzed as the secondary endpoint. Results A total of 1206 patients underwent surgery after chemotherapy with curative intent. Operative complications were observed in 290 (24.0%) patients in all grades, including pancreatic fistula and surgical site infection. The median survival time (MST) of all resected patients was 36.7 mo (M) and those of R0, R1, and R2 resection were 56.6 M, 25.8 M, and 21.7 M, respectively. Moreover, the MST of R0 patients were 47.8 M, 116.7 M, 44.8 M in categories 1, 2, and 3, respectively, and not reached in category 4. Interestingly, the MST of P1 patients was as favorable as that of P0CY1 patients if R0 resection was achieved. The MST of patients with liver metastasis was also favorable regardless of the number of lesions, and the MST of patients with para‐aortic lymph node (LN) No 16a1/b2 metastasis was not inferior to that of patients with para‐aortic LN No 16a2/b1 metastasis. Conclusion Conversion therapy for stage IV gastric cancer is safe and could be a new therapeutic strategy to improve the survival of patients, especially those with R0 resection.

Abstract Background Esophagectomy followed by gastric conduit reconstruction is a standard surgical procedure for esophageal cancer. However, there is no evidence of the superiority or inferiority of the posterior mediastinal (PM) versus the retrosternal (RS) reconstruction route with regard to short‐term outcomes after esophagectomy. We aimed to elucidate whether the reconstruction route can affect the short‐term outcomes after esophagectomy followed by gastric conduit reconstruction. Methods We reviewed the clinical data of patients who underwent esophagectomy between 2016 and 2018 from the Japanese National Clinical Database. This study included 9786 patients who underwent gastric conduit reconstruction through the PM or RS route with cervical anastomosis. Results Of the 9786 patients analyzed, 3478 and 6308 underwent gastric conduit reconstruction thorough the PM and RS routes, respectively. The incidence of anastomotic leak and surgical site infection (SSI) was significantly lower in the PM group than in the RS group (11.7% vs 13.8%, P = .005 and 8.4% vs 14.9%, P

Abstract Aim Preoperative inflammation‐based Glasgow prognostic score (GPS) is a useful tool for predicting long‐term prognosis in cancer patients. However, its association with postoperative short‐term outcomes remains unknown. The aim of this study is to investigate the association between GPS and postoperative morbidity and mortality among patients undergoing surgery for various gastrointestinal malignancies. Methods Using the Japanese National Clinical Database, we analyzed the records of 312 357 patients with gastrointestinal malignancy who underwent six typical elective surgeries, including esophagectomy, distal gastrectomy, total gastrectomy, right hemicolectomy, low anterior resection, and pancreaticoduodenectomy, between January 2015 and December 2018. We assigned GPS of 0, 1, or 2 to patients with no, one, or both decreased albumin and elevated C‐reactive protein levels, respectively. We investigated the relationship of GPS with operative morbidity and mortality for each procedure with adjustments for patients' demographics, preoperative status, comorbidities, and cancer stages. Results Crude operative morbidity was significantly higher for GPS 1 and 2 than GPS 0 patients in all procedures except pancreaticoduodenectomy. The postoperative length of hospital stay was significantly longer for GPS 1 and 2 patients in all procedures (P

Abstract Background We aimed to present the 2019 annual report of the gastroenterological section of the National Clinical Database (NCD). Methods We reviewed 609,589 cases recorded in 2019 and 5,029,764 cases registered from 2011 to 2019 for the 115 selected gastroenterological surgical procedures. Results The main features of gastroenterological surgery in Japan were similar to those described in the 2018 annual report, namely, that 1) operative numbers gradually increased in all procedures, except gastrectomy and hepatectomy, which decreased in these years; 2) in all eight major gastroenterological surgeries, the age distribution tended toward older patients; 3) the morbidity of esophagectomy, hepatectomy, and pancreaticoduodenectomy increased, but mortality was minimized in all procedures; 4) all eight major gastroenterological procedures have increasingly been performed under laparoscopy; and 5) board‐certified surgeons were increasingly involved. These trends in recent years were more prominent in 2019. Conclusions Thanks to the continuous cooperation and dedication of the surgeons, medical staff, and surgical clinical reviewers who registered the clinical data into the NCD, it is possible to understand the comprehensive landscape of surgery in Japan and to disclose new evidence in this field. The Japanese Society of Gastroenterological Surgery will continue to promote the value of this database and encourage the use of feedback and clinical studies using the NCD, now and in the future. Generating further approaches to surgical quality improvement are important directions for future research.

Abstract Background The effect of antithrombotic drugs on intraoperative operative blood loss volume in patients undergoing emergency surgery for generalized peritonitis is not well defined. The purpose of this study was to investigate the effect of antithrombotic drugs on intraoperative blood loss in patients with generalized peritonitis using a nationwide surgical registry in Japan. Method This retrospective cohort study used a nationwide surgical registry data from 2011 to 2017 in Japan. Propensity score matching for the use of antithrombotic drugs was used for the adjustment of age, gender, comorbidities, frailty, preoperative state, types of surgery, surgical approach, laboratory data, and others. The main outcome was intraoperative blood loss: comparison of intraoperative blood loss, ratio of intraoperative blood loss after adjusted for confounding factors, and variable importance of all covariates. Results A total of 70,105 of the eligible 75,666 patients were included in this study, and 2947 patients were taking antithrombotic drugs. Propensity score matching yielded 2864 well-balanced pairs. The blood loss volume was slightly higher in the antithrombotic drug group (100 [10–349] vs 70 [10–299] ml). After adjustment for confounding factors, the use of antithrombotic drugs was related to a 1.30-fold increase in intraoperative blood loss compared to non-use of antithrombotic drugs (95% CI, 1.16–1.45). The variable importance revealed that the effect of the use of antithrombotic drugs was minimal compared with surgical approach or type of surgery. Conclusion This study shows that while taking antithrombotic drugs is associated with a slight increase in intraoperative blood loss in patients undergoing emergency surgery for generalized peritonitis, the effect is likely of minimal clinical significance.

Abstract Aim We aimed to investigate whether later weekdays are related to worse short‐term outcomes after elective right hemicolectomy for colon cancer. Methods We retrospectively analyzed adult patients who underwent elective right hemicolectomy for colon cancer between 2012 and 2017. Records lacking details about surgical mortality were excluded, and multiple imputation was performed for other missing data (variables). The primary endpoint was surgical mortality, defined as the sum of 30‐day mortality and in‐hospital deaths within 90 days postoperatively. Using 22 clinical variables, hierarchal logistic regression modeling with clustering of patients from the same institutes was performed. Results Of the 112 658 patients undergoing elective right hemicolectomy for colon cancer, the 30‐day mortality and surgical mortality were 0.6% and 1.1%, respectively. Surgery on Friday was less frequent, accounting for 17.1% of all cases. The occurrence of severe postoperative complications, anastomotic leakage, or unadjusted odds ratio for surgical mortality did not show significant differences between weekdays. A hierarchal logistic regression model identified 19 independent factors for surgical mortality. Adjusted odds ratios for surgical mortality were 1.01 (95% confidence interval: 0.83‐1.22, P = .915), 0.86 (95% confidence interval: 0.71‐1.05, P = .144), 0.86 (95% confidence interval: 0.71‐1.05, P = .408), and 0.83 (95% confidence interval: 0.68‐1.03, P = .176) for Tuesday, Wednesday, Thursday, and Friday, respectively, showing no significant differences. Conclusion This study did not identify an evident difference in surgical mortality between weekdays; a safe elective right hemicolectomy for colon cancer is being offered throughout the week in Japan.

Abstract Aim We have previously reported the existence of lymph nodes surrounding the thoracic duct ( TDLN) and transthoracic esophagectomy (TTE) with thoracic duct (TD) resection increased the number of lymph nodes (LNs) retrieved. The current study aims to evaluate the prognostic impact of TDLN metastasis in esophageal cancer patients subdivided by its location and comparing the patients’ survival with those with extra‐regional LN metastasis. Methods Patients who underwent TTE with TD resection for esophageal squamous cell carcinoma (ESCC) were reviewed. Patients were classified into those with or without TDLN metastasis, and clinicopathological factors were compared between groups. TDLN was further divided into TDLN‐Ut/Mt/Lt based on the location in the mediastinum. The relapse‐free survival (RFS) and overall survival (OS) were compared between groups. Results Of 232 patients, TDLN metastasis was observed in 17 (7%). RFS and OS were significantly worse in the TDLN metastasis group. TDLN metastasis was shown to be an independent prognostic factor for RFS and OS in the multivariate analysis. The negative prognostic impact of TDLN metastasis was evident in TDLN‐Mt/Lt. The RFS and OS of patients with TDLN metastasis were almost identical to those with positive LN metastasis in extra‐regional LNs. Conclusion TDLN metastasis was proven to be a strong prognostic indicator. Although the TDLN has been included in the classification of regional LN in the current staging systems, it could be independently classified from the current regional LNs. Given that neoadjuvant therapy has been a standard, we might need to introduce adjuvant therapy when TDLN metastasis is observed.

Abstract Background and Aim In 2015, the Japanese Society of Gastroenterological Surgery (JSGS) initiated data verification in the gastroenterological section of the National Clinical Database (NCD) and reported high accuracy of data entry. Remote audits were introduced for data validation on a trial basis in 2016 and formally accepted into use in 2017‐2018. The aim of this study was to audit the data quality of the NCD gastroenterological section for 2016‐2018 and to confirm the high accuracy of data in remote audits. Methods Each year, 45‐46 hospitals were selected for audit. Twenty cases were randomly selected in each hospital, and the accuracy of patient demographic and surgical outcome data (46 items) was compared with the corresponding medical records obtained by visiting the hospital (site‐visit audit) or by mailing data from the hospital to the JSGS office (remote audit). Results A total of 136 hospitals were included, of which 88 (64.7%) had a remote audit, and 124 936 items were evaluated with an overall data accuracy of 98.1%. There was no significant difference in terms of data accuracy between site‐visit audit and remote audit. Accuracy, sensitivity, and specificity of mortality were 99.7%, 89.7%, 100% for site‐visit audits and 99.8%, 97.3%, 100% for remote audits, respectively. Mean time spent on data verification per case of remote audits was shorter than that of site‐visit audits (10.0 minutes vs 13.7 minutes, P

Abstract Background In Japan, the prevalence of synchronous multiple intramucosal gastric carcinoma is reported to be 5–15%. Here is a case of a synchronous small gastric carcinoma fulfilling the definite indication and curative criteria for endoscopic submucosal dissection with multiple lymph node metastases. Case presentation A Japanese woman in her fifties with a history of endoscopic resection for mucosal poorly differentiated adenocarcinoma was evaluated, with the UICC TNM classification stage being cT1aN0M0 cStageIA. She had undergone total gastrectomy with D1 + lymph node dissection. Histopathological examination revealed 16 individual sporadic lesions in the gastric body, with maximum diameter 3 mm and localization in the lamina propria. Twenty-seven nodes were resected, and metastasis of the carcinoma was revealed in 24 nodes. Conclusions Undifferentiated intramucosal gastric cancer has a relatively high probability of lymph node metastasis; however, synchronous early lesions are often overlooked. Frequent follow-up examinations may increase the detection of multiple gastric cancers.

Abstract Aim Appendicitis is divided into two categories: complicated appendicitis (CA) and uncomplicated appendicitis (UA). In pediatric patients with CA, the use of interval appendectomy (IA), which is non‐operative management followed by elective surgery, has decreased the number of postoperative complications. Before discussing the merit of IA for adult patients, we need to clarify whether the frequency and seriousness of the complication rate after emergency surgery is higher for CA than for UA. Methods This retrospective cohort study included adult patients who underwent appendectomy and who were registered in the National Clinical Database (NCD) from 2014 to 2016. Patients with CA who underwent emergency appendectomy comprised the CA group. Patients with UA comprised the UA group. Patients with chronic or recurrent appendicitis who underwent elective appendectomy comprised the elective appendectomy (EA) group. Primary outcomes were all morbidity, serious morbidity, and mortality within 30 days after appendectomy. Results We included 109 256 patients in the study: 14 798 CA, 86 876 UA, and 7582 EA patients. Compared with the UA group, the rates of all morbidity, serious morbidity, and mortality were significantly higher in the CA group. All morbidity, serious morbidity, and mortality rates were significantly lower in the EA group than in the other two groups. Conclusions We confirmed that emergency surgery for CA places the patient at relatively higher risk. We also showed that the risk associated with EA is significantly lower than that for the other methods.

Abstract Perioperative and surgical management of gastric cancer have been changing as pivotal phase II trials and landmark phase III trials offer new insights to the existing knowledge. The results of many landmark trials have been published or presented in the past year, many of which have changed or will change current clinical practice. For example, FLOT4 has completely changed the regimen of perioperative chemotherapy in Europe. Furthermore, evidence for minimally invasive surgery for clinical Stage I was firmly established by KLASS‐01 and JCOG0912 for distal gastrectomy and CLASS‐02, KLASS‐03, and JCOG1401 for total gastrectomy. Moreover, promising results were provided by CLASS‐01 and KLASS‐02 for locally advanced gastric cancer. For adjuvant chemotherapy, JACCRO GC‐07 (START‐2) has provided a new doublet regimen for pathological Stage III, which is often refractory to chemotherapy. Conversely, JCOG0501 poses a significant challenge for advanced tumors, such as large type 3 and scirrhous (type 4) tumors. In this review, we briefly review recent updates and discuss future perspectives of gastric cancer treatment.

Abstract Background Pheochromocytoma is a catecholamine-secreting tumour that leads to various symptoms. Haemoptysis is rarely caused by a pheochromocytoma occurring outside the bronchus or thoracic cavity. Here, we report the case of an extra-adrenal abdominal pheochromocytoma initially manifesting as haemoptysis/dyspnoea during exercise without classic symptoms. Case presentation A 22-year-old man with a history of severe dyspnoea experienced difficulties in breathing following a marathon owing to haemoptysis that required ventilator management 1 year before presentation. His father had undergone surgery for ectopic pheochromocytoma. Computed tomography (CT) revealed a 30-mm tumour between the inferior vena cava and pancreatic head while urinalysis revealed abnormally high noradrenaline levels. He was clinically diagnosed with an extra-adrenal abdominal ectopic pheochromocytoma. After controlling blood pressure, surgery was performed, and the tumour was successfully removed. Histopathology revealed chromogranin A (+), synaptophysin (+), S100 protein (+), and MIB-1 index of 1%. Therefore, the patient was finally diagnosed with extra-adrenal abdominal ectopic pheochromocytoma. Conclusions Haemoptysis is a rare manifestation of abdominal ectopic paraganglioma. Prompt consideration of pheochromocytoma/paraganglioma when patients experience haemoptysis without any other possible aetiology may prevent inappropriate diagnosis and treatment and ultimately fatalities.

Abstract Aim The advantages of laparoscopic right hemicolectomy over open surgery for colon cancer in general clinical practice are debated, as evidenced by the continued use of open surgery in a significant proportion of patients worldwide. This study aimed to assess and compare the clinical outcome of laparoscopic and open right hemicolectomy for colon cancer using data from the Japanese National Clinical Database. Methods A total of 72 299 patients who underwent laparoscopic (n = 46 084) and open (n = 26 215) right hemicolectomy for colon cancer between 2014 and 2018 were enrolled in this retrospective study. Short‐term outcome was compared between groups using propensity score matching analysis. Results The incidence of overall postoperative morbidity ≥ Clavien‐Dindo classification grade 3 was significantly higher in the open surgery group than the laparoscopic group (4.7% vs 3.2%, P