Treatment patterns and survival in older adults with unresected nonmetastatic biliary tract cancers

Introduction: The optimal treatment for unresected nonmetastatic biliary tract cancer (uBTC) is not well-established. The objective of this study was to analyze the treatment patterns and compare the differences in overall survival (OS) between different treatment strategies amongst older adults with uBTC. Materials and methods: We identified patients aged ≥65 years with uBTC using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database (2004–2015). Treatments were classified into chemotherapy, chemoradiotherapy, and radiotherapy. The primary outcome was OS. The differences in OS were analyzed using Kaplan-Meier curves and multivariable Cox proportional hazard regression. Results: A total of 4352 patients with uBTC were included. The median age was 80 years and median OS was 4.1 months. Most patients (67.3%, n = 2931) received no treatment, 19.1% chemotherapy (n = 833), 8.1% chemoradiotherapy (n = 354), and 5.4% radiotherapy alone (n = 234). Patients receiving no treatment were older and had more comorbidities. Chemotherapy was associated with significantly longer OS than no treatment in uBTC (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.79–0.95), but no difference was found in the subgroups of intrahepatic cholangiocarcinoma (iCCA; HR 0.87, 95% CI 0.75–1.00) and gallbladder carcinoma (GBC; HR 1.09, 95% CI 0.86–1.39). In the sensitivity analyses, capecitabine-based chemoradiotherapy showed significantly longer OS in uBTC compared to chemotherapy (adjusted HR 0.71, 95% CI 0.53–0.95). Discussion: A minority of older patients with uBTC receive systemic treatments. Chemotherapy was associated with longer OS compared to no treatment in uBTC, but not in the subgroups of iCCA and GBC. The efficacy of chemoradiotherapy, especially in perihilar cholangiocarcinoma using capecitabine-based chemoradiotherapy, may be further evaluated in prospective clinical trials.