Deep learning-assisted tumor radiomic dynamics on MRI predict pathological complete response in HCC undergoing immune-based therapy followed by hepatectomy

BACKGROUND AND AIMS: Pathological complete response (pCR) following conversion therapy for initially unresectable hepatocellular carcinoma (uHCC) remains challenging to predict preoperatively. This study developed and validated a model integrating clinicopathological and radiomic features of the tumor to predict pCR. METHODS: In this multicenter retrospective study, temporal radiomics features were extracted from baseline, post-treatment, and delta (change) MRIs. Serum AFP response was calculated as log₁₀(preoperative AFP)/log₁₀(baseline AFP). Univariate analysis, collinearity assessment, LASSO, and random forest were employed to perform feature selection. Fourteen machine learning models were benchmarked, with performance evaluated by using comprehensive metrics AUC, NPV, PPV, sensitivity, specificity, calibration, and decision curve analysis. RESULTS: The model was developed and validated in a training (n=78), an internal test (n=32), and an independent validation cohort (n=44). The delta radiomic model significantly outperformed both baseline (test AUC: 0.835 vs. 0.483, p <0.05; validation AUC: 0.783 vs. 0.434, p <0.05) and preoperative models (test AUC: 0.685, p <0.05; validation AUC: 0.506, p <0.05), demonstrating superior predictive performance and generalization capability in predicting lesion-level pCR. Notably, when predicting patient-level pCR, the radiomic model also showed robust discrimination, with AUCs of 0.819 in the test set and 0.781 in the validation set. The combined radiomics-AFP model achieved even higher AUCs of 0.920 (test) and 0.857 (validation) in predicting lesion-level pCR. CONCLUSIONS: Dynamic radiomic changes effectively predict pCR in uHCC after conversion therapy. Combining delta radiomics with AFP response significantly improves predictive performance, offering a non-invasive method for assessing pCR and potentially guiding personalized treatment decisions.