Positive cystic duct margin at index cholecystectomy in incidental gallbladder cancer is an important negative prognosticator

Abstract Background Prognostic factors following index-cholecystectomy in patients with incidental gallbladder cancer (IGBC) are poorly understood. The aim of this study was to assess the value of the initial cystic duct margin status as a prognosticator factor and to aid in clinical decision making to move forward with curative intent oncologic extended resection (OER). Methods This retrospective study included patients with IGBC who underwent subsequent OER with curative intent at 2 centers (USA and Chile) between 1999 and 2016., Patients with and without evidence of residual cancer (RC) at OER were included. Pathologic features were examined, and predictors of overall survival (OS) were analyzed. Results The study included 179 patients. Thirty-three patients (17%) had a positive cystic duct margin at the index cholecystectomy. Forty-two patients (23%) underwent resection of the common bile duct. OS was significantly worse in the patients with a positive cystic duct margin at index cholecystectomy (OS rates at 5 years, 34% vs 57%; p = 0.032). Following multivariate analysis, only a positive cystic duct margin at index cholecystectomy was predictive of worse OS in patients with no evidence of residual cancer (RC) at OER (hazard ratio, 1.7 95%CI 1.04–2.78; p = 0.034). Conclusions A positive cystic duct margin at index-cholecystectomy is a strong independent predictor of worse OS even if no further cancer is found at OER. In patients with positive cystic duct margin and no RC at OER common bile duct resection leads to improved outcomes.