Perihilar cholangiocarcinoma: microscopic positive margin and its clinical relevance

The prognostic impact of positive bile duct margins (R1) after resection of perihilar cholangiocarcinoma (PHC) remains unclear, and evidence on the role of adjuvant radiation (RT) is limited.

We retrospectively reviewed 110 patients who underwent curative-intent resection for PHC from 1997 to 2018. Primary outcomes were overall survival (OS) and disease-free survival (DFS). Univariate and multivariate analyses were performed to identify risk factors of OS and DFS.

R1 margins were present in 50 patients (45.5 %). Median OS and DFS for the cohort were 47.5 and 30.2 months. OS and DFS did not differ by margin status. On multivariable analysis, lymph node metastasis independently predicted worse OS (HR 3.81; p < 0.001) and DFS (HR 3.32; p = 0.001), while larger tumor size predicted recurrence (HR 3.12; p = 0.001). Adjuvant chemotherapy was associated with improved OS (HR 0.45; p = 0.049). Among R1 patients, adjuvant RT was associated with longer DFS (68.6 vs 17.8 months; p = 0.049) but not OS.

R1 resection was not associated with inferior survival in this cohort. Lymph node metastasis was the strongest prognostic factor. Adjuvant RT was associated with improved DFS in the R1 patients, supporting its use for local control and warranting prospective validation.