The definition and prognostic value of a wide resection margin remains controversial. The aim of this study was to assess the relevance of resection margin length for survival following intrahepatic cholangiocarcinoma (ICC) resection.

Patients scheduled for curative resection for ICC between 2015 and 2018 were identified from an institutional database. Demographic data, pathological margin length, and oncologic outcomes were collected and analyzed.

This study included 126 patients, of whom 78% underwent anatomical hepatectomy. The resection margin was <0.5, <1.0, and <1.5 cm in 73 (60%), 92 (73%), and 109 (87%) patients, respectively. A resection margin ≥1.0 cm was associated with favorable overall survival (OS) (HR: 0.403; 95% CI: 0.191–0.854; P = 0.018) and recurrence-free survival (RFS) (HR: 0.436; 95% CI: 0.232–0.817; P = 0.010). In the anatomical hepatectomy group, a resection margin ≥1.0 cm was an independent predictor of superior OS (HR: 0.451; 95% CI: 0.208–0.977; P = 0.043) and RFS (HR: 0.470; 95% CI: 0.242–0.914; P = 0.026).

A resection margin ≥1.0 cm was associated with significantly improved survival in ICC. Therefore, a clear margin of at least 1.0 cm should be achieved during ICC resection.