Effect of adjuvant radiation on survival for extra-hepatic cholangiocarcinoma.

377Background: Extra-hepatic cholangiocarcinomas (EHC) are low-incidence cancers that are difficult to diagnose and associated with a dismal prognosis. Surgery remains the only option for durable survival however R1 resections are high. We sought to examine the impact of adjuvant therapies on survival in patients with EHC. Methods: Utilizing the National Cancer Database we identified patients who underwent resection for EHC. We then stratified by adjuvant therapy (chemo(AC) or chemoradiation(CRT). Baseline comparisons of patient characteristics were made using Mann-Whitney U, Kruskal Wallis and Pearson’s Chi-square test as appropriate. Survival analyses were performed using the Kaplan-Meier method. Multivariable cox proportional models (MVA) were developed to identify predictors of survival. All statistical tests were two-sided and α < 0.05 was considered significant. Results: We identified 4334 patients who underwent EHC resection: AC = 775, CRT = 1254, no adjuvant (NA) therapy = 2305 and a median age of...