Impact of Resection Margin Status on Recurrence and Possible Candidates for Adjuvant Radiotherapy in Resected Distal Cholangiocarcinoma

Objective: To evaluate the prognostic impact of resection margin in distal cholangiocarcinoma (dCC). Background: Due to the relatively low prevalence of dCC in Western countries and the use of various definitions of resection margin status, the prognostic impact of bile duct resection margin status remains unclear. Methods: This study included consecutive patients who underwent curative surgery and were diagnosed with dCC between 2000 and 2022. Bile duct resection margin status was classified as clear margin, low-grade dysplasia (LGD), high-grade dysplasia (HGD), and tumor present. Results: Of the 587 patients, 506 (86.2%), 17 (2.9%), 42 (7.2%), and 22 (3.7%) patients had clear margin, LGD, HGD, and tumor present at the margin, respectively. In the node-negative group, patients with clear margin (42.5%) had significantly lower 5-year cumulative overall recurrence rates compared with those with LGD (64.3%), HGD (74.4%), and tumor present status (100.0%). However, in the node-positive group, no significant differences were found in the 5-year cumulative recurrence rates among patients with clear margin (68.8%), HGD (91.1%), and tumor present status (75.0%). In addition, among the node-negative group with a non-clear margin, patients who received adjuvant radiotherapy showed significantly lower 5-year cumulative recurrence rates compared with those who did not receive adjuvant radiotherapy (69.5% versus 87.5%, P =0.037). Conclusions: Local treatment, including surgery and radiotherapy, may be crucial in node-negative patients but may have limited impact in node-positive patients. In node-positive patients, surgery without clinical deterioration, along with the timely initiation of adjuvant chemotherapy, may be crucial.