Comparison of the survival outcomes between retrocolic and antecolic Roux-en-Y reconstruction after gastrectomy for gastric cancer.

Background: There are two methods of Roux-en-Y (RY) reconstruction after gastrectomy: the antecolic route (ACR) and retrocolic route (RCR). There is no evidence to support that the ACR achieves comparable long-term survival. Methods: This was a multi-center historical cohort study. Patients diagnosed with clinical T3/4a and any N stage who underwent open gastrectomy and R0 resection for gastric adenocarcinoma between January 2006 and December 2012 were enrolled. The primary outcome was the hazard ratio of ACR for overall survival, with adjustment for confounding factors by propensity score matching, and a Cox proportional hazards model. Results: A total of 1758 eligible patients were identified from the database. After matching, 410 patients in the ACR and RCR groups were included in the final analysis. The adjusted hazard ratio (95% CI) for ACR was 1.148 (0.870-1.492). The five-year survival rates in the ACR and RCR groups were 74.3% (69.5-78.4) and 77.3% (72.3-81.2), respectively. The short-term surgical outcomes of the two groups did not differ to a statistically significant extent. Conclusion: The route used to lift the jejunum in RY reconstruction did not affect the incidence of long-term survival or postoperative complications. The ACR and RCR are both acceptable options for RY reconstruction during gastric cancer surgery.

Radiological Cutoff Values for Diagnosis of Lymph Node Metastasis in Colorectal Cancer With Multilevel Analysis.

Background/Aim: A cutoff value for lymph node diameter in colorectal cancer lymph node metastases has not been established. This prospective study aimed to investigate the direct association between swollen lymph nodes identified on preoperative computed tomography (CT) and pathological findings and proposed a cutoff value. Patients and Methods: We enrolled patients scheduled to undergo curative surgery with lymph node dissection for colorectal adenocarcinoma who underwent preoperative contrast-enhanced CT and had swollen lymph nodes ≥7 mm in diameter. Two gastrointestinal surgeons intraoperatively identified the target lymph nodes to assess the association between lymph node diameter and pathological findings. The diagnostic performance for lymph node metastasis was determined using multi-level logistic modelling. Results: A total of 109 patients were enrolled, and 225 swollen lymph nodes were pathologically evaluated. Using a cutoff value of ≥9 mm for the short diameter, the positive and negative predictive values, sensitivity, and specificity were 100.0% (99.6%-100.0%), 99.9% (99.1%-100.0%), 62.0% (45.6%-76.0%), and 84.9% (67.0%-94.0%), respectively. Conclusion: The cutoff value for improving the positive predictive value for the preoperative lymph node metastasis diagnosis in colorectal cancer patients should be at least 9 mm in diameter.

Preliminary Investigation of the Efficacy and Indications of Proton Beam Therapy for Stage IV Pancreatic Adenocarcinoma.

BACKGROUND: The present study aimed to evaluate proton beam therapy (PBT) for stage IV pancreatic adenocarcinoma and its metastases and define the criteria for eligibility. Materials and methods: We retrospectively evaluated the patients who had a histopathological diagnosis of pancreatic adenocarcinoma, had progressed to stage IV, and underwent PBT for both the primary and some metastatic lesions between 2017 and 2022. PBT was performed using the passive scattering technique. RESULTS: Sixteen patients (median age, 72 years; range, 55-85 years) were enrolled. All patients had stage IV pancreatic cancer at the initiation of PBT. The median duration from the date of stage IV diagnosis to the initiation of PBT was 5.8 (range, 0.4-13.5) months. Three patients had been diagnosed as having recurrent stage IV cancer at other institutions before their referral to our hospital because they had local recurrence and distant metastases after the resection of the primary tumor. Chemotherapy was as follows: pre-PBT, 0, 1, 2, and 3 lines in 4, 7, 4, and 1 patients, respectively; concurrent with PBT, 0 and 1 line in 11 and 5 patients, respectively; post-PBT, 0 and 1 line in 5 and 5 patients, respectively; and unknown, 6 patients. The median survival times (MSTs) from the date of stage IV diagnosis for the with or without non-irradiated active metastatic tumor were 11.4 and 20.1 months, respectively. Univariate analysis revealed that the performance status (PS) levels (p < 0.01), the carbohydrate antigen (CA) 19-9 tumor marker levels (p < 0.01), active tumors not treated with irradiation (p = 0.02), and with or without post-PBT chemotherapy (p < 0.01) were statistically significant factors. Multivariate analysis revealed that the CA 19-9 tumor marker levels (p= 0.04), the number of metastatic lesions (p = 0.049), and with or without non-irradiated active metastatic tumors (p = 0.02) were significant factors. CONCLUSION: PBT is indicated when the number of metastases is limited to ≤ 4 lesions and all tumors can be irradiated within the smallest possible number of irradiation fields that can be performed within the patient's tolerable time, which is a subjective duration that depends on the patient's reaction during each session. It may be a viable treatment option for patients with oligometastatic pancreatic cancer.

Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy.

BACKGROUND: The prognostic value of the pathological response to preoperative chemoradiotherapy (CRT) in rectal cancer (RC) remains unknown. OBJECTIVES: We aimed to assess the predictive value of the response to CRT that was derived from an evaluation of the histological findings (whole-section vs. representative-section sampling) and attempted to determine an objective cut-off value for the tumor regression grade (TRG). METHODS: We examined the association of the TRG with the outcomes (recurrence-free survival [RFS] and overall survival [OS]) of 78 patients with RC. Patients with RC treated with preoperative CRT were divided into development (30 cases) and validation (48 cases) cohorts. The TRG was classified as grades I (Ia, Ib), II, and III. The cut-off value was determined by receiver operating characteristic (ROC) curve analysis. RESULTS: The TRG determined from whole-section sampling versus representative-section sampling was more strongly correlated with patient survival. We found that in both cohorts, patients with a cut-off value of <73% had a poor prognosis. Finally, the cut-off value was found to be an independent predictive factor in both univariate and multivariate analysis. CONCLUSIONS: The TRG that was used to evaluate patients with RC who underwent preoperative CRT was an independent prognostic factor for outcome.

Strangulated Bowel Obstruction Due to Hiatal Hernia After Laparoscopic Total Gastrectomy.

Laparoscopic total gastrectomy results in more internal hernias than open surgery. However, there are few reports of incarcerated hiatal hernia after laparoscopic total gastrectomy. Here, we report a case of a 79-year-old male who underwent urgent surgical intervention for a strangulated intestinal obstruction due to an incarcerated hernia through the esophageal hiatus following laparoscopic total gastrectomy. In this case, an esophageal hiatal hernia was present before gastrectomy, but was not repaired. Additionally, the patient experienced significant weight loss after gastrectomy. Preoperative hiatal hernia and marked postoperative weight loss may pose risks.

A rare case of neuroendocrine cell tumor mixed with a mucinous component in the ampulla of Vater.

BACKGROUND: A rare case of neuroendocrine cell tumor (NET) having both conventional and mucinous components was reported. Mucinous NET is rarely encountered in the pathological diagnosis of gastrointestinal (GI) tumors. Here we examined the mechanism for transformation of conventional NETs into mucinous NETs. CASE PRESENTATION: Macroscopic examination revealed a tumor with ulceration in the ampulla of Vater that measured 1.7 cm in its largest diameter. Histologically, the tumor comprised two components: a tubular/ribbon-like feature and small nests floating in a mucinous lake. The tumor nests showed sheet, nest and ribbon-like structures of small cells having eosinophilic cytoplasm as well as small-sized nuclei with dense hyperchromatin. Immunohistochemical analysis showed tumor cells positive for pan-endocrine markers (synaptophysin, CD56, INSM1 and chromogranin). Based on the histological findings, the solid and mucinous components were diagnosed as conventional and mucinous NETs, respectively. Grading was NET G2 based on 12.8% and 13.2% Ki-67-positive cells in the solid and mucinous components, respectively. Immunohistochemically, the mucin phenotype of this tumor was gastric and intestinal. Only the mucinous NET component had cytoplasmic CD10 expression. Examination using a customized gene panel detected only a DPC4 mutation, which was limited to the mucinous component. CONCLUSIONS: Coexistence of conventional and mucinous NETs could provide important insight into evaluating the NET subtype histogenesis. Moreover, molecular alterations including cytoplasmic expression of CD10 and the DPC4 mutation can contribute to interpretation of tumor pathogenesis.

Proton beam reirradiation for locally recurrent rectal cancer patients with prior pelvic irradiation.

The aim of the present study was to report the feasibility of proton beam reirradiation for patients with locally recurrent rectal cancer (LRRC) with prior pelvic irradiation. The study population included patients who were treated with proton beam therapy (PBT) for LRRC between 2008 and December 2019 in our institution. Those who had a history of distant metastases of LRRC, with or without treatment, before reirradiation, were excluded. Overall survival (OS), progression-free survival (PFS) and local control (LC) were estimated using the Kaplan-Meier method. Ten patients were included in the present study. The median follow-up period was 28.7 months, and the median total dose of prior radiotherapy (RT) was 50 Gy (range, 30 Gy-74.8 Gy). The median time from prior RT to reirradiation was 31.5 months (range, 8.1-96.6 months), and the median reirradiation dose was 72 Gy (relative biological effectiveness) (range, 56-77 Gy). The 1-year/2-year OS, PFS and LC rates were 100%/60.0%, 20.0%/10.0% and 70.0%/58.3%, respectively, with a median survival time of 26.0 months. Seven patients developed a Grade 1 acute radiation dermatitis, and no Grade ≥ 2 acute toxicity was recorded. Grade ≥ 3 late toxicity was recorded in only one patient, who had developed a colostomy due to radiation-related intestinal bleeding. Reirradiation using PBT for LRRC patients who had previously undergone pelvic irradiation was feasible. However, the indications for PBT reirradiation for LRRC patients need to be considered carefully due to the risk of severe late GI toxicity.

The pattern-based interpretation of p53 immunohistochemical expression as a surrogate marker for TP53 mutations in colorectal cancer.

Mutations in the TP53 gene, most commonly observed in colorectal cancer (CRC), play an essential role in colorectal carcinogenesis. Although p53 immunohistochemical (IHC) expression patterns have been argued to serve as an excellent surrogate marker for TP53 mutations, its performance has not been confirmed in CRC. We aimed to determine whether p53 IHC expression patterns accurately predict TP53 mutation status as examined by next-generation sequencing (NGS). We performed p53 IHC and sequencing of TP53 by NGS in 92 CRC cases with a microsatellite stable phenotype to investigate the correlation between TP53 mutation status and p53 IHC expression. The concordance between p53 IHC and TP53 mutation was 84/92 (91.3%) overall. However, 6 mutant cases were found in 39 cases with a wild-type IHC pattern. Additionally, there were two discordant cases in which an abnormal p53 IHC pattern (overexpression or cytoplasmic pattern) was found, while NGS detected wild-type p53. Therefore, the optimized p53 IHC performs well and serves as a surrogate test for TP53 mutation in CRC cases. Furthermore, it demonstrates excellent reproducibility between two independent experienced pathologists and may have novel clinical utility for molecular classification algorithms in CRC. We suggest that the four-tier classification of p53 IHC patterns is helpful to evaluate molecular colorectal carcinogenesis.

Impact of treatment guidelines and pivotal clinical trial results on a surgeon's decision regarding treatment for gastric cancer: a retrospective cohort study using the National Clinical Database.

PURPOSES: The present study evaluated the impact of clinical guidelines for gastric cancer surgery on surgeons' choice of procedure in real-world practice. We focused on the 2014 guideline revision recommending laparoscopic surgery and the evidence concerning splenectomy for prophylactic lymphadenectomy reported in 2015 using the National Clinical Database, which is the most comprehensive database in Japan. METHODS: We investigated the monthly percentages of laparoscopic distal gastrectomies performed for stage I gastric cancer (LDG%) and splenectomies performed during total gastrectomy for advanced cancer (TGS%) between 2014 and 2017. We evaluated the descriptive statistics of the time-series changes in the LDG%, TGS%, and annual trends of outcomes. RESULTS: In total, 124,787 patients were enrolled. The mean LDG% and TGS% were 69.8% and 9.2%, respectively. The LDG% and TGS% were 66.4% and 16.7%, respectively, in January 2014 and 73.1% and 5.9%, respectively, in December 2017. LDG% consistently increased, and TGS% showed a consistent downward trend throughout the observation period. There was no significant change in this trend after the publication of the guideline recommendations or clinical trial results. CONCLUSION: No significant changes in surgical procedures were observed after publication of the guidelines or results of clinical trials.

Histopathological vertical margin positivity in cold snare polypectomy and mucosal resection for sessile serrated lesions.

BACKGROUND AND AIMS: Evidence regarding the status of the vertical margin of sessile serrated lesions (SSLs) resected using cold snare polypectomy (CSP) is lacking, and whether a histopathologically positive vertical margin is related to recurrence remains unclear. Therefore, this preliminary study aimed to clarify the rates of positive or unevaluable vertical and horizontal margins and the rate of muscularis mucosae resection in SSLs treated using CSP compared with those treated with endoscopic mucosal resection (EMR). METHODS: Histological outcomes of patients treated with CSP or EMR for SSL were evaluated in this single-center observational study. The primary outcome was the incidence of histopathologically positive vertical margins in CSP and EMR. Furthermore, the comparisons were adjusted for confounding factors using propensity score matching. RESULTS: Overall, 82 patients with SSLs were included in the CSP and EMR groups after matching. The incidence of positive histological vertical margins in the CSP and EMR groups were 67.1% and 2.4%, respectively (p<0.001). Regarding the evaluation of the presence of muscularis mucosae, 29.3% and 98.8% of the patients in the CSP and EMR groups, respectively, had a complete muscularis mucosae resection (p<0.001). CONCLUSIONS: A rigorous histopathologic evaluation revealed that for SSLs, CSP more frequently leads to positive vertical margins than EMR.

Prognostic impact and survival outcomes of colon perforation in patients with metastatic colorectal cancer: a multicenter retrospective cohort study.

BACKGROUND: Colon perforation caused by colorectal cancer (CRC) is a fatal condition requiring emergency intervention. For patients with metastatic lesions, surgeons face difficult decisions regarding whether to resect the primary and metastatic lesions. Moreover, there is currently no established treatment strategy for these patients. This study aimed to investigate the clinical practice and long-term outcomes of patients with metastatic CRC diagnosed with the onset of colon perforation. METHODS: We performed a population-based multicenter cohort study. Consecutive patients diagnosed with stage IV CRC between 2008 and 2015 at all designated cancer hospitals in Fukushima Prefecture, Japan, were enrolled in this study. We evaluated the impact of colon perforation on the survival outcomes of patients with metastatic CRC. The main outcome was the adjusted hazard ratio (aHR) of perforation for overall survival (OS). Survival time and HRs were estimated using Kaplan‒Meier and Cox proportional regression analyses. RESULTS: A total of 1258 patients were enrolled (perforation: n = 46; non-perforation: n = 1212). All but one of the patients with perforation underwent primary resection or colostomy and 25 cases were able to receive chemotherapy. The median OS for the perforation and non-perforation groups was 19.0 and 20.0 months, respectively (p = 0.96). Moreover, perforation was not an independent prognostic factor (aHR: 0.99; 95% confidence interval: 0.61-1.28). CONCLUSIONS: In metastatic CRC, perforation is not necessarily a poor prognostic factor. Patients with perforation who undergo primary tumor resection or colostomy and prompt initiation of systemic chemotherapy might be expected to have a survival time similar to that of patients with non-perforated colon.

Exploration of acoustical features reflecting bowel motion using simultaneous measurements of X-ray fluoroscopy and bowel sounds.

In clinical practice, bowel sounds are often used to assess bowel motility. However, the mechanism of bowel-sound occurrence is unknown. Furthermore, there is no objective evidence indicating a relationship between bowel motility and bowel sounds, and diagnoses have been based on empirically established criteria. In this study, simultaneous X-ray fluoroscopy and bowel-sound measurements were used to reveal the mechanism of bowel-sound occurrence. The results indicate that the flow of luminal contents may cause bowel sounds. Additionally, on the basis of the hypothesis that bowel motility recovers with the postoperative course, bowel-sound features that reflect bowel motion were explored, revealing that the current diagnosis indices are appropriate.

Early administration of postoperative BCAA-enriched PPN may improve lean body mass loss in gastric cancer patients undergoing gastrectomy.

BACKGROUND: It has been reported that weight loss or lean body mass (LBM) loss after gastrectomy for gastric cancer is associated with prognosis and nutritional support alone is insufficient to prevent LBM loss. Branched-chain amino acids (BCAA) play an important role in muscle catabolism, however their clinical effects on suppression of LBM loss in gastric cancer patients undergoing gastrectomy remains elusive. In this current study, we investigated the effect of our original PPN regimen including BCAA (designated to BCAA-regimen) on LBM loss. METHODS: We conducted a randomized controlled trial (RCT) at a single institution where patients undergoing gastrectomy were assigned to either receive a five-day early postoperative course of the BCAA-regimen (BCAA group) or conventional nutrition. The primary endpoint was the % reduction in LBM at postoperative day 7. The secondary endpoints included the % reduction in LBM at 1 and 3 months postsurgery. RESULTS: At postoperative day 7, LBM loss in the BCAA group tended to be lower than in the control group (0.16% vs. 1.7%, respectively; P = 0.21), while at 1 month postsurgery, LBM loss in the BCAA group was significantly different to that of the control group (- 0.3% vs. 4.5%, respectively; P = 0.04). At 3 months postgastrectomy, however, LBM loss was similar between the BCAA and the control groups. CONCLUSION: Our RCT clinical trial clarified that early administration of the postoperative BCAA regimen improved LBM loss at 1 month after surgery in gastric cancer patients undergoing gastrectomy.

Feasibility and Safety of Adjuvant Chemotherapy for Resected Colorectal Cancer in Patients With Renal Insufficiency: A Pooled Analysis of Individual Patient Data from Five Japanese Large-scale Clinical Trials.

BACKGROUND/AIM: The incidence of chemotherapy-related adverse events in colorectal cancer patients with renal insufficiency has been compared to patients with normal renal function in only a few studies. The purpose of this analysis was to verify the feasibility and safety of adjuvant chemotherapy for postoperative colorectal cancer patients with renal insufficiency. PATIENTS AND METHODS: Adverse events and discontinuation of adjuvant chemotherapy for patients with curatively resected locally advanced colorectal cancer were examined using a combined database of individual patient data obtained from five large-scale clinical trials (n=4,106). The renal function of patients was classified into Level (L) 1-2: ≥60 ml/min and L3-4: <60 ml/min. RESULTS: As Grade 3 adverse events, hematological toxicities, such as neutropenia and anemia, and gastrointestinal disorders, such as diarrhea and vomiting, were significantly more frequent in the L3-4 group. Moreover, the time-to-treatment discontinuation in the L3-4 group was higher (hazard ratio=1.21, p=0.0012). T factor, N factor, and creatinine clearance level were found to be independent risk factors for the discontinuation of adjuvant chemotherapy. In the subgroup analysis of FOLFOX, neutropenia and diarrhea were significantly common in the L3-4 group, but neurotoxicities were not different. There was no significant difference in the discontinuation of adjuvant FOLFOX. CONCLUSION: Adverse events of adjuvant chemotherapy in patients with resected colorectal cancer were associated with renal insufficiencies. Since adverse events have the potential to shorten the duration of treatment, especially when using chemotherapy without oxaliplatin, careful management, including dose reduction, may be important in patients with renal insufficiency.

Clinical Indicators to Determine the Timing of Surgery for Adhesive Small Bowel Obstruction.

BACKGROUND: Decompression of the intestine with a long tube or nasogastric tube is the first-choice treatment for adhesive small bowel obstruction (ASBO). Scheduling surgery while weighing the risks of surgery against conservative care is a crucial factor in clinical decision-making. Whenever feasible, unnecessary surgeries should be avoided, and it is essential to provide clinical markers for this. This study aimed to obtain evidence regarding the optimal timing of ASBO and when conservative treatment options are not successful. METHODS: The data of patients diagnosed with ASBO and receiving long tube insertion for more than 7 days were reviewed. We investigated transit ileal drainage volume and recurrence. The primary outcomes were the change in the drainage volume from the long tube over time and the percentage of patients who required surgery. We evaluated some cutoff values to determine the indication for surgery based on the insertion duration and volume of long tube drainage. RESULTS: Ninety-nine patients were enrolled in this study. Fifty-one patients showed improvement with conservative treatment, whereas 48 ultimately required surgery. When a daily drainage volume of ≥500 mL was considered an indication for surgery, 13-37 cases (25%-72%) would be judged unnecessary within 6 days of long tube insertion, while 5 cases (9.8%) would be judged unnecessary on day 7. DISCUSSION: Unnecessary surgical interventions for ASBO might be avoided by assessing the drainage volume on day 7 after inserting a long tube.

The clinical impacts of postoperative complications after colon cancer surgery for the clinical course of adjuvant treatment and survival.

AIM: We investigated whether or not postoperative complications (POCs) themselves have a negative survival impact or indirectly worsen the survival due to insufficient adjuvant chemotherapy in a pooled analysis of two large phase III studies performed in Japan PATIENTS AND METHODS: The study examined the patients who enrolled in 1304, phase III study comparing the efficacy of 6 and 12 months of capecitabine as adjuvant chemotherapy for stage III colon cancer patients and in 882, a phase III study to confirm the tolerability of oxaliplatin, fluorouracil, and l-leucovorin in Japanese stage II/III colon cancer patients. In our study, POCs were defined as the following major surgical complications: anastomotic leakage, pneumonia, bowel obstruction/ileus, surgical site infection, postoperative bleeding, urinary tract infection, and fistula. Patients were classified as those with POCs (C group) and those without POCs (NC group). RESULTS: A total of 2095 patients were examined in the present study. POCs were observed in 169 patients (8.1%). The overall survival (OS) rates at 5 years after surgery were 75.3% in the C group and 86.5% in the NC group (p = 0.0017). The hazard ratio of POCs for the OS in multivariate analysis was 1.70 (95% confidence interval, 1.19 to 2.45; p = 0.0040). The time to adjuvant treatment failure (TTF) of adjuvant chemotherapy was similar between the groups, being 68.6% in the C group and 67.1% in the NC group for the 6-month continuation rate of adjuvant chemotherapy. The dose reduction rate of adjuvant chemotherapy and adjuvant treatment suspension rate were also similar between the groups (C vs. NC groups: 45.0% vs. 48.7%, p = 0.3520; and 52.7% vs. 55.0%, p = 0.5522, respectively). CONCLUSION: POCs were associated with a poor prognosis but did not affect the intensity of adjuvant chemotherapy. These results suggested that POCs themselves negatively influence the survival.

Delayed Perforation of Colorectal Endoscopic Submucosal Dissection Treated by Endoscopic Ultrasound-Guided Drainage.

We report a case of a 70-year-old male with delayed perforation in the cecum treated by endoscopic ultrasonography-guided drainage for a pelvic abscess. The lesion was a 50-mm laterally spreading tumor, and endoscopic submucosal dissection (ESD) was performed. No perforation was detected during the operation, and en bloc resection was achieved. He had fever and abdominal pain on postoperative day (POD) 2. Computed tomography (CT) revealed the intra-abdominal free air, leading to a diagnosis of delayed perforation after ESD. Vital signs were stable, the perforation was considered minor, and endoscopic closure was attempted. The colonoscopy under fluoroscopy showed no perforation in the ulcer and no leakage of the contrast medium. He was managed conservatively with antibiotics and nothing per os. Symptoms improved; however, a follow-up CT on POD 13 revealed a 65-mm pelvic abscess, and endoscopic ultrasound (EUS)-guided drainage was successfully performed. The follow-up CT on POD 23 showed the reduction of abscess, and the drainage tubes were removed. Emergent surgical treatment is crucial in delayed perforation because it has a poor prognosis, and reports of conservative therapy for colonic ESD with delayed perforation are few. The present case was managed with antibiotics and EUS-guided drainage. Thus, EUS-guided drainage can be a treatment option for delayed perforation after colorectal ESD, if the abscess is localized.

Impact of guideline recommendation for novel surgical procedures on surgeons' decisions: a time series analysis of gastric cancer surgeries from a nationwide cohort study.

BACKGROUND: Since two Japanese guidelines, for gastric cancer treatment and for minimally invasive surgery, were simultaneously revised in 2014, laparoscopic distal gastrectomy has been a standard procedure for clinical stage I gastric cancer. MATERIALS AND METHODS: We evaluated the impact of this revision on surgeons' decision-making using a nationwide inpatient database in Japan. We described the time trends in the proportion of laparoscopic surgery from January 2011 to December 2018. We performed an interrupted time series analysis; the exposure time point was August 2014, and the main outcome was the change in slope before and after the revision of the guidelines. We performed a subgroup analysis of hospital volume and the odds ratio (OR) for postoperative complications according to exposure. RESULTS: A total of 64 910 patients who underwent subtotal gastrectomy for stage I disease were identified. During the study period, the proportion of laparoscopic surgery showed a consistent increase from 47.4 to 81.2%. After the revision, the slope of the increase was rather slow; the OR [95% CI] was 0.601 [0.548-0.654] before the revision and 0.219 [0.176-0.260] after the revision. The adjusted ORs were 0.642 [0.575-0.709] before the revision and 0.240 [0.187-0.294] after the revision. CONCLUSION: The revision of the guidelines recommending laparoscopic surgery had little impact on surgeons' decisions regarding the choice of procedure.