Adjuvant nivolumab plus chemotherapy versus placebo plus chemotherapy for stage III gastric or gastro-oesophageal junction cancer after gastrectomy with D2 or more extensive lymph-node dissection (ATTRACTION-5): a randomised, multicentre, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: In Asia, adjuvant chemotherapy after gastrectomy with D2 or more extensive lymph-node dissection is standard treatment for people with pathological stage III gastric or gastro-oesophageal junction (GEJ) cancer. We aimed to assess the efficacy and safety of adjuvant nivolumab plus chemotherapy versus placebo plus chemotherapy administered in this setting. METHODS: ATTRACTION-5 was a randomised, multicentre, double-blind, placebo-controlled, phase 3 trial conducted at 96 hospitals in Japan, South Korea, Taiwan, and China. Eligible patients were aged between 20 years and 80 years with histologically confirmed pathological stage IIIA-C gastric or GEJ adenocarcinoma after gastrectomy with D2 or more extensive lymph-node dissection, with an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 and available tumour tissue for PD-L1 expression analysis. Patients were randomly assigned (1:1) to receive either nivolumab plus chemotherapy or placebo plus chemotherapy via an interactive web-response system with block sizes of four. Investigational treatment, either nivolumab 360 mg or placebo, was administered intravenously for 30 min once every 3 weeks. Adjuvant chemotherapy was administered as either tegafur-gimeracil-oteracil (S-1) at an initial dose of 40 mg/m2 per dose orally twice per day for 28 consecutive days, followed by 14 days off per cycle, or capecitabine plus oxaliplatin consisting of an initial dose of intravenous oxaliplatin 130 mg/m2 for 2 h every 21 days and capecitabine 1000 mg/m2 per dose orally twice per day for 14 consecutive days, followed by 7 days off treatment. The primary endpoint was relapse-free survival by central assessment. The intention-to-treat population, consisting of all randomly assigned patients, was used for analysis of efficacy endpoints. The safety population, defined as patients who received at least one dose of trial drug, was used for analysis of safety endpoints. This trial is registered with ClinicalTrials.gov (NCT03006705) and is closed. FINDINGS: Between Feb 1, 2017, and Aug 15, 2019, 755 patients were randomly assigned to receive either adjuvant nivolumab plus chemotherapy (n=377) or adjuvant placebo plus chemotherapy (n=378). 267 (71%) of 377 patients in the nivolumab group and 263 (70%) of 378 patients in the placebo group were male; 110 (29%) of 377 patients in the nivolumab group and 115 (31%) of 378 patients in the placebo group were female. 745 patients received assigned treatment (371 in the nivolumab plus chemotherapy group; 374 in the placebo plus chemotherapy group), which was the safety population. Median time from first dose to data cutoff was 49·1 months (IQR 43·1-56·7). 3-year relapse-free survival was 68·4% (95% CI 63·0-73·2) in the nivolumab plus chemotherapy group and 65·3% (59·9-70·2) in the placebo plus chemotherapy group; the hazard ratio for relapse-free survival was 0·90 (95·72% CI 0·69-1·18; p=0·44). Treatment-related adverse events occurred in 366 (99%) of 371 patients in the nivolumab plus chemotherapy group and 364 (98%) of 374 patients in the placebo plus chemotherapy group. Discontinuation due to adverse events was more frequent in the nivolumab plus chemotherapy group (34 [9%] of 371 patients) than the placebo plus chemotherapy group (13 [4%] of 374 patients). The most common treatment-related adverse events were decreased appetite, nausea, diarrhoea, neutrophil count decreased, and peripheral sensory neuropathy. INTERPRETATION: The results of this trial do not support the addition of nivolumab to postoperative adjuvant therapy for patients with untreated, locally advanced, resectable gastric or GEJ cancer. FUNDING: Ono Pharmaceutical and Bristol Myers Squibb.

Molecular features and prognostic factors of locally advanced microsatellite instability-high gastric cancer.

BACKGROUND: Microsatellite instability-high (MSI-H) tumors are distinct molecular subtypes in gastric cancer. However, a few studies have comprehensively reported the molecular features of MSI-H tumors and their prognostic factors in locally advanced gastric cancer. This study aimed to clarify the molecular features and prognostic factors of locally advanced MSI-H gastric cancer. METHODS: This study included 499 patients with locally advanced gastric cancer who underwent radical gastrectomy. We evaluated the MSI status and compared with previously published whole-exome sequencing, panel sequencing, and gene expression profiling data. Clinicopathological characteristics and molecular profiles were compared between patients with MSI-H and microsatellite stable (MSS) gastric cancer. A subgroup analysis of survival was performed in patients with MSI-H gastric cancer. RESULTS: MSI-H tumors were detected in 79 of 499 patients (15.8%). MSI-H tumors were associated with an increased tumor mutational burden, MLH1 downregulation, CD274 (PD-L1) upregulation, and enrichment of cell cycle pathways. Among patients with MSI-H gastric cancer, the disease-specific survival (DSS) tended to be better in the surgery plus tegafur, gimeracil, and oteracil potassium (S-1) adjuvant chemotherapy group than in the surgery alone group, especially for stage III patients. Furthermore, DSS was better in the T cell-inflamed gene expression signature-high group, and it tended to be worse in the non-solid type poorly differentiated adenocarcinoma group. CONCLUSIONS: The molecular features and prognostic factors of locally advanced MSI-H gastric cancer were clarified. S-1 adjuvant chemotherapy appears to be beneficial, and the T cell-inflamed gene expression signature and histopathological type are prognostic factors in MSI-H tumors.

Prognostic Impact of Post-operative Infectious Complications in Gastric Cancer Patients Receiving Neoadjuvant Chemotherapy: Post Hoc Analysis of a Randomized Controlled Trial, JCOG0501.

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

Postoperative sarcopenia increases both gastric cancer and other-cause mortality in older adults undergoing radical gastrectomy for cancer.

BACKGROUND & AIMS: Preoperative sarcopenia in gastric cancer is associated with increased postoperative complications and reduced long-term survival. However, the association between postoperative sarcopenia and long-term outcomes remains unclear. Therefore, this study aims to clarify the association between sarcopenia after gastrectomy for gastric cancer and survival outcomes. METHODS: This retrospective study included 1512 patients aged ≥65 who underwent curative gastric resection for clinical stage I-III primary gastric cancer during 2008-2018. Sarcopenia was assessed preoperatively by measuring arm muscle area and grip strength, which was repeated 1 month after surgery. We compared the clinical characteristics, surgical treatments, and long-term outcomes between the postoperative normal and sarcopenia groups. RESULTS: Sarcopenia was observed in 173 and 305 patients pre- and postoperatively, respectively. Factors increasing the risk of postoperative sarcopenia included age of ≥75, lower preoperative body mass index, diabetes, and clinical stage II/III gastric cancer. Patients with postoperative sarcopenia after surgery had a significantly lower overall survival rate (hazard ratio [HR] 2.596, p < 0.001). Furthermore, postoperative sarcopenia was linked to decreased overall survival in patients with (HR 2.813, p = 0.002) and without (HR 1.925, p < 0.001) preoperative sarcopenia. Cumulative incidence showed significantly higher rates of deaths due to gastric cancer (HR 1.928, p < 0.001) and other causes (HR 2.736, p < 0.001) in the postoperative sarcopenia group. CONCLUSIONS: Postoperative sarcopenia in gastric cancer is linked to an increased risk of death due to cancer and other causes, underscoring the importance of perioperative sarcopenia management strategies.

Clinical impact of skeletal muscle mass change during the neoadjuvant chemotherapy period in patients with gastric cancer: An ancillary study of JCOG1002.

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

Gastric inflammatory myofibroblastic tumor: a case report.

BACKGROUND: Inflammatory myofibroblastic tumor (IMT) of the stomach is an uncommon mesenchymal neoplasm. We present a case of gastric submucosal tumor (SMT) where the final diagnosis was IMT. CASE PRESENTATION: A 69-year-old man presented with a 24-mm SMT on the posterior wall of the middle third of the stomach that was detected by screening upper gastrointestinal endoscopy. Abdominal contrast-enhanced computed tomography showed that the tumor was well-enhanced. Although endoscopic ultrasonography-guided biopsy was performed, the histological diagnosis was not confirmed preoperatively. Since the tumor was clinically suspected to be a gastrointestinal stromal tumor, we performed gastric wedge resection by laparoscopic-endoscopic cooperative surgery. Pathologically, proliferative spindle cells with a positive reaction for smooth muscle actin, negativity for c-kit, desmin, s-100, CD34, STAT-6, ß-catenin and anaplastic lymphoma kinase 1 were identified. Hence, the tumor was finally diagnosed as an IMT originating from the stomach. CONCLUSIONS: When an SMT of the stomach is identified, the possibility of gastric IMT should be considered.

Risk factors for abdominal surgical infectious complications after distal gastrectomy for gastric cancer: A post-hoc analysis of a randomized controlled trial (JCOG0912).

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

Short-term outcomes of preoperative chemotherapy with docetaxel, oxaliplatin, and S-1 for gastric cancer with extensive lymph node metastasis (JCOG1704).

BACKGROUND: The prognosis for marginally resectable gastric cancer with extensive lymph node metastasis (ELM) remains unfavorable, even after R0 resection. To assess the safety and efficacy of preoperative docetaxel, oxaliplatin, and S-1 (DOS), we conducted a multicenter phase II trial. METHODS: Eligibility criteria included histologically proven HER2-negative gastric adenocarcinoma with bulky nodal (bulky N) involvement around major branched arteries or para-aortic node (PAN) metastases. Patients received three cycles of docetaxel (40 mg/m2, day 1), oxaliplatin (100 mg/m2, day 1), and S-1 (80-120 mg/body, days 1-14), followed by gastrectomy with D2 plus PAN dissection. Subsequently, patients underwent postoperative chemotherapy with S-1 for 1 year. The primary endpoint was major (grade ≥ 2a) pathological response rate (pRR) according to the Japanese Classification of Gastric Carcinoma criteria. RESULTS: Between October 2018 and March 2022, 47 patients (bulky N, 20; PAN, 17; both, 10) were enrolled in the trial. One patient was ineligible. Another declined any protocol treatments before initiation. Among the 45 eligible patients who initiated DOS chemotherapy, 44 (98%) completed 3 cycles and 42 (93%) underwent R0 resection. Major pRR and pathological complete response rates among the 46 eligible patients, including the patient who declined treatment, were 57% (26/46) and 24% (11/46), respectively. Common grade 3 or 4 toxicities were neutropenia (24%), anorexia (16%), febrile neutropenia (9%), and diarrhea (9%). No treatment-related deaths occurred. CONCLUSIONS: Preoperative chemotherapy with DOS yielded favorable pathological responses with an acceptable toxicity profile. This multimodal approach is highly promising for treating gastric cancer with ELM.

Early endpoints of a randomized phase II trial of preoperative chemotherapy with S-1/CDDP with or without trastuzumab followed by surgery for HER2-positive resectable gastric or esophagogastric junction adenocarcinoma with extensive lymph node metastasis: Japan Clinical Oncology Group study JCOG1301C (Trigger Study).

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

Association between the antiadhesion membrane and small bowel obstruction after open gastrectomy: A supplemental analysis of the randomized controlled JCOG1001 trial.

Aim: Postoperative small bowel obstruction (SBO) is one of the major complications that is mainly caused by postoperative adhesion. Recently, the antiadhesion membrane has become popular for postoperative SBO prevention. However, its efficacy is yet to be confirmed in the gastric cancer surgery field. Here, we conducted the supplemental analysis of the randomized controlled trial JCOG1001 to investigate the efficacy of the antiadhesion membrane on SBO prevention in patients with open gastrectomy for gastric cancer. Methods: Of the 1204 patients enrolled in JCOG1001, 1200 patients were included. The development of SBO of Grade ≥ IIIa according to the Clavien-Dindo classification was recorded. Univariable and multivariable analyses were performed using the Fine and Gray model to determine the risk factors for SBO. Results: Fifty-one patients developed SBO (median follow-up duration: 5.6 years). Total gastrectomy, combined resection, and blood loss significantly increased the risk for SBO development in the univariable analysis. Large amount of blood loss was independently associated with SBO development in the multivariable analysis (hazard ratio [HR], 3.089; 95% confidence interval [CI], 1.562-6.109, p = 0.0012). Antiadhesion membrane did not reduce the risk for SBO (HR, 1.299; 95% CI 0.683-2.470; p = 0.4246). In the patients belonging to subgroup analyses who received distal and total gastrectomy, the antiadhesion membrane was not associated with the incidence of SBO. Conclusions: Antiadhesion membrane did not decrease SBO occurrence rate after open gastrectomy. Therefore, the use of antiadhesion membrane would not be effective for preventing SBO in gastric cancer surgery.

Protocol digest of a randomized controlled adaptive Phase II/III trial of neoadjuvant chemotherapy for Japanese patients with oesophagogastric junction adenocarcinoma: Japan Clinical Oncology Group Study JCOG2203 (NEO-JPEG).

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

A nonrandomized controlled trial: long-term outcomes of LATG/LAPG for cStage I gastric cancer: Japan Clinical Oncology Group Study JCOG1401.

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

The Effectiveness of Screening Total Colonoscopy for Preoperative Patients with Gastric Cancer.

BACKGROUND: Colorectal cancer (CRC) is the most common cancer that coincides with gastric cancer (GC). Although the usefulness of total colonoscopy (TCS) as a CRC screening tool has been reported in preoperative patients with GC, the long-term outcome of patients with synchronous CRC (SCRC) remains unclear. This study aims to clarify the significance of preoperative screening TCS for GC in terms of survival outcomes. PATIENTS AND METHODS: We included 796 patients who underwent preoperative screening TCS for GC. The risk factors, clinicopathological features, and survival outcome of SCRC were examined. Furthermore, the cost-effectiveness was evaluated from the perspective of improving the rates of mortality caused by CRC. RESULTS: SCRC was observed in 43 patients (5.4%). Endoscopic treatment for SCRC was performed on 30 patients. In total, 15 patients underwent surgical resection, including 2 patients requiring additional surgery after endoscopic treatment. Regarding pathological stages, 25 patients had stage 0, 12 patients had stage I, 5 patients had stage II, and 1 patient had stage IIIB disease. The cumulative mortality rates were as follows: GC-related deaths, 12.6%; deaths from cancers other than CRC, 1%; deaths from other causes, 5.5%. No deaths were attributed to SCRC. Comparing the patients who did not undergo TCS, an incremental cost-effectiveness ratio analysis suggested that a screening cost of 5.86 million yen was required to prevent one CRC death. CONCLUSIONS: Curative treatment was possible in all patients with SCRC. No deaths were attributed to SCRC, suggesting that screening TCS for GC is effective.

5-year follow-up results of a JCOG1104 (OPAS-1) phase III non-inferiority trial to compare 4 courses and 8 courses of S-1 adjuvant chemotherapy for pathological stage II gastric cancer.

BACKGROUND: Postoperative adjuvant chemotherapy with S-1 for 1 year (corresponding to eight courses) is the standard treatment for pathological stage II gastric cancer. The phase III trial (JCOG1104) investigating the non-inferiority of four courses of S-1 to eight courses was terminated due to futility at the first interim analysis. To confirm the primary results, we reported the results after a 5-years follow-up in JCOG1104. METHODS: Patients histologically diagnosed with stage II gastric cancer after radical gastrectomy were randomly assigned to receive S-1 for eight or four courses. In detail, 80 mg/m2/day S-1 was administered for 4 weeks followed by a 2-week rest as a single course. RESULTS: Between February 16, 2012, and March 19, 2017, 590 patients were enrolled and randomly assigned to 8-course (295 patients) and 4-course (295 patients) regimens. After a 5-years follow-up, the relapse-free survival at 3 years was 92.2% for the 8-course arm and 90.1% for the 4-course arm, and that at 5 years was 87.7% for the 8-course arm and 85.6% for the 4-course arm (hazard ratio 1.265, 95% CI 0.846-1.892). The overall survival at 3 years was 94.9% for the 8-course arm, 93.2% for the 4-course arm, and that at 5 years was 89.7% for the 8-course arm, and 88.6% for the 4-course arm (HR 1.121, 95% CI 0.719-1.749). CONCLUSIONS: The survival of the four-course arm was slightly but consistently inferior to that of the eight-course arm. Eight-course S-1 should thus remain the standard adjuvant chemotherapy for pathological stage II gastric cancer.

Neoadjuvant chemotherapy for locally advanced gastric cancer in Japan: Consensus meeting at the 77th general meeting of the Japanese Society of Gastroenterological Surgery.

Treatment strategy for locally advanced gastric cancer differs worldwide. Neoadjuvant chemotherapy (NAC) is considered one of the promising treatment options for locally advanced gastric cancer, even in Japan, and clinical trials have been conducted or are ongoing. A consensus meeting was organized at the 77th general meeting of the Japanese Society of Gastroenterological Surgery in 2022, in which the current status and future prospects of NAC for locally advanced gastric cancer were discussed. Participants at the meeting looked forward to the results of the JCOG1509 trial, providing solid evidence regarding NAC. The optimal indications and regimens for NAC were also debated. Patients with cStage III gastric cancer are the main targets of NAC in Japan, and a doublet regimen of S-1 and oxaliplatin was preferred by the participants. However, the feasibility of a triplet regimen with S-1, oxaliplatin, and docetaxel, and that with 5-FU, leucovorin, oxaliplatin, and docetaxel has been demonstrated, and these could become treatment options in Japan. Other points of discussion include perioperative chemotherapy to avoid peritoneal recurrence and for patients with dMMR/MSI-high tumors. The panel regarded NAC as a promising treatment option, and NAC will become the standard treatment for cStage III gastric cancer in Japan if an ongoing clinical trial successfully demonstrates its efficacy.

Randomized phase II study comparing neoadjuvant 5-fluorouracil/oxaliplatin/docetaxel versus docetaxel/oxaliplatin/S-1 for patients with type 4 or large type 3 gastric cancer.

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