Adjuvant S-1 vs 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.