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Resectability status is considered an important indicator for progression of pancreatic cancer. We verified the superior mesenteric artery (SMA) factors of resectability status by radiological and pathological analysis in patients who underwent pancreatoduodenectomy with combined resection of the SMA.We enrolled 22 patients who underwent pancreatoduodenectomy with combined resection of the SMA. Patients were divided into 3 groups according to the contact angle between the tumor and the SMA in preoperative computed tomography images (no contact, R-sma; contact within 180 degrees, BR-sma; contact more than 180 degrees, UR-sma). We pathologically evaluated cancer progression toward the SMA.There were 3 patients with R-sma, 12 with BR-sma, and 7 with UR-sma. The median distance (mm) between the cancer and the SMA was 7.0 with R-sma, 1.0 with BR-sma, and 0 with UR-sma (P = 0.0003). Invasion to the superior mesenteric nerve plexus was positive in none with R-sma, 11 with BR-sma, and 7 with UR-sma (P0.0001). Invasion to the SMA was positive in none with R-sma and BR-sma, and 7 with UR-sma (P0.0001).Superior mesenteric artery factors of resectability status are reliable indicator for cancer progression toward the SMA.

BACKGROUND Lymphatic basin dissection is a sentinel node biopsy method that is specific for gastric cancer. In this method, the dyed lymphatic system is dissected en bloc, and sentinel nodes are identified at the back table (ex vivo). Even with lymphatic basin dissection, blood flow to the residual stomach can be preserved, and function-preserving curative gastrectomy can be performed. The oncological safety of function-preserving curative gastrectomy combined with lymphatic basin dissection has not yet been fully investigated. We hypothesized that the oncological safety of sentinel node navigation surgery (SNNS) is not inferior to that of the guidelines. AIM To investigate the life prognosis of SNNS for gastric cancer in comparison with guidelines surgery. METHODS This was a retrospective cohort study. Patients were selected from gastric cancer patients who underwent sentinel node biopsy from April 1999 to March 2016. Patients from April 1999 to August 2008 were from the Department of Surgery II, Kanazawa University Hospital, and patients from August 2009 to March 2016 were from the Department of Surgical Oncology, Kanazawa Medical University Hospital. Patients who were diagnosed with gastric cancer, which was preoperatively diagnosed as superficial type (type 0), 5 cm or less in length, clinical T1-2 and node negative, and underwent various gastrectomies guided by sentinel node navigation were retrospectively collected. The overall survival (OS) and relapse-free survival (RFS) of these patients (SNNS group) were investigated. Patients with gastric cancer of the same stage and who underwent guidelines gastrectomy with standard nodal dissection were also selected as the control group. RESULTS A total of 239 patients in the SNNS group and 423 patients in the control group were included. Pathological nodal metastasis was observed in 10.5% and 10.4% of the SNNS and control groups, respectively. The diagnostic abilities of sentinel node biopsy were 84% and 98.6% for sensitivity and accuracy, respectively. In the SNNS group, 81.6% of patients underwent modified gastrectomy or function-preserving curative gastrectomy with lymphatic basin dissection, in which the extent of nodal dissection was further reduced compared to the guidelines. The OS rate in the SNNS group was 96.8% at 5 years and was significantly better than 91.3% in the control group (P = 0.0014). The RFS rates were equal in both groups. After propensity score matching, there were 231 patients in both groups, and the cumulative recurrence rate was 0.43% at 5 years in the SNNS group and 1.30% in the control group, which was not statistically different. CONCLUSION The oncological safety of patients who undergo gastrectomy guided by sentinel node navigation is not inferior to that of the guidelines surgery.

Background The multidisciplinary treatment including induction chemotherapy plus conversion surgery (CS) has attracted attention as a new strategy to improve the outcome of metastatic gastric cancer (MGC). However, it is unclear which patients achieve a good response to chemotherapy and successful CS. Tumor-infiltrating immune cells (TIICs) have been reported to be both prognostic and predictive biomarkers not only in immunotherapy but also in chemotherapy in many cancer types. However, there have been no reports on the usefulness of TIICs as biomarkers in conversion surgery for MGC. The aim of the present study was to evaluate the association between the TIICs and treatment outcome for the multidisciplinary treatment in MGC. Methods We retrospectively analyzed 68 MGC patients who received docetaxel plus cisplatin plus S-1 (DCS) therapy between April 2006 and March 2019 in our institute. The number of tumor-infiltrating CD4+, CD8+, Foxp3+lymphocytes, CD68+, CD163+macrophages in pre-treatment endoscopic biopsy samples were evaluated to investigate their predictive value for multidisciplinary treatment. Results Fifty patients underwent CS following DCS therapy (CS group), whereas 18 patients underwent DCS therapy alone (non-CS group). The median survival time (MST) of CS group was 33.3 months, which was significantly longer than the MST of 9.0 months in non-CS group (p +macrophages was extracted as an independent prognostic factor for overall survival in all patients. There were more cases of high infiltration of CD163+macrophages in non-CS group than in CS group. Furthermore, in CS group, pathological responders to DCS therapy showed low infiltration of CD163+ macrophages, and high infiltration of CD8+lymphocyte. CD163 low group showed a significant prolonged survival compared with CD163 high group in patients who underwent CS (p = 0.02). Conclusions The pre-treatment CD163+macrophages infiltration would be a pivotal biomarker for predicting prognosis and pathological response to multidisciplinary treatment among TIICs in MGC. Thus, for patients with low CD163+macrophage infiltration in pre-treatment biopsy sample, diagnostic imaging should be performed frequently during chemotherapy to avoid missing the optimal timing for CS, and CS should be aggressively considered as a treatment option if curative resection is deemed feasible.

Background The lipid scavenger receptor cluster of differentiation 36 (CD36) has been shown to have a pro-metastatic function in several cancers. Adipose tissue, a favorable site for peritoneal metastasis (PM) from gastric cancer (GC), promotes this process by providing free fatty acids (FFAs); however, the role of CD36 in PM progression from GC remains to be elucidated. Materials and Methods We evaluated CD36 expression in the GC cells under various conditions. CD36 overexpressing (CD36OE) MKN45 cells were prepared and their migration and invasive properties were assessed. A PM mouse model was used to investigate the biological effects of palmitic acid (PA) and CD36. Furthermore, we examined the clinical role of CD36 expression in 82 human PM samples by immunohistochemical staining. Results Hypoxia markedly increased CD36 expression in GC cells. In normoxia, only CD36OE MKN45 cells treated with PA showed an increase in migration and invasion abilities. An increased expression of active Rac1 and Cdc42 was observed, which decreased following etomoxir treatment. Conversely, hypoxia increased those capacities of both vector and CD36OE MKN45 cells. In a mouse model transplanted with CD36OE MKN45 cells, more peritoneal tumors were observed in the high-fat diet group than those in the normal diet group. In clinical samples, 80% of PM lesions expressed CD36, consistent with hypoxic regions, indicating a significant association with prognosis. Conclusion Our findings indicate that a hypoxia in the peritoneal cavity induces CD36 expression in GC cells, which contributes to PM through the uptake of FFAs.

Peritoneal metastasis (PM) is one of the most common causes of noncurative surgery and the most frequent recurrence pattern in gastric cancer (GC). During the process of PM, GC cells detached from primary tumor interact with human peritoneal mesothelial cells (HPMC) overlapped with adipose tissues such as the omentum or mesentery. Although the interaction with HPMC promotes the malignancy of GC, the role of adipose tissues remains unclear.We aimed to clarify how adipose tissue are affected by adjacent primary tumors during the expression of adipokines and to elucidate whether GC cells transform adipocytes into CAFs in vitro. In addition, we investigated whether GC cells are affected by adipocytes in their ability to infiltrate.We investigated the phenotypic conversion of adipocytes during the malignant process of GC cells in vivo and in vitro. We evaluated the expression levels of adiponectin in the omental adipose tissue of gastric cancer patients by western blotting. Following adipocytes/gastric cancer cells coculture, adipocyte markers, adiponectin receptors, and inflammatory cytokine markers were detected by real-time PCR and/or western blotting in the single-cultured and co-cultured adipocytes; cancer-associated fibroblast (CAF) markers were detected by immunofluorescence and western blotting in the single-cultured and co-cultured adipocytes; invasion assays were performed in single cultured and co-cultured MKN45 and OCUM.In omental adipose tissues that are situated close to the primary tumors, the expression of adiponectin tended to decrease in patients with subserosal or serosal invasion. By co-culturing with GC cells, adipocytes were dedifferentiated and the expression levels of CAF marker FSP1 and inflammatory cytokines, PAI-1 and IL-6, significantly increased (p 0.05). Furthermore, GC cells co-cultured with adipocytes showed enhanced invasion ability.Our findings suggest that the phenotypic conversion of adipocytes may promote the malignancy of GC in the construction of the cancer microenvironment of PM.

257 Background: NIVO therapy is a standard care treatment for heavily pretreated patients with AGC. Improvement in objective response rate (ORR) to CTx after NIVO therapy for various cancer types has been reported. However, the efficacy and safety of CTx for AGC after progression on NIVO remains unclear. Methods: The REVIVE trial was a prospective, multicenter, observational study that evaluated the efficacy and safety of CTx in NIVO-refractory or NIVO-intolerant patients (pts) with AGC (UMIN000032182). The primary endpoint was overall survival (OS) of CTx following NIVO therapy. The median threshold and expected survival times were set as 4.0 and 7.0 months (M). The secondary endpoints are ORR, disease control rate (DCR), progression-free survival (PFS), and incidence of adverse events (AEs), including immune-related adverse events (irAEs). CTx consisted of irinotecan alone (IRI), trifluridine/tipiracil alone (FT), and oxaliplatin-containing regimens (OX). Results: Of 395 pts treated with NIVO who met the eligibility at formal registration from Jun 2018 to Sep 2020, 199 pts who received CTx after NIVO were evaluated. Pt characteristics were as follows: median age, 69 years; male, 70%; ECOG PS 0/1/2, 38/51/12%; histology (diffuse/intestinal), 39/59%; metastatic lesions (peritoneum/liver/lung), 38/34/15%; number of metastatic organ sites (0–1/≥2), 40/60%; measurable lesions, 83%; and CTx regimens (IRI/FT/OX), 64/31/5%. Median OS and PFS were 7.5 M (95%CI, 6.7–9.7) at 145 events for OS and 2.9 M (95%CI, 2.2–3.5) at 184 events for PFS. The ORR and DCR were 17.0% (95%CI, 11.6–23.6) and 46.7% (95%CI, 38.9–54.6). Median OS, median PFS, ORR, and DCR according to CTx regimens (IRI/FT/OX) were 8.1/7.1/6.2 M, 3.3/2.8/2.4 M, 18.9/10.9/25.0%, and 47.8/43.5/50.0%, respectively. At the start of CTx, 42 pts had irAEs due to prior NIVO therapy. The most common any-grade and grade ≥3 AEs during CTx included decreased appetite (46% and 7.5%), fatigue (26% and 2.5%), nausea (24% and 1.5%), constipation (16% and 0%), and diarrhea (28% and 4.0%). No treatment-related deaths were observed. Conclusions: Prior NIVO therapy may lead to improved prognosis after CTx without unexpected AEs in pts with AGC, warranting further investigations after NIVO is approved as first-line treatment.[Table: see text]