BILCAP trial and adjuvant capecitabine in resectable biliary tract cancer: reflections on a standard of care

Biliary tract cancer (BTC) is a heterogeneous group of aggressive malignancies comprising ampulla of Vater cancer, gallbladder cancer, extrahepatic cholangiocarcinoma, and intrahepatic cholangiocarcinoma; unfortunately, the incidence of distant and locoregional recurrence remains high in resected BTCs, with approximately 60-70% of the patients who will experience disease relapse. Until a few years ago, adjuvant treatment was mainly based on the results of a meta-analysis including heterogeneous retrospective studies and showing a survival benefit in the selected populations of resected BTC patients with node-positive disease and/or R1 resection. More recently, the results of several prospective randomized clinical trials have been presented and published. Among these, although the randomized phase III BILCAP trial comparing adjuvant capecitabine versus placebo failed to meet its primary endpoint by intention-to-treat analysis, the preplanned sensitivity analysis highlighted a survival benefit, leading to the wide adoption of capecitabine as adjuvant treatment. However, several unanswered questions remain, including the following: may standard capecitabine represent the effective, real standard of care in this setting? Herein, we discuss the results of the BILCAP study, with a particular focus on the impact the trial had in everyday clinical practice worldwide.