Gastrectomy as a secondary surgery for stage IV gastric cancer patients who underwent S-1-based chemotherapy: a multi-institute retrospective study

Background Current advances in chemotherapy provide opportunities for stage IV gastric cancer patients with distant metastasis to undergo potentially curable resection. There are, however, few data on gastrectomy as a secondary surgery aimed at rendering such patients cancer-free. Methods We investigated stage IV gastric cancer patients who underwent surgery with curative intent after S-1-based chemotherapy between 2000 and 2008. Twenty-eight patients from 12 hospitals were enrolled in this study. Factors indicating that the tumors were incurable included clinical stage T4 in 9 patients, para-aortic node metastasis in 15, peritoneal metastasis in 7, and liver metastasis in 4. Results Of the 28 laparotomy patients, 26 underwent complete resection with no residual tumor, obtaining a complete resection rate of 92.9%. There were no in-hospital deaths or reoperations. In four patients, the primary tumor showed pathological complete response. The 1-, 3-, and 5-year overall survival rates after secondary gastrectomy were 82.1, 45.9, and 34.4%, respectively, with a median survival time of 29 months. Univariate analysis revealed histological tumor length, clinical depth of tumor invasion, number of metastatic nodes, pathological depth of tumor invasion, and pathological response to be the factors influencing patient survival after secondary surgery. On multivariate analysis, histological tumor length (5.0 cm or larger) was the only significant prognostic factor (relative risk 3.23, P = 0.028). Conclusions Secondary gastrectomy following S-1-based chemotherapy was a safe and effective treatment for stage IV gastric cancer. Primary tumor size is an indicator for the appropriate selection of patients for this treatment.