An analysis of a second-line S-1 monotherapy for gemcitabine-refractory biliary tract cancer

Background/Aims: Gemcitabine is widely used as a first-line therapy for biliary tract cancer (BTC). However, few studies have been conducted to analyze second-line therapies. Methodology: From 33 patients who had been administered gemcitabine following resection between May 2005 and August 2007, we retrospectively analyzed the safety and efficacy of S-1 in 11 cases who received S-1 as second-line therapy due to recurrence or relapse of the primary disease. Results: Among the adverse events (AEs) observed during S-1 administration, the most common was a decrease in the concentration of hemoglobin, followed by thrombocytopenia. No Grade 4 AEs or worse were detected. In addition, the AEs and their respective severity strongly resembled those of gemcitabine used as a first-line therapy. There were 7 cases that could be evaluated according to RECIST criteria, of which 1 was considered in the partial response and 3 as stable disease. The medians of time to progression after S-1 administration and survival after S-1 administration were 5.6 months and 31 months, respectively. Conclusions: S-1 could be taken safely as a second-line therapy without provoking severe AEs. By preventing the cessation of S-1 administration due to its AEs, more continued S-1 administration could lead to a better prognosis for BTC.