Sex disparity in clinical characteristics and long-term prognosis after liver resection for patients with intrahepatic cholangiocarcinoma: A propensity score matching analysis

Aim To compare the survival outcomes between male and female patients with intrahepatic cholangiocarcinoma who underwent liver resection. Methods Data from 976 consecutive intrahepatic cholangiocarcinoma patients undergoing liver resection between January 2005 and May 2013 at the Eastern Hepatobiliary Surgery Hospital were prospectively collected and retrospectively reviewed. Patient clinicopathological characteristics, overall survival, and cumulative recurrence rates were compared between male and female patients using propensity score matching. Results Propensity score matching generated 313 matched pairs of patients. Among the entire cohort, the 1-, 3-, and 5-year overall survival and recurrence rates of the male and female patients were 60.2%, 37.3%, and 27.7% vs. 65.8%, 40.4%, and 31.0% (P=0.380) and 50.6%, 67.4%, and 74.2% vs. 44.4%, 63.5%, and 69.6% (P = 0.123), respectively. In the matched cohort, the 1-, 3-, and 5-year overall survival and recurrence rates of the male and female patients were 60.6%, 35.9% and 22.4% vs. 66.4%, 40.6% and 31.1% (P=0.041) and 51.5%, 69.3% and 83.9% vs. 44.3%, 63.6%, and 69.9% (P=0.041), respectively. After adjustment for other confounding variables by multivariate Cox regression analysis, male sex was independently associated with worse overall survival (hazard ratio=1.322, 95% confidence interval: 1.079-1.621, P=0.007) and tumor recurrence (hazard ratio=1.337, 95% confidence interval: 1.088-1.645, P=0.006). A subgroup analysis of patients younger than 55 years old after propensity score matching showed that male patients had significantly worse overall survival and higher recurrence rates than female patients after surgery, while no significant difference in long-term overall survival and recurrence was observed between male and female patients older than 55 years old after propensity score matching. Conclusion Male sex was an independent risk factor for overall survival and tumor recurrence in patients after liver resection for intrahepatic cholangiocarcinoma.