Assessing the effectiveness of adjuvant chemoradiotherapy after cholecystectomy in patients with gallbladder cancer.

Abstract

455 Background: The study was conducted to compare the overall survival for patients receiving concurrent chemoradiotherapy (CCRT) versus radiotherapy (RT) or chemotherapy (CT) alone after cholecystectomy in patients with gallbladder cancer. Methods: Patients with gallbladder cancer who had surgical resection from 2004 to 2015 were identified in the National Cancer Database. The proportional hazards assumption for each predictor was assessed using Martingale residuals. Significance was then determined using univariable and multivariable Cox proportional hazards frailty models that allow for clustering of patients within their treatment facility type. Results: A total of 7,258 gallbladder cancer patients who had undergone cholecystectomy met eligibility criteria: 1,509 (20.8%) received CCRT, 283 (3.9%) received RT alone, 1,368 (18.9%) received CT alone, and 4,098 (56.5%) received no adjuvant therapy. The median survival for this patient sample was 29.11 months with median follow-up of 59.10 months. On multivariable analysis, the hazard of death at any given time for patients who received adjuvant CCRT following surgery was 20% (HR = 0.80, 95 CI: 0.73-0.87) lower than those who only underwent surgery alone (p < .0001). By contrast, the hazard of death at any given time for patients who received CT following surgery was 33% (HR = 1.33, 95 CI: 1.22-1.44) higher than those who only underwent surgery (p <.0001). Conclusions: CCRT is associated with improved OS compared with CT or RT alone after cholecystectomy in patients with gallbladder cancer, suggesting that adjuvant CCRT should be used in this population although prospective data is needed to validate these findings.