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

Abstract

377 Background: 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 67 (18-90) years. R0 resections was performed in 71.6% of patients and the median LN harvest was 9 (3-18). R0 resections and lymph node negative patients demonstrate improved survival p < 0.001 and p < 0.001. Adjuvant therapy did not improve survival in R0 resections, p = 0.2. However survival was benefited in R1 patients, with those receiving CRT demonstrating the most significant improvement: median and overall 5-year survival AC = 16.7 months 8%, CRT = 23.1 months, 20.4%, and NA = 16.1 months and 11.6% p < 0.001. In LN- patients CRT (47.3 months, 47%) but not AC (45 months, 44.5%) demonstrated benefit in survival compared to NA (37.8 months, 40.1) p = 0.04 and p = 0.7. Additionally, patients with LN+ and R1 resection had survival benefit when treated with (CRT 24.9 months and 24.3%), compared to NA (20.2 and 21.1%), p = 0.02. AC (24 months and 24%) did not demonstrate survival in these patients, p = 0.21. MVA demonstrated that age, T-stage, LN+, R0 resection and CRT were predictors of survival. Conclusions: Adjuvant CRT improves survival for patients with EHC who underwent R1 resections, and in LN- and LN+ patients. However, AC only benefited node positive patients with R0 resections. Patients with resected EHC should be referred for adjuvant CRT.