Limited Use of Adjuvant Therapy in Patients with Resected Gallbladder Cancer Despite a Strong Association with Survival

Background: There are no randomized data to guide clinicians treating patients with gallbladder cancer (GBC). Several retrospective studies reported the survival benefits of adjuvant radiotherapy (RT) and chemoradiation (CRT). In this paper, we examine whether these publications have impacted the utilization of adjuvant therapies and whether their survival benefits are evident in a contemporary cohort of patients. Methods: Using the National Cancer Data Base, we identified 5029 patients diagnosed with T1â €3N0â €1 GBC and treated with surgical resection from 2005 to 2013. We described trends in receipt of adjuvant treatments for three time periods (2005-2007, 2008-2010, 2011-2013) and calculated three-year overall survival (OS) probabilities for 2989 patients treated in 2005-2010. All statistical tests were two-sided. Results: The percentage of patients who received no adjuvant treatments was unchanged from 2005 to 2013. Adjuvant RT decreased from 4.2% to 1.7% (P <.001), adjuvant chemotherapy increased from 8.3% to 13.8% (P <.001), and adjuvant CRT remained stable at 15.9% (P =.98). Adjuvant treatments were associated with improved three-year OS, with adjusted hazard ratio of 0.47 (95% confidence interval [CI] = 0.39 to 0.58) for CRT, 0.77 (95% CI = 0.61 to 0.97) for chemotherapy, and 0.63 (95% CI = 0.44 to 0.92) for RT. Adjuvant CRT was associated with improved survival in all categories, except T1N0, and in patients with negative and positive margins. Conclusion: Over the past decade there was no increase in the utilization of adjuvant therapies in the United States for patients with resected GBC. Adjuvant therapy is associated with statistically significantly improved three-year OS. This analysis should form the basis for current clinical recommendations and support future prospective trials.