[A new classification of intrahepatic cholangiocarcinoma based on actual anatomy:a series of 135 cases]

Objective: To explore the feasibility and clinical value of a new classification for resectable intrahepatic cholangiocarcinoma (IHCC) according to the actual anatomy. Methods: The data of 135 patients with IHCC who were admitted to the Department of Hepatopancreatobiliary Surgery,Second Affiliated Hospital of Zhejiang University School of Medicine from November 2011 to November 2020 after discussion by a multidisciplinary team and planned to undergo radical resection were analyzed retrospectively. There were 77 males and 58 females,with a median age of 61 years (range:26 to 86 years),of which 38 cases had vascular invasion. This new classification was carried out independently by two hepatobiliary surgeons. First,a preliminary classification was made based on the location of the tumor,and then the final classification was based on vascular invasion. All patients were followed up by telephone,and the follow-up was as of November 2020. Survival time is defined as the time after surgery to follow-up or death. Log-rank test was used to compare patients' median recurrence-free survival and overall survival time. The Cox proportional hazard model was used to analyze the prognosis factors of the overall survival time of patients with IHCC. Results: Among the 135 patients,129 underwent R0 resection and 6 underwent R1 resection. According to the actual anatomy,28 cases (20.7%) belonged to segmental type, 43 cases (31.9%) belonged to branch type, 64 cases (47.4%). The median survival time of all patients was 35.2 months(95%CI:21.3 to 70.5 months),the 1-year cumulative survival rate was 75.1%,the 3-year cumulative survival rate was 45.8%,and the 5-year cumulative survival rate was 39.0%. After grouping according to the classification,the median survival time of segmental patients was 36.9 months (more than 50% of patients reached the median survival time),and the median survival time of branched patients was 33.8 months (95%CI:16.8 to 38.5);The median survival time of lobe patients was 25.0 months (95%CI:13.6 to 58.7). The result of Log-rank test between groups indicated that the median survival time of patients with segmental type was better than that of patients with branch and lobe type(HR=2.03,95%CI:1.24 to 3.64,P=0.006);There was no significant difference in survival time between patients with branch type and lobe type (P=0.685). The results of the multivariate analysis of the Cox risk ratio model suggested that the actual anatomical location classification (HR=2.32,95%CI:1.10 to 4.92,P=0.028) and the postoperative lymph node metastasis rate (HR=2.06,95%CI:1.24 to 3.45,P=0.005) were independent factors related to survival after radical resection of IHCC patients. Conclusion: It is simple and convenient to classify resectable IHCC by actual anatomy,which can be used to preliminarily judge the prognosis of patients and provide a feasible classification scheme for the clinic.