Risk Model for Predicting Aggressive Recurrence of Hepatocellular Carcinoma after Microwave Ablation Using MRI and Clinical Parameters.

Purpose To develop and validate a risk score model for predicting aggressive recurrence (AR) of hepatocellular carcinoma (HCC) after microwave ablation (MWA). Materials and Methods This retrospective study included consecutive patients with solitary HCC (≤3 cm) who underwent preoperative contrast-enhanced MRI and MWA from June 2014 to October 2019. In the training set, multivariable Cox regression analysis identified clinical, laboratory, and MWA parameters and MRI features associated with AR. The resulting predictive model, named Aggressive Recurrence after Microwave Ablation (ARMA), was evaluated in the test set using the concordance index (C-index) and compared with the Barcelona Clinic Liver Cancer staging system and known risk factors. Kaplan-Meier survival curves were compared using the log-rank test. Results A total of 393 eligible patients (mean age, 57.7 years ± 11.2 [SD]; 299 [76.1%] male) were included. AR occurred in 79 of 275 (28.7%) patients in the training set and 37 of 118 (31.4%) patients in the test set. Independent predictors of AR-free survival (ARFS) were periportal location (hazard ratio [HR], 1.72; < .001), ablation duration (HR, 1.00; = .02), and arterial phase hyperenhancement proportion (APHE) at MRI (HR, 1.77; = .002). The ARMA model showed better predictive performance for ARFS compared with other staging systems and known risk factors (C-indexes, 0.72 vs 0.58-0.63; value range, <.001-.003). High-risk patients (ARMA score ≥ 0.700) showed worse ARFS ( < .001) and recurrence-free survival ( = .002) than low-risk patients (ARMA score < 0.700). Conclusion The ARMA score, integrating periportal location, ablation duration, and APHE, predicted ARFS and identified patients at high risk for AR. Model Training, Model Validation, Ablation Techniques, Liver, Outcomes Analysis, Aggressive Recurrrence, Microwave Ablation, Periportal Hepatocellular, Carcinoma, Arterial Phase Hyperenhancement Proportion, Ablation Duration © RSNA, 2026.