The clinical significance of potentially curative resection for gastric cancer following the clearance of free cancer cells in the peritoneal cavity by induction chemotherapy

Purpose The aim of this study was to evaluate the significance of the conversion of the peritoneal cytology from positive to negative following induction chemotherapy in relation to the prognosis after subsequent resection for gastric cancer. Methods This retrospective study was conducted using a prospectively maintained database. A total of 47 patients with free cancer cells in the peritoneal cavity, as evaluated by staging laparoscopy, but no other evidence of distant metastasis, who underwent induction chemotherapy followed by surgery were enrolled in the study. Then, the clinicopathological factors and survival in the study subjects were assessed. Results The median survival time and 5-year overall survival rate of the 47 study participants were 20.4 months and 25.0 %, respectively. In 23 of the patients, the peritoneal cytology converted from positive to negative after the induction chemotherapy, and a microscopically margin-negative gastrectomy was performed. The median survival time of 30.4 months and the 5-year survival rate of 34.6 % of these patients was significantly more favorable than the corresponding values of 15.0 months and 17.6 % in the patients who had persistently positive cytology (P = 0.03). Conclusion Based on our findings, the clearance of free cancer cells in the peritoneal cavity by induction chemotherapy improves the prognosis of patients following subsequent gastrectomy.