A Patient-Based Nomogram for Predicting Overall Survival after Radiofrequency Ablation for Hepatocellular Carcinoma

Abstract

Purpose: To develop a prognostic nomogram based on specific patient and tumor factors capable of estimating individual survival outcomes after radiofrequency (RF) ablation as a primary therapy for hepatocellular carcinoma (HCC). Materials and Methods: This retrospective study included 893 patients who were initially treated with curative RF ablation for HCC; patients were temporally divided into derivation (n = 607) and validation (n = 286) cohorts. A multivariate Cox proportional hazards model for overall survival was developed and validated. The discriminatory accuracy of the model was compared with the preexisting Cancer of the Liver Italian Program (CLIP) system and the Tokyo score previously proposed for percutaneous therapy for HCC by analyzing receiver operating characteristic (ROC) curves. Results: A nomogram was generated for 3-year survival, incorporating largest tumor diameter and number of tumors, serum albumin and creatinine, platelet count, prothrombin time, and serum a-fetoprotein on a logarithmic scale. It had good calibration and discrimination abilities with a C-index of 0.74. The validation results also showed that the nomogram performed well in terms of goodness-of-fit and discrimination (C-index, 0.72). Analysis of ROC curves in the validation cohort indicated that the model had better predictive power than CLIP and Tokyo scores (C-indexes, 0.54 and 0.66, respectively). Conclusions: This prognostic tool quantifying per-patient expected survival after RF ablation can be used in daily clinical decision making with regard to patients with HCC deemed suitable for radical ablation and is probably more reliable than existing guidelines.