An MRI‐Based Prognostic Stratification System for Medical Decision‐Making of Multinodular Hepatocellular Carcinoma Patients Beyond the Milan Criteria

Abstract

BackgroundThe suitability of hepatectomy among patients with multinodular hepatocellular carcinoma (MHCC) beyond the Milan criteria remains controversial. There is a need for a reliable risk stratification tool among these patients for the selection of ideal candidates of curative resection.PurposeTo determine the clinicoradiological prognostic factors for patients with MHCC beyond the Milan criteria to further develop a stratification system.Study TypeRetrospective.Subjects176 patients with pathologically confirmed MHCC beyond the Milan criteria.Field Strength/SequenceThe 1.5 T scanner, including T1‐, T2‐, diffusion‐weighted imaging, in/out‐phase imaging, and dynamic contrast‐enhanced imaging.AssessmentConventional MRI features and preoperative laboratory data including aspartate aminotransferase (AST) and α‐fetoprotein (AFP) were collected and analyzed. Two nomograms incorporating clinicoradiological variables were independently constructed to predict recurrence‐free survival (RFS) and overall survival (OS) with Cox regression analyses and verified with 5‐fold cross validation. Based on the nomograms, two prognostic stratification systems for RFS and OS were further developed.Statistical TestsThe Cohen's kappa/intraclass correlation coefficient, C‐index, calibration curve, Kaplan–Meier curve, log‐rank test. A P value <0.05 was considered statistically significant.ResultsAST > 40 U/L, increased tumor burden score, radiological liver cirrhosis and nonsmooth tumor margin were independent predictors for poor RFS, while AST > 40 U/L, AFP > 400 ng/mL and radiological liver cirrhosis were independent predictors for poor OS. The two nomograms demonstrated good discrimination performance with C‐index of 0.653 (95% confidence interval [CI], 0.602–0.794) and 0.685 (95% CI, 0.623–0.747) for RFS and OS, respectively. The 5‐fold cross validation further validated the discrimination capability of the nomograms. Based on the nomogram models, MHCC patients beyond the Milan criteria were stratified into low−/medium−/high‐risk groups with significantly different RFS and OS.Data ConclusionThe proposed MRI‐based prognostic stratification system facilitates the refinement and further subclassification of patients with MHCC beyond the Milan criteria.Evidence Level4.Technical Efficacy2.