Background : Although in most countries cholangiocarcinoma (CCA) is a rare cancer, South Korea has the highest incidence of CCA worldwide. Recent studies have been published on the role of adjuvant chemotherapy (AC) in CCA; however, there are challenges in generalizing the findings due to different prognostic characteristics depending on tumor location and the resectability. Therefore, the aim of this study was to investigate the role of AC in distal cholangiocarcinoma (dCCA), one of the most common tumor types among CCA patients.

Methods : The prospectively collected database was retrospectively analyzed. This study included 578 patients with dCCA who underwent curative surgery at Seoul National University Hospital between January 2000 and December 2021. Resection type determination was dependent on the location and extent of the tumor.

Results : The mean age was 66.2 ± 8.9 years, and 410 patients (70.9%) were male. The R0 rate was 87.5% (506 of 578) and 271 patients (46.9%) underwent AC. AC was associated with improved 5-year overall survival (OS) rates (46.6% vs 56.8%, P < 0.001), particularly in advanced T stage (≥ T3) (32.4% vs 56.5%; P < 0.001). Furthermore, AC improved 5-year recurrence-free survival (RFS) in patients with advanced T stage (median, 14.3 vs 51.5 months; P < 0.001) and node-positive disease (median, 10.4 vs 23.7 months; P < 0.001). Multivariate analysis showed that high tumor marker levels, poorly differentiation, positive resection margin, advanced T stage, and node-positive disease were independent negative prognostic factors for both OS and RFS. Conversely, AC was independent positive prognostic factor.

Conclusions : AC improved postoperative survival in patients with dCCA, particularly those with advanced T stage, node-positive disease. These findings support the implementation of AC in the postoperative management of dCCA to improve survival.