Survival benefit with adjuvant radiotherapy after resection of distal cholangiocarcinoma: A propensity-matched National Cancer Database analysis

Abstract

Background: No convincing evidence for the benefit of adjuvant radiotherapy (RT) following resection of distal cholangiocarcinoma (dCCA) exists, especially for lower-risk (margin- or node-negative) disease. Hence, the association of adjuvant RT on survival after surgical resection of dCCA was compared with no adjuvant RT (noRT). Methods: Using National Cancer Database data from 2004 to 2016, patients undergoing pancreatoduodenectomy for nonmetastatic dCCA were identified. Patients with neoadjuvant RT and chemotherapy and survival <6 months were excluded. Propensity score matching was used to account for treatment-selection bias. A multivariable Cox proportional hazards model was then used to analyze the association of adjuvant RT with survival. Results: Of 2162 (34%) adjuvant RT and 4155 (66%) noRT patients, 1509 adjuvant RT and 1509 noRT patients remained in the cohort after matching. The rates of node-negative disease (N0), node-positive disease (N+), and unknown node status (Nx) were 39%, 51%, and 10%, respectively. After matching, adjuvant RT was associated with improved survival (median, 29.3 vs 26.8 months; P