Objective:To investigate the surgical efficacy and prognosis influencing factors of hilar cholangiocarcinoma based on multidisciplinary diagnosis and treatment.Methods:The retrospective cohort study was conducted. The clinicopathological data of 91 patients with hilar cholangiocarcinoma who underwent surgery in Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School from April 2004 to April 2021 were collected. There were 59 males and 32 females, aged (61±10)years. Patients who were admitted from April 2004 to March 2014 underwent traditional surgical diagnosis and treatment, and patients who were admitted from April 2014 to April 2021 underwent multidisciplinary diagnosis and treatment. Observation indica-tors: (1) surgical situations; (2) postoperative situations; (3) postoperative pathological examina-tions; (4) postoperative prognosis analysis; (5) influencing factors of postoperative prognosis. Follow-up was conducted using telephone interview and outpatient examination. Patients were followed up once every 6 months after surgery to detect survival. The follow-up was up to April 2023. Measure-ment data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M(range), and comparison between groups was conducted using the Mann-Whitney U test. Comparison of ordinal data was conducted using the rank sum test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. The Kaplan-Meier method was used to draw survival curve and calculate survival rate. The Log-Rank test was used for survival analysis. Univariate and multivariate analyses were conducted using the COX proportional hazard model. Results:(1) Surgical situations. Of the 91 patients, there were 65 cases receiving hemi- or expanded hemi-hepatectomy, 13 cases receiving tri-hepatectomy, 9 cases receiving partial hepatectomy, 4 cases receiving extrahepatic bile duct resection. There were 24 cases receiving combined vein resection and reconstruction, 8 cases receiving combined pancreaticoduodenectomy, 6 cases receiving com-bined hepatic artery resection and reconstruction, including 24 cases receiving extended radical surgery (tri-hepatectomy, hepatic artery resection and reconstruction, hepatopancreaticoduodenec-tomy). The operation time, volume of intraoperative blood loss and intraoperative blood transfusion rate of 91 patients was (590±124)minutes, 800(range, 500?1 200)mL and 75.8%(69/91), respectively. Of the 91 patients, cases receiving extended radical surgery, the volume of intraoperative blood loss were 4, 650(range, 300?1 000)mL in the 31 patients who were admitted from April 2004 to March 2014, versus 20, 875 (range, 500?1 375)mL in the 60 patients who were admitted from April 2014 to April 2021, showing significant differences between them ( χ2=4.39, Z=0.31, P<0.05). (2) Post-operative situations. The postoperative duration of hospital stay and cases with postoperative infectious complications were (27±17)days and 50 in the 91 patients. Cases with abdominal infection, cases with infection of incision, cases with bacteremia and cases with pulmonary infection were 43, 7, 5, 8 in the 91 patients. One patient might have multiple infectious complications. Cases with bile leakage, cases with delayed gastric emptying, cases with chylous leakage, cases with liver failure, cases with pancreatic fistula, cases with intraperitoneal hemorrhage, cases with reoperation, cases dead during the postoperative 90 days were 30, 9, 9, 6, 5, 3, 6, 3 in the 91 patients. Cases with abdominal infection was 10 in the 31 patients who were admitted from April 2004 to March 2014, versus 33 in the 60 patients who were admitted from April 2014 to April 2021, showing a significant difference between them ( χ2=4.24, P<0.05). Cases dead during the postoperative 90 days was 3 in the 31 patients who were admitted from April 2004 to March 2014, versus 0 in the 60 patients who were admitted from April 2014 to April 2021, showing a significant difference between them ( P<0.05). (3) Post-operative pathological examinations. Of the 91 patients, cases with Bismuth type as type Ⅰ?Ⅱ, type Ⅲ, type Ⅳ, cases with T staging as Tis stage, T1 stage, T2a?2b stage, T3 stage, T4 stage, cases with N staging as N0 stage, N1 stage, N2 stage, cases with M staging as M0 stage, M1 stage, cases with TNM staging as 0 stage, Ⅰ stage, Ⅱ stage, Ⅲ stage, ⅣA stage, ⅣB stage, cases with R 0 radical resection, cases with R 1 or R 2 resection were 15, 46, 30, 1, 9, 25, 30, 26, 49, 36, 6, 85, 6, 1, 7, 13, 58, 6, 6, 63, 28. Cases with R 0 radical resection, cases with R 1 or R 2 resection were 15, 16 in the 31 patients who were admitted from April 2004 to March 2014, versus 48, 12 in the 60 patients who were admitted from April 2014 to April 2021, showing a significant difference between them ( χ2=9.59, P<0.05). (4) Postoperative prognosis analysis. Of the 91 patients, 3 cases who died within 90 days after surgery were excluded, and the 5-year overall survival rate and median overall survival time of the rest of 88 cases were 44.7% and 55 months. The 5-year overall survival rate was 33.5% in the 28 patients who were admitted from April 2004 to March 2014, versus 50.4% in the 60 patients who were admitted from April 2014 to April 2021, showing a significant difference between them ( χ2=5.31, P<0.05). Results of further analysis showed that the corresponding 5-year overall survival rate of cases without lymph node metastasis was 43.8% in the 16 patients who were admitted from April 2004 to March 2014, versus 61.6% in the 31 patients who were admitted from April 2014 to April 2021. There was a significant difference in the 5-year overall survival rate between these patients without lymph node metastasis ( χ2=3.98, P<0.05). The corresponding 5-year overall survival rate of cases with lymph node metastasis was 18.5% in the 12 patients who were admitted from April 2004 to March 2014, versus 37.7% in the 29 patients who were admitted from April 2014 to April 2021. There was no significant difference in the 5-year overall survival rate between these patients with lymph node metastasis ( χ2=2.25, P>0.05). (5) Influencing factors of postoperative prognosis. Results of multivariate analysis showed that poorly differentiated tumor and R 1 or R 2 resection were inde-pendent risk factors influencing prognosis after surgical treatment of hilar cholangiocarcinoma ( hazard ratio=2.62, 2.71, 95% confidence interval as 1.30?5.29, 1.30?5.69, P<0.05). Conclusions:Compared with traditional surgical diagnosis and treatment, treatment of hilar cholangiocarcinoma based on multidisciplinary diagnosis and treatment can expand surgical indications, reduce proportion of dead patients within 90 days after surgery, improve proportation of radical resection and long-term survival rate. Poorly differentiated tumor and R 1 or R 2 resection are independent risk factors influencing prognosis after surgical treatment of hilar cholangiocarcinoma.