Objective To investigate the clinical application value of extended radical resec-tion for perihilar cholangiocarcinoma (PHCC).

Methods The retrospective cohort study was conducted. The clinicopathological data of 91 patients with PHCC who were admitted to Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School from April to December 2024 were collected. There were 62 males and 29 females, aged 65(range, 41-80) years. Among the 91 patients, 61 cases undergoing conventional radical resection for PHCC were allocated into conventional resection group and 30 cases undergoing extended radical resection were allocated into extended resection group. Observation indicators: (1) surgical outcomes; (2) postoperative situations; (3) follow‑up; (4) influencing factors analysis of postoperative survival of PHCC patients under-going radical resection. Comparison of measurement data with normal distribution between groups was conducted using the independent sample t test. Comparison of measurement data with skewed distribution between groups was conducted using the Mann-Whitney U test. Comparison of count data between groups was conducted the chi‑square test or Fisher exact probability. Comparison of ordinal data between groups was conducted using the Mann‑Whitney U test. The Kaplan‑Meier method was used to calculate survival rates and plot survival curves, and survival rates were compared using the Log‑rank test. Univariate analysis was conducted using the Cox proportional hazards model. Variables with P<0.05 in univariate analysis and clinically relevant indicators were included in Cox proportional hazards model for multivariate analysis. A multivariate Logistic regression model was used to adjust for unbalanced clinicopathological factors to evaluate the independent association between surgical procedures and postoperative complications.

Results (1) Surgical outcomes: there were significant differences between the two groups in operation time, volume of intraoperative blood loss, hilar occlusion, trisectionectomy, hepatic artery resection and reconstruction, portal vein resection and reconstruction, combined pancreaticoduodenectomy, and bile duct plasty (t=-2.95, Z=-2.03, χ²=4.79, 39.47, 17.08, 7.22, 17.08, 4.04, P<0.05). (2) Postoperative situations: there were significant differences between the two groups in intra‑abdominal infection, severe postoperative complications, and postoperative hospital stay (χ²=11.34, 6.11, Z=-3.11, P<0.05). The difference in pancreatic fistula was also significant between the two groups (P<0.05). Multivariable-adjusted binary Logistic regression analysis was performed using intra‑abdominal infection and severe postoperative complications as dependent variables, and surgical approach (extended radical resection versus standard radical resection), preoperative intrahepatic portal vein branch embolization, portal vein invasion, hepatic artery invasion, TNM stage, and T stage as independent variables. The results showed that extended radical resection was an independent risk factor for intra-abdominal infection and severe postoperative complications (hazard ratio=7.55, 4.20, 95% confidence interval as 2.05-27.81, 1.26-13.88, P<0.05). (3) Follow‑up: of 91 patients, 87 cases were successfully followed up for 44(range, 5-125) months. The 5‑year survival rate was 51.8%, with a median survival time of 66(range, 5-125) months. The 5‑year survival rate was 52.1% and median survival time was 66(range, 6-124) months for the conventional resection group, versus 50.8% and 69(range, 5-125)months for the extended resection group, showing no significant difference in survival between the two groups (χ²=0.77, P>0.05). (4) Influencing factors analysis of postoperative survival of PHCC patients undergoing radical resection: results of multivariate analysis indicated that microvascular invasion was an independent influencing factor for postoperative survival in patients undergoing radical resection for PHCC (hazard ratio=2.52, 95% confidence interval as 1.16-5.42, P<0.05).

Conclusions Compared with conventional radical resection for PHCC, extended radical resection is associated with longer operation time and postoperative hospital stay, increased intraoperative blood loss, higher risks of intra‑abdominal infection, pancreatic fistula, and severe postoperative complications. There is no significant difference in the death in hospital and 5‑year survival between the two groups. Microvascular invasion is an independent influencing factor for postoperative survival in patients undergoing radical resection for PHCC.