Adjuvant treatment for the elderly patient with resected gallbladder cancer: a SEER-Medicare analysis

Background: In patients with resected gallbladder cancer (GBC), the role of adjuvant chemotherapy (aCT) remains ill-defined, especially in elderly patients. This study evaluates the value of aCT in elderly patients with GBC and assesses response according to tumor stage. Methods: Patients of >= 65 years of age with resected GBC diagnosed from 2004-2015 were identified using a Surveillance, Epidemiology and End Results (SEER)/Medicare linked database. After propensity score matching, survival of patients treated with aCT was compared to survival of patients who did not receive aCT using Kaplan-Meier and Cox proportional hazards analysis. Results: Of 2,179 patients with resected GBC, 876 (25%) received aCT. In the full cohort of 810 propensity-score matched patients, survival did not differ between patients treated with aCT (17.6 months ) and without aCT (19.5 months, P=0.7720). Subgroup analysis showed that survival was significantly better after aCT in T3/T4 disease (12.3 vs. 7.2 months, P=0.013). Interaction analysis showed that benefit of aCT was primarily seen in combined T3/T4, node-positive disease (HR 0.612 , P=0.006). Conclusions: In this large cohort of elderly patients with resected GBC, aCT was not associated with increased survival. However, aCT may provide a survival benefit in T3/4, node-positive disease.