BackgroundThe standard procedure for middle-third cholangiocarcinoma (MCC) is pancreaticoduodenectomy (PD); hepatopancreaticoduodenectomy (HPD) is often performed despite its high risk. There is no clear selection guidance for these procedures. MethodsPatients with MCC who underwent HPD or PD were retrospectively evaluated. The conventional PD was modified (mPD) to transect the bile duct beyond or close to the cranial level of the portal bifurcation. ResultsThe mPD group (n = 55) was characterized by older age, shorter operation time, less blood loss, and less frequent complications than were observed in the HPD group (n = 34). The median grossly tumor-free margin of the proximal bile duct (GM) was 13 mm vs 20 mm (P = 0.006). Overall survival did not differ significantly between groups (48% vs 53% at 5 years, P = 0.399). Multivariate analysis identified positive surgical margin as a sole independent prognostic factor (hazard ratio, 1.89; P = 0.043), which was statistically associated with GM length. Five-year survival for mPD patients with GM ≥15 mm was significantly better than that for those who had GM <15 mm (69% vs 33%, P = 0.011) and comparable to that of HPD patients (53%, P = 0.450). ConclusionThe mPD may be recommended in patients with MCC, provided that GM ≥15 mm is expected from the preoperative radiological imaging. Otherwise, HPD should be considered.