Is recurrence rate of incidental hepatocellular carcinoma after liver transplantation similar to previously known HCC? Towards a predictive recurrence score

Background. Incidental hepatocellular carcinoma (iHCC) generates uncertainty over risk of recurrence after liver transplantation (LT). Aim. To compare recurrence between iHCC and confirmed HCC diagnosed prior to transplant based on imaging criteria (cHCC). Material and methods. Fifty-four HCC patients were analyzed from a series of 309 consecutive adult transplanted patients. We developed a recurrence predicting score (RPS) applying ORs based on pathologic risk variables. Results. Incidence of iHCC was 4.8% (n = 15) and overall recurrence 12.9% (cHCC 15.4% and iHCC 7%; P = 0.39). Variables included in the RPS were: microvascular invasion OR 17.8 (1.78-178.97; P = 0.014: 2 points), neural invasion OR 15.5 (1.13-212.17; P = 0.04: 1.5 points), nuclear grade > II OR 9.3 (1.17-74.84; P = 0.035: 1 point), and beyond Up-to 7 criteria OR 13.1 (1.66-103.67; P = 0.015: 1.5 points). Two risk groups were identified: low risk for recurrence (0-1 point) and intermediate-high risk groups (2-6 points). Low risk category remained an independent predictor of recurrence: OR 0.11 (0.01-0.67; P = 0.017); AUROC of 0.75 (0.54-0.96). A tendency towards more patients categorized as low risk group among iHCC patients was observed (69.2%; P = 0.13). Conclusions. In this series iHCC was not associated to lower risk of recurrence when compared to cHCC. We propose application of an RPS as a clinical tool for recurrence risk estimation.