Living-donor liver transplantation for non-resectable colorectal liver metastases: protocol for a multicentric, single-arm study.

Introduction: The only treatment for non-resectable colorectal liver metastasis (CRLM) is medical therapy, and the overall survival (OS) rate at 3 and 5 years is approximately 30%-40% and less than 10%, respectively. In 2020, a group in Norway reported that liver transplantation for non-resectable CRLM improved the 5-year OS rate to up to 83%. Clinical trials have been launched since that report was published, but most have involved deceased-donor liver transplantation rather than living-donor liver transplantation. Our study will assess the efficacy and safety of living-donor liver transplantation for patients with non-resectable CRLM.

Methods And Analysis: This is an investigator-driven, multicentre, prospective, single-arm study involving 11 university hospitals in Japan. Patients with non-resectable CRLM and resected primary cancers will be enrolled in the study. Any patients with histopathological or genetic mutations, such as those of RAS and BRAF, are eligible. Furthermore, patients who underwent lung treatment for three or fewer pulmonary metastases and experienced no recurrence for more than 6 months are eligible. The eligibility of the candidates will be reviewed by the Central Eligibility Review Committee. The primary endpoint is the 3-year OS rate. Assuming an OS rate of 70% and a threshold of 45%, the number of required patients is 23, with an alpha error of 5% (one-sided), power of 80% and a 10% dropout rate.

Ethics And Dissemination: Ethical approval was obtained from the ethical review board of Kyoto University (R-1591). All participants are required to provide written informed consent. The results will be submitted for publication in a peer-reviewed journal.

Trial Registration Number: jRCT1050230053 and UMIN000049785.