Impact of postoperative complications on survival outcomes in patients with gastric cancer: exploratory analysis of a randomized controlled JCOG1001 trial.

BACKGROUND: Recent studies have found a negative impact of postoperative complications on long-term survival outcomes, but it has not been confirmed by data obtained from a prospective study with a large sample size. This study investigated the impact of postoperative complications on long-term survival outcomes, and considered the optimal definition of complication, using data from JCOG1001, which compared bursectomy and non-bursectomy for patients with cT3/4a locally advanced gastric cancer. METHODS: This study included 1191 of 1204 patients enrolled in the JCOG1001 trial. Complications were graded by Clavien-Dindo (C-D) classification. Impact of the grade (≥ C-D grade II or ≥ grade III) or type (any or intra-abdominal infectious) of complication on survival outcome was evaluated by univariate and multivariable analyses using the Cox proportional hazard model. RESULTS: The incidence of any ≥ C-D grade II and ≥ grade III complication was 23.0% and 9.7%, respectively, and that of ≥ grade II and ≥ grade III intra-abdominal infectious complication was 13.4% and 6.9%, respectively. Multivariable analysis showed all four definitions of complications were independent prognostic factors for overall survival. Conversely, only any ≥ C-D grade III complication was found to be an independent prognostic factor for relapse-free survival (hazard ratio, 1.445; 95% confidence interval, 1.026-2.036; P = 0.035). CONCLUSIONS: Postoperative complications adversely affect the long-term survival outcomes of patients with cT3/4a gastric cancer. Any ≥ C-D grade III complication seems to be the most suitable definition of complication for predicting negative long-term survival outcomes.