Curative resection for hilar cholangiocarcinoma: Does adjuvant therapy impact overall survival? A multi-institution analysis from the U.S. Extrahepatic Biliary Malignancy Consortium.

Abstract

388 Background: Surgical resection is the cornerstone of curative therapy for localized hilar cholangiocarcinoma. However, the effect of adjuvant therapy (AT) on survival is unclear. We analyzed the impact of AT on overall survival (OS) in those patients undergoing curative resection for hilar cholangiocarcinoma. Methods: We reviewed 294 patients who underwent curative resections for hilar cholangiocarcinoma between 1998 and 2015 from ten institutions participating in the U.S Extrahepatic Biliary Malignancy consortium. We analyzed the impact of AT on the primary outcome of OS. Probability of OS was calculated in the method of Kaplan and Meier and analyzed using multivariate Cox regression analysis. Statistical significance was set at p≤0.05. Results: Mean age was 65 years. OS at 5 years was 16%. A total of 146 patients (50%) received AT. Of these patients, 44 patients underwent solely chemotherapy, 5 underwent only radiation therapy (XRT), and 97 underwent combined therapy. On univariate analysis, patients who received AT and those who did not had similar demographic and preoperative features, with the major difference being in the rate of lymph node (LN) positive disease (50% AT group vs. 19% no AT group, p<0.01). In a multivariate Cox regression analysis, AT conferred a significant protective effect on OS (HR 0.578, p<0.01, 95% CI 0.38-0.86), even when adjusting for age, tumor size, R0 resection status, ASA classification, and LN positivity (Table). Conclusions: AT is associated with improved OS in resected hilar cholangiocarcinoma. This association remains even after adjusting for poor prognostic features. We acknowledge that there is an inherent selection bias when looking at those who underwent AT, and thus future prospective randomized trials are needed. [Table: see text]