Long-term outcome and prognostic nomogram for intrahepatic cholangiocarcinoma after thermal ablation: a retrospective study

Background: To evaluate the efficacy of thermal ablation and transcatheter arterial chemoembolization (TACE) in treating intrahepatic cholangiocarcinoma (ICC), and to propose a prognostic nomogram to predict overall survival (OS) after ablation. Methods: ICC patients (n=58) undergoing percutaneous CT-guided ablation with or without pre-ablation TACE at our institute from 2009 to 2013 were enrolled in the primary cohort. All treatments were performed under conscious sedation and local anesthesia. Prognostic factors for OS were identified to establish the nomogram. The nomogram was accessed by the concordance index (C-index) and calibration curve, and compared with 11 currently available prognostic systems. The nomogram was further evaluated in a validation cohort (n=19) of patients with ICC who underwent thermal ablation and TACE from 2014 to 2016. Results: In the primary cohort, the median OS was 17.9 months and the 1-, 3-, 5-year OS rates were 69.6%, 29.5%, 23.6%, respectively. Three single independent predictors (number of tumors, vascular invasion and lymph node metastasis) for OS were identified by multivariate analysis and used to formulate the nomogram. The C-index of the nomogram was 0.834 [95% confidence interval (CI), 0.765 to 0.904], significantly higher than that of ten current prognostic systems for ICC, and similar with that of the Wang nomogram. The performance of the proposed nomogram was also confirmed in the validation cohort (C-index, 0.839). Conclusions: Thermal ablation appears to be effective for ICC patients. The proposed nomogram is helpful for predicting patient survival after ablation treatment.