Surgeons should consider the margin-to-size ratio (MSR) as a key factor for patient outcomes in resectable intrahepatic cholangiocarcinoma (ICC).

• Higher MSR significantly improves recurrence-free survival (RFS), with an HR of 0.59.
• An MSR threshold of 0.142 predicts better 3-year RFS: 55.7% for high MSR vs. 45.2% for low MSR.

This approach may help tailor surgical margins based on individual tumor characteristics, enhancing patient outcomes.