Limited tumour progression beyond Milan criteria while on the waiting list does not result in unacceptable impairment of survival

Abstract

Background & aims: Defining optimum management of patients progressing beyond Milan criteria on the waiting list is a controversial topic. Our aim was to determine whether the policy of allowing a limited progression beyond enlistment criteria permits acceptable post-transplant outcomes in terms of survival and recurrence.

Methods: Patients with hepatocellular carcinoma included on the waiting list for orthotopic liver transplantation (OLT) between January 1989 and December 2016 were analysed. Tumour features were assessed at inclusion on the waiting list, before OLT and at explant pathology. Patients were retained on the waiting list despite exceeding enlistment criteria if not presenting with macrovascular invasion, extrahepatic spread or cancer-related symptoms.

Results: A total of 495 patients constituted the target population. Comparison between the Milan-in (n = 434) and Milan-out (n = 61) groups showed statistically significant differences in: largest tumour size; BCLC stage; patients treated before OLT; alpha-fetoprotein, and time on the waiting list. Milan-out patients showed a significantly higher number of poorly differentiated nodules, satellitosis and microscopic vascular invasion. The 1-, 3-, 5- and 10-year survival rate was 89.6%, 82.5%, 75%, and 55.5%, vs. 83.6%, 70.5%, 65.5%, and 53.9% for Milan-in/Milan-out patients, respectively. Recurrence rates at 1, 3, 5 and 10 years were 1.2%, 3.3%, 5.5%, and 10.8% vs. 7.1% 14.5%, 23%, and 23% for Milan-in and Milan-out patients, respectively (p <0.01).

Conclusion: This study shows that although limited tumour progression without reaching major adverse predictors (vascular invasion, extrahepatic spread, cancer symptoms) has an expected impact on recurrence rate, overall survival remains above the minimum proposed benchmark of 65% at 5 years. The clinically relevant increase in tumour recurrence must be considered when analysing the benefit of this approach in the face of limited organ supply.

Lay summary: When considering orthotopic liver transplantation for patients with hepatocellular carcinoma, optimum results are achieved when transplanting patients within the Milan criteria. However, the most appropriate strategy for patients who progress beyond these criteria while on the waiting list is still unclear. Herein, we show that transplantation is associated with acceptable overall survival in select patients who progress beyond the Milan criteria, although recurrence rates were notably higher. Therefore, the assessment of transplantation viability in these patients must consider the availability of organs and the impact on other patient categories.

Keywords: Hepatocellular carcinoma; Liver transplant; Milan criteria; Tumour progression; Waiting list.