Table 1_Preoperative MRI features and clinical factors for predicting early recurrence of hepatocellular carcinoma after hepatectomy.docx

Overall, 183 patients (57.2%) experienced early recurrence. The final combined Cox model retained log(PIVKA-II), tumor size >5 cm, satellite nodule, peritumoral hypointensity on portal venous phase images, intrahepatic vessel invasion, and incomplete capsule. In the development cohort, the apparent C-index was 0.756, and the bootstrap-corrected 24-month AUC was 0.829.

In the external validation cohort, the C-index was 0.892, the 24-month AUC was 0.978, and the Brier score was 0.087. Calibration analysis indicated imperfect absolute risk calibration, with a calibration slope of 2.705 and an intercept of -1.288; grouped calibration suggested risk overestimation in the lower predicted-risk range. The development cohort-derived cutoff of 0.584 separated patients with different early recurrence risks in both cohorts.

In the external validation cohort, only one early recurrence event occurred in the low-risk reference group, so the risk-stratification HR should be interpreted as directional separation rather than as a stable clinical effect-size estimate.</p>Conclusion<p>This preoperative MRI-clinical Cox model showed good predictive performance for early recurrence after hepatectomy for HCC and high discrimination in external validation.

Its calibration and clinical utility require further evaluation in larger prospective multicenter cohorts.</p>