Adjuvant S-1 Versus Gemcitabine for Node-Positive Perihilar Cholangiocarcinoma: A Propensity Score-Adjusted Analysis.

BACKGROUND The efficacy of adjuvant chemotherapy for biliary cancers remains controversial because of conflicting results from previous phase 3 studies that used different key drugs and enrolled patients with heterogeneous tumor sites and disease stages. Fluoropyrimidine seems more beneficial than gemcitabine (GEM) combination regimens in the adjuvant setting; however, data comparing the survival benefit between GEM- and fluoropyrimidine-based regimens are lacking. METHODS Patients who underwent resection for node-positive perihilar cholangiocarcinoma were included. The patients who underwent adjuvant chemotherapy were divided into the S-1 and GEM groups according to the regimen. The recurrence-free survival (RFS) and the overall survival (OS) were compared between the groups and adjusted with propensity scores generated from 14 potentially confounding clinicopathological factors. RESULTS In total, 186 patients (Surgery alone, n = 71; S-1, n = 60; GEM, n = 55) were included. The S-1 and GEM completion rates were 75% and 65%, respectively. Among the patients who underwent adjuvant therapy, the RFS was longer in the S-1 group patients than the GEM group patients (median, 24.4 months vs 14.9 months; P = .044) whereas the OS was not significantly different between the groups (median, 48.5 months vs 35.0 months; P = .324). After propensity score adjustment, the differences in RFS and OS between the groups were more evident (HR: 2.696, 95% CI: 1.739-4.180 P < .001; HR: 1.988, 95% CI: 1.221-3.238, P < .001, respectively). CONCLUSIONS Compared with adjuvant GEM monotherapy, adjuvant S-1 monotherapy may improve survival in node-positive perihilar cholangiocarcinoma patients.