Clinical validity of Metroticket calculator in transplant patients undergoing prior chemoembolization for hepatocellular carcinoma

Aim To test the predictive performance of the Metroticket calculator for survival after liver transplantation (LT) of patients with hepatocellular carcinoma (HCC) undergoing prior transarterial chemoembolization (TACE). Methods A total of 142 patients treated with TACE and subsequent LT who had arterial enhancing HCC(s) were entered into this analysis. Tumor parameters measured by the enhancement radiological method pre-LT or by pathology post-LT were incorporated into the Metroticket analysis. The calculator was validated in terms of calibration and discrimination capacity. Results Mean 3- and 5-year survival rates predicted in the radiological model for all 142 patients were 76.4 and 70.1 %, respectively, lying comfortably within the 95 % confidence interval (CI) of the observed survival rate estimates (72.8–86.2 and 68.6–83.2 %, respectively). In the pathological model incorporating microvascular invasion, the mean anticipated survival rate at 5 years of 120 patients with viable nodules on explants was 69.5 %, also lying inside the 95 % CI of the actuarial rates (67.9–83.5 %). The c -indices as measures of discriminatory power were 0.61 and 0.62, respectively, for the 3- and 5-year predictions in the radiological model, and 0.72 for the 5-year prediction in the pathological model. The corresponding findings were similar for subgroups with hepatitis B virus infection and undergoing living-donor LT. Conclusions The Metroticket calculation based on explant data accurately predicts post-LT survival of HCC patients with prior TACE. Imaging estimate-based predictions before LT appear to provide poorer discrimination than calibration.