Conversion Gastrectomy For Stage Iv Unresectable Gastric Cancer: A Retrospective Cohort Study

298 Background: Stage IV Gastric cancer (GC) is a heterogeneous biological condition with a mixture of distant metastases, including hematologic, lymph nodal and/or peritoneal. In the recent classification introduced by Yoshida et al with the proposal to identify objective principles for conversion surgery, stage IV GC patients were subdivided into 4 new categories. In this study, we retrospectively investigated the efficacy of conversion gastrectomy for stage IV GC patients, with particular focus on the Yoshida’s classification. Methods: A retrospective, single center cohort study was performed in patients who had undergone conversion gastrectomy between 2005 and 2018. Data were extracted from Hokkaido Cancer Center database including all metastatic gastric cancer patients submitted to surgery. Only stage IV unresectable tumors/metastases which became resectable after chemotherapy were included in this analysis. Results: Forty-two resected stage IV GC patients were included in this analysis. Median overall survival (OS) was 40.0 months and 1-, 3- and 5-year survivals were 92.9, 70.7 and 57.7%, respectively. Univariate analysis among the patients with conversion gastrectomy identified macroscopic type, clinical response to 1st line therapy, pathological tumor depth, pathological nodal stage, R0 resection as significant prognostic factors. The MSTs of the patients with conversion gastrectomy for each category were 50.1 months for category 1, 46.6 months for category 2, 22.7 months for category 3 and 17.2 months for category 4. Conclusions: Unresectable stage IV GC patients could benefit from radical surgery after chemotherapy and achieve long survivals. Adequate selection of stage IV GC patients for conversion therapy may be an important role.