Development of a new model for predicting recurrence after liver transplantation for hepatocellular carcinoma beyond Milan criteria

ObjectiveTo develop a new model for predicting recurrence after liver transplantation for hepatocellular carcinoma (HCC) beyond Milan criteria based on related preoperative and postoperative indicators. MethodsA retrospective analysis was performed for the clinical data of the patients with HCC beyond Milan criteria who underwent orthotopic liver transplantation for the first time in Tianjin First Central Hospital from August 2014 to July 2018, and according to the presence or absence of recurrence during follow-up, the patients were divided into recurrence group and no-recurrence group. The t-test or the Mann-Whitney U test was used for comparison of continuous data between groups, and the chi-square test or the Fisher’s exact test was used for comparison of categorical data between groups. The Kaplan-Meier method was used to plot survival curves, and the log-rank test was used for comparison of survival curves. Univariate and multivariate Cox proportional hazards regression analyses were used to identify the risk factors for recurrence-free survival after surgery. A new model was developed for recurrence after liver transplantation in the patients with HCC beyond Milan criteria based on the risk factors identified. The area under the receiver operating characteristic curve (AUC) was used to evaluate predictive performance, and the Hosmer-Lemeshow test was used to assess the goodness of fit of the model. ResultsA total of 117 patients with HCC beyond Milan criteria were enrolled in this study, with a median follow-up time of 24 (1-74) months. A total of 53 patients (45.3%) experienced recurrence after surgery, among whom 52 (98.1%) had recurrence within 3 years after surgery, with a median time to recurrence of 6 (1-52) months. The Cox proportional hazards regression analysis showed that preoperative serum alpha-fetoprotein (AFP) ＞769 ng/mL, neutrophil-lymphocyte ratio (NLR) ＞3.75, and ki67 index ＞0.25 were independent risk factors for recurrence-free survival after liver transplantation. The model established based on these three risk factors had an AUC of 0.843, with good sensitivity (88.7%) and specificity (70.3%). The optimal cut-off value was selected according to the maximization of Youden index, and then the patients were divided into low-risk group (0-1 point) and high-risk group (1.5-4 points). The log-rank test showed that the low-risk group had significantly higher 3-and 5-year recurrence-free survival rates than the high-risk group (84.1%/72.0% vs 10.9%/10.9%, χ2=29.425, P＜0.001). ConclusionLiver transplantation for HCC beyond Milan criteria should be performed with caution, and the predictive model established based on preoperative AFP, NLR, and ki67 index can accurately assess the indication for liver transplantation in such patients.