Completion of adjuvant S-1 chemotherapy after surgical resection for biliary tract cancer: A single center experience.

BACKGROUNDS:A recent randomized control trial (JCOG1202; ASCOT trial) demonstrated the efficacy of adjuvant S-1 chemotherapy (ASC) for biliary tract cancer (BTC) after surgical resection; however, the significance of the completion of ASC in the real-world setting remains unknown. METHODS:Data of consecutive patients who underwent surgical resection for biliary tract cancer (BTC) from 2011 to 2021 were retrospectively reviewed. Of these, patients who underwent ASC were enrolled in this study. Patients were divided into two groups according to whether ASC was completed: the completion group and the non-completion group. Clinicopathological features and survival outcomes were assessed. RESULTS:Of the 223 patients with BTC who underwent surgical resection, 75 patients who underwent ASC were included for analysis. Among them, 48 (64.0 %) completed the intended ASC course, while 27 cases (36.0 %) discontinued the treatment. The most common reason for the discontinuation was adverse event (n = 16, 59.3 %), followed by disease recurrence (n = 9, 33.3 %). Patients in the completion group showed significantly better overall survival (OS) (p < 0.001) and recurrence-free survival (RFS) (p < 0.001) compared to the non-completion group. Further, after excluding the patients in the non-completion group who discontinued ASC due to disease recurrence, the significance of ASC completion was retained for both OS and RFS. CONCLUSION:The completion of ASC was associated with improved prognosis in patients with BTC after surgical resection. The achievement of ASC should be the goal after surgical resection, while further study may be warranted regarding the resistance of ASC.