The true opportunity costs of offering liver transplantation to patients with colorectal liver metastases: A discrete event simulation analysis.

Abstract

Background: The standard treatment for patients with non-resectable colorectal cancer with liver-only metastasis (CRLM) in Norway, is palliative chemotherapy. The prognosis is bleak, with a 5-year overall survival of around 10%. During the last two decades, two Norwegian non-randomized pilot trials, SECA l and SECA ll, have examined liver transplantation as an alternative treatment option for CRLM patients. The SECA trials used different eligibility criteria; still, both trials provided favorable results, with a 5-year overall survival of 60% and 83%, respectively. Liver transplantation compared to palliative chemotherapy alone for CRLM patients has shown to be cost-effective in Norway. Despite this, liver transplantation has not been implemented as standard treatment for CRLM patients, primarily due to scarcity of donor livers. Insufficient liver availability is a worldwide issue, and patients throughout the world die every day as a consequence of staying endlessly on the waiting list. However, Norway is in a fortunate donor situation with a high liver availability, in which the median waiting time is around 35 days. Aim: This study was designed to identify the effect in waiting time and the opportunity cost, in terms of life years gained against life years lost, if extending the liver transplantation waiting list with 1 to 10 selected CRLM patients, based on the eligibility criteria from the SECA trials. Methods: A discrete event simulation (DES) model was designed to recreate the liver transplantation waiting list in Norway today. This model made it possible to capture the effect of change in waiting time and overall survival if allowing a number of selected CRLM patients on the waiting list. Results: The model results projected a marginal increase in overall waiting time of 14%-16% if two more CRLM patients were eligible for the liver transplantation waiting list. The break-even point, which was defined as life years gained equal to life years lost, was nine CRLM patients if using the eligibility criteria for the SECA l trial, while no break-even point was reached if using the eligibility criteria for the SECA ll trial. Conclusions: The true opportunity costs were projected to be positive if allowing selected CRLM patients eligible for the liver transplantation waiting list. However, SECA I and SECA II are two non-randomized pilot trials; hence, the outcome must be interpreted with caution.