A multicenter study on adjuvant chemotherapy of S-1 versus observation for resected perihilar cholangiocarcinoma.

Abstract

e16201 Background: The prognosis of perihilar cholangiocarcinoma (PHC) is poor even after curative resection. The efficacy of adjuvant S-1 chemotherapy for resected PHC is unclear. This study aimed to assess the efficacy of adjuvant S-1 chemotherapy after major hepatectomy for PHC. Methods: Consecutive patients with PHC who underwent major hepatectomy (hemihepatectomy or trisectionectomy extending to segment 1 with extrahepatic bile duct resection) at three high-volume centers in Japan from 2007 to 2020 were retrospectively evaluated. Patients with Clavien-Dindo grade V complications, pStage I or IVB disease, and those who underwent adjuvant radiation therapy were excluded from analysis. Propensity score matching analysis was performed to compare the disease-specific survival (DSS) of patients who underwent adjuvant S-1 chemotherapy with those who underwent observation. Results: Of 480 patients, 373 were eligible for the study, 81 of whom underwent adjuvant S-1 chemotherapy, and 146 underwent observation. In the global cohort, DSS in the S-1 and observation groups were similar ( P = 0.18). In the matched cohort as well (S-1: n=44, Observation: n=44), DSS was similar between the S-1 and observation groups ( P = 0.09). On multivariate analysis, performance of percutaneous biliary drainage, CA19-9 levels at operation ≥ 300 U/ml, and lymph node (LN) metastasis were independent predictors of poor survival following major hepatectomy for PHC. In subgroup analysis of patients with LN metastasis, DSS in the S-1 group was better than in the observation group ( P = 0.001). Conclusions: Adjuvant S-1 chemotherapy after major hepatectomy might be effective in PHC patients with LN metastasis.