Clinical implications and biological features of a novel postoperative recurrent HCC classification: A multi-centre study.

BACKGROUND & AIMS: The multiplicity of hepatocellular carcinoma (HCC) recurrence patterns is the most important determinant of patients' postsurgical survival. A systematic HCC recurrence classification is needed to help prevent and treat postoperative HCC recurrence in the era of precision medicine. METHODS: A total of 1319 patients with recurrent HCC from four hospitals were enrolled and divided into a development cohort (n = 916), internal validation cohort (n = 225) and external validation cohort (n = 178). A comprehensive study of patients' clinicopathological factors and biological features was conducted. RESULTS: Four subtypes of recurrence were identified, which integrated recurrence features, survival, effects on systemic and liver function and potential therapeutics after recurrence: type I (solitary-intrahepatic oligorecurrence); type II (multi-intrahepatic oligorecurrence); type III (progression recurrence) and type IV (hyper-progression recurrence). Type III~IV recurrence indicated exceptionally poor prognosis. Subsequently, two nomogram models were established for type III~IV recurrence prediction, and both demonstrated excellent predictive performance and applicability of pre and postoperative strategy formulation. Multiple biological analyses revealed that HCC cases with type III~IV recurrence were characterized by enrichment in p53 mutations, CCND1 amplification, high proliferation/metastasis potential, inactive metabolism and immune exhaustion features. Over-expression of high mobility group protein 2 (HMGA2) enhanced the highly malignant behaviour of HCC through multiple molecular pathways, making it a potential prognostic predictor and therapeutic target. CONCLUSIONS: This 'recurrent HCC classification' has important potential value in identifying patients with surgical benefit, predicting postsurgical survival and guiding treatment strategies. Multidimensional biological insights also increased knowledge of factors associated with HCC recurrence.