Yukinori Yamagata

Introduction: Mixed neuroendocrine–non-neuroendocrine neoplasms (MiNENs) are rare tumors composed of neuroendocrine and non-neuroendocrine components. Their occurrence in the duodenum is extremely uncommon. Preoperative diagnosis is difficult because the neuroendocrine component may not be detected in biopsy specimens. We report a rare case of non-ampullary duodenal MiNEN initially diagnosed as adenocarcinoma. Case presentation: A 56-year-old man was found to have a tumor in the duodenal bulb during routine endoscopic examination. Biopsy revealed moderately to poorly differentiated adenocarcinoma, and computed tomography demonstrated bulky regional lymph node metastasis without distant disease. Neoadjuvant chemotherapy with S-1 plus oxaliplatin was administered based on treatment strategies used for advanced gastric cancer in Japan. Post-treatment evaluation showed stable disease, and pancreaticoduodenectomy with regional lymph node dissection achieved R0 resection. Histopathological examination revealed both adenocarcinoma and neuroendocrine carcinoma (NEC) components, leading to a diagnosis of MiNEN. Lymph node metastases demonstrated component-specific heterogeneity, with NEC involvement in station No. 8a and adenocarcinoma in the remaining metastatic nodes. Postoperative platinum-based chemotherapy was administered, and the patient remains recurrence-free at 16 months after surgery. Discussion: Duodenal MiNEN presents diagnostic and therapeutic challenges because biopsy specimens may fail to detect the neuroendocrine component preoperatively. In the present case, component-specific lymph node metastases suggested biological heterogeneity and may have influenced treatment selection. Conclusion: Non-ampullary duodenal MiNEN is a rare and diagnostically challenging disease. This case highlights the importance of accurate pathological evaluation and multidisciplinary management.

Background: Robotic gastrectomy has been adopted for gastric cancer. However, operative time remains longer than that of laparoscopic surgery. Junk time has been proposed as a major contributor to prolonged operative duration. This study evaluated intraoperative time structure during the initial clinical experience with the minimally invasive laparoscopic and robotic (MILAR) approach using the da Vinci SP system. Methods: This retrospective exploratory workflow analysis included consecutive patients who underwent robot‐assisted distal gastrectomy with D1+/D2 lymphadenectomy between May 2024 and June 2025. Patients were divided into the SP (MILAR) group and the conventional multi‐port robotic (Xi) group. Operative videos from skin incision to gastric transection were reviewed to quantify effective time and junk time. Results: A total of 40 patients were analyzed (SP, n = 11; Xi, n = 29). Total operative time was significantly shorter in the SP group than in the Xi group (148.0 vs. 204.0 min, p = 0.001). Junk time was significantly reduced (30.4 vs. 36.6 min, p = 0.034), accompanied by fewer robotic instrument exchanges (4 vs. 46, p < 0.001). Effective time was shorter in the SP group; although this finding may have been influenced by surgeon expertise and case complexity. No increase in procedure‐related complications was observed in the SP group. Conclusions: The present exploratory study describes differences in intraoperative time structure observed during the initial clinical experience with the MILAR approach using SP system. These findings provide insight into workflow characteristics of a hybrid team‐based approach and warrant further evaluation in prospective studies.

Background: Nivolumab‐including chemotherapy (nivo‐CTX) for stage IV gastric cancer (GC) may increase the chance of conversion surgery but risk of immune‐related adverse events (irAEs) during perioperative period remains unclear. Methods: We examined irAEs in 36 patients with marginally resectable GC who received nivo‐CTX followed by surgery between November 2021 and March 2024. Results: Marginally resectable factors were para‐aortic lymph node in 23, liver in 3, esophageal intramural metastasis in 2, mediastinal lymph node in 1, peribiliary lymph node in 1, P1b in 2, Bulky N in 5, and T4b in 1. IrAE was observed in 12 patients (33.3%). Among 12 patients, irAE was detected during chemotherapy in 6 patients (50%), after chemotherapy to admission to surgery in 2 (16.7%), and after surgery in 4 (33.3%). Grade 2 irAE was found in 6 patients (16.7%); rash in 6 and thyroiditis in 2, grade 3 was in 3 (8.3%); adrenal insufficiency in 1, hepatitis in 1, and pituitary insufficiency in 1, grade 4 was in 3 (8.3%); type 1 diabetes mellitus in 2, pemphigus in 1, and encephalitis in 1. Grade 3 or 4 irAE was found in 6 patients (16.7%). Among the patients who had irAE, grade 3 or 4 was detected in 2 of 6 during chemotherapy (33.3%) but was in 3 of 4 (75%) after surgery. Conclusions: IrAE was frequently observed not only during chemotherapy but also during perioperative period. Surgeons must pay special attention to unfamiliar irAE events during perioperative period.

Background Gastric neuroendocrine carcinoma (NEC) is a rare and aggressive malignancy for which no standard treatment has been established for locoregional disease. This multicenter retrospective study aimed to evaluate the prognostic relevance and therapeutic efficacy of lymph node dissection in this setting. Methods A total of 118 patients with gastric NEC or mixed adenoneuroendocrine carcinoma (MANEC) who underwent gastrectomy with lymph node dissection were analyzed. Survival outcomes, clinicopathological factors, and the therapeutic value index of each lymph node station were assessed. Lymph node involvement was classified using both the pathological N category and the extent of nodal involvement based on the dissection area (pND). Results The 5-year overall survival and 3-year recurrence-free survival rates were 56.7% and 63.4%, respectively. Prognostic stratification using pND provided clearer separation than using the conventional pN category. Multivariate analysis identified older age, female sex, and pND2 (metastasis to D2 area nodes) as independent unfavorable prognostic factors. The therapeutic value index for lymph nodes in the D1 area was high (35.0, based on 5-year overall survival), whereas the index for D2 nodes was markedly lower (6.8). Notably, these indices remained consistent across histological subtypes, showing similar values between NEC and MANEC. Postoperative chemotherapy and surgical complications did not significantly affect survival outcomes. Conclusions Perigastric (D1) lymph node dissection appears to provide meaningful survival benefit in locoregional gastric NEC, whereas the additional value of D2 dissection is limited. These findings support consideration of a more selective surgical approach, though further validation is needed.

Ishizu K, et al. J Gastric Cancer. 2025 May;25:e29. https://doi.org/10.5230/jgc.2025.25.e29

Background: Robotic surgery may have shown advantages over conventional laparoscopic surgery, but the da Vinci SP system, which utilizes a single incision, has had limited use in gastric cancer surgery. This study aims to evaluate the short‐term outcomes of a novel hybrid technique, minimally invasive laparoscopic and robotic surgery (MILAR), with the da Vinci SP system for gastric cancer. Materials and Methods: This retrospective study reviewed 23 consecutive patients who underwent gastrectomy for gastric cancer using the MILAR technique with the da Vinci SP system between May and October 2024. Operative time, blood loss, and morbidity were analyzed. Results: The median operation time was 192 min (191 min for distal gastrectomy, 174 min for proximal gastrectomy, and 308 min for total gastrectomy). Blood loss was minimal, with a median of 13 mL and no patient exceeding 250 mL. Postoperative complications were also minimal; one patient developed a grade II intra‐abdominal fluid infection and another had grade II enteritis. There were no anastomotic leakages or pancreatic fistulas, and no grade III or higher complications were observed. Conclusions: MILAR using the da Vinci SP system is feasible and safe for gastric cancer surgery, with minimal blood loss and acceptable operative times. This is the first report from Japan showing the successful application of this system in gastric cancer, offering new prospects in minimally invasive surgery.

Introduction: The da Vinci SP (SP) has only 1 robotic arm, containing 4 channels. It provides a wide space for assistant surgeons using laparoscopic forceps. We performed a new type of minimally invasive surgery using laparoscopy and a robot (MILAR) utilizing the SP in distal gastrectomy for gastric cancer. Materials and Surgical Technique: An incision at the umbilicus was made for the SP, and 2 ports were inserted from the right abdomen for laparoscopic surgery. In the above view, where surgeons look down at the surgical field, the scope was inserted from the channel at 12 o'clock, and the round tooth retractor was inserted from 6 o'clock. In the below view, where surgeons look up at the surgical field, the scope and retractor were inserted from opposite directions. The robotic operator uses 3 forceps and a scope. The laparoscopic operator uses 2 forceps. On the greater curvature side, the left or right epiploic artery pedicles was retracted by the robot operator under the below view. The suprapancreatic area was dissected with the pedicle of the left gastric artery retracted by the laparoscopic operator under the above view. Discussion: By setting the scope and the retractor in a diagonal direction of 12–6 o'clock, robotic surgeons have a wide space bilaterally for using forceps for nodal dissection under the co‐axial setting. Laparoscopic surgeons can use this space easily. Gastrectomy by MILAR using SP could provide quality surgery within a short operative time.