The Role of Adjuvant Chemoradiotherapy in Nonhilar Extrahepatic Bile Duct Cancer: A Long-Term Single-Institution Analysis

Purpose: Despite frequent use in the clinical setting, especially for patients with high-risk factors for relapse, the role of adjuvant treatment has not been clarified in nonhilar extrahepatic bile duct cancer (NH-EHBDC). The goal of this study is to identify the role of adjuvant chemoradiotherapy (CRT) in NH-EHBDC patients after radical surgery. Methods and Materials: Patients with NH-EHBDC who underwent radical surgery from July 2007 to December 2018 were reviewed retrospectively. Univariate and multivariate analyses were conducted to identify prognostic factors for locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS). Subgroup analyses were performed to further identify the role of adjuvant CRT. Results: Three hundred twenty-eight patients were accrued. At a median follow-up of 37.1 months (range, 1.0-144.2 months), the 3-year LRRFS, DMFS, DFS, and OS were 63.4%, 59.0%, 53.2%, and 67.5%, respectively. In multivariate analysis, adjuvant CRT was an independent prognostic factor for LRRFS, DMFS, DFS, and OS (P < .05). For patients with nodal involvement, pT3 stage, tumor size ≥ 5 cm, poorly differentiated tumor, and R1 resection, adjuvant CRT significantly improved DFS (P < .05). Conclusions: In patients with NH-EHBDC, adjuvant CRT significantly improved LRRFS and DFS. For patients with risk factors such as nodal involvement, pT3 stage, poorly differentiated tumor, tumor size ≥ 5 cm, or R1 resection, adjuvant CRT might contribute to improve treatment outcomes.