Risk stratification system to predict recurrence of intrahepatic cholangiocarcinoma after hepatic resection

Background: Previous nomograms for intrahepatic cholangiocarcinoma (ICC) were conducted to predict overall survival, which could be influenced by various factors. Herein, we conducted our nomogram to predict recurrence of the tumor only after hepatic resection. Methods: The nomogram was established with prognostic factors for the relapse-free survival (RFS) analyzed from our single center cohort and was evaluated by comparing with the American Joint Committee on Cancer (AJCC) staging system for the predictive accuracy. Results: Seropositivity of hepatitis B surface antigen (hazard ratio [HR], 0.505; 95% confidence interval [CI], 0.279 to 0.914; P = 0.024), tumor size of larger than 5 cm (HR, 1.947; 95% CI, 1.177 to 3.219; P = 0.009), Child-Pugh score of B (HR, 3.067; 95% CI, 1.293 to 7.275; P = 0.011), and lymph node metastasis (HR, 2.790; 95% CI, 1.628 to 4.781; P < 0.001) were found to be independent prognostic factors that significantly affected RFS. The calibration curve for the prediction revealed excellent agreement between estimation by our stratification system and actual RFS. The concordance C index of the nomogram (0.71; 95% CI, 0.65 to 0.77) revealed to be significantly higher than the AJCC staging system (0.66; 95% CI, 0.60 to 0.72). In the validation cohort, our risk stratification system (C-index 0.65; 95% CI, 0.59 to 0.71) also revealed more precise prediction than the AJCC staging system (C-index, 0.57; 95% CI, 0.50 to 0.64). Conclusions: Our nomogram could more accurately predict recurrence of ICC after hepatic resection than the AJCC staging system.