Efficacy and safety of S-1 following gemcitabine with cisplatin for advanced biliary tract cancer.

Background Combination therapy of gemcitabine with cisplatin (GC) is a standard first-line therapy for unresectable or recurrent biliary tract cancer (BTC). S-1 is often used as a second-line therapy in clinical practice, based on the results of some clinical studies investigating its efficacy and safety following gemcitabine monotherapy. However, few studies have reported on the clinical outcomes of S-1 following GC. The purpose of this study was to elucidate the efficacy and safety of S-1 following GC for unresectable and recurrent BTC. Methods We retrospectively collected the data of 116 patients (pts) who were treated with S-1 as a second-line therapy following GC for unresectable or recurrent BTC at Shizuoka Cancer Center (November 2009 to July 2019). Results Of these 116 pts., 84 were assessable. Patient characteristics were as follows: intrahepatic bile duct/extrahepatic bile duct/gallbladder cancer, 30/23/31 pts.; metastatic/recurrent/locally advanced, 57/17/10 pts. The median time to treatment failure and overall survival were 2.5 and 6.0 months, respectively. Among 65 pts. with measurable lesions, the overall response rate was 3.1% (2/65 pts) and the disease control rate was 24.6% (19/65 pts). The common grade 3/4 toxicities included anemia (12%), neutropenia (4%), infections (16%), fatigue (6%), and diarrhea (4%). Dose reduction or treatment schedule modification of S-1 was required in 29 pts. (34.5%), and 17 pts. (20%) terminated S-1 due to adverse events. Conclusions The efficacy and safety of S-1 following GC were almost the same as those of S-1 following GEM monotherapy for unresectable or recurrent BTC.