Multi‐institutional analysis of the prognostic significance of postoperative complications after curative resection for gastric cancer

Background Insufficient data are available on the prognostic significance of complications after resection of gastric cancer. Therefore, we aimed to assess this gap in our knowledge by studying patients with resectable gastric cancer. Methods A multi‐institutional retrospective database comprising clinical information of 3575 patients who received resection of gastric cancer from 2010 to 2014 at nine institutions. Grades 2 or greater complications of the Clavien‐Dindo classification were judged as clinically relevant postoperative complications, and their associations with postoperative survival were assessed. We assessed the effect of complications on times of initiation and continuation of postoperative adjuvant chemotherapy by S‐1. Results A total of 2954 patients were included in the analysis. Clinically relevant postoperative complications occurred in 664 (23%) patients. Patients’ recurrence‐free survival rate incrementally decreased as the grade of complications became greater. Patients with abdominal complications (eg, leakage of pancreatic fluids, intra‐abdominal abscess, and anastomotic leakage) and those with nonabdominal complications (eg, pneumonia) experienced worse recurrence‐free survival compared to those without complications. Patients who had complications were generally at greater risk of disease recurrence, except for those who underwent laparoscopic surgery and those with pathological stage I. Delayed initiation and shorter continuation of adjuvant S‐1 chemotherapy was experienced by patients with postoperative complications. Conclusions Postoperative complications adversely affected the prognosis in patients with resectable gastric cancer.