Adjuvant therapy in localized vs regional biliary tract cancers: A SEER analysis.

Abstract

e16221 Background: Biliary Tract Cancers (BTC) are aggressive malignancies. Treatment of early-stage disease involves surgical resection, but whether adjuvant therapy offers a clear survival benefit remains inconclusive. This study aims to explore the impact of demographic factors and adjuvant therapy on survival outcomes at a population level through the lens of the latest SEER (Surveillance, Epidemiology, and End Results) registries. Methods: Cases were filtered by the following criteria: histologic type (adenocarcinoma), anatomic location (gallbladder, intrahepatic, extrahepatic), stage (local and regional), microscopically confirmed diagnosis, and confirmed surgical resection. Cases with incomplete entries were excluded. A Cox proportional hazard model was used to analyze survival in the context of race, gender, income, and type of adjuvant therapy (none, chemotherapy (AC), chemo-radiotherapy (CRT), and radiation (RT)). Data analysis was performed in RStudio. Results: Between 2005 and 2019, 3565 patients were identified. Patients with regional BTC demonstrated improved median survival with AC (27 vs 23 months, HR 0.72, CI 0.63-0.82, p ≤.05) and CRT (28 vs 23 months, HR 0.63, CI 0.56-0.72, p ≤.05). Median survival in localized BTC was 52 months. Adjuvant therapy of any type did not impact survival for localized BTC. Analysis of race as a covariate in localized BTC showed that all minority groups had improved survival compared to non-Hispanic whites (Asian, HR 0.33; Black, HR 0.50; Hispanic, HR 0.38, p≤.05). In regional gallbladder BTC, this survival benefit was limited to Asians only (HR 0.52, p≤.05). Conclusions: Our data show that AC and CRT may improve survival in patients with regional BTC across all anatomic subtypes. In our cohort, adjuvant therapy had no impact on survival in localized BTC. Differences in outcomes may exist among racial groups for different subtypes of BTC. Future adjuvant clinical trials for BTC should consider stratifying for regional and localized disease. [Table: see text]