The role of liver transplantation for colorectal liver metastases: A systematic review and pooled analysis

Liver transplantation (LT) has gained interest in the treatment of unresectable colorectal liver metastases (CRLM) over the last two decades. Despite the initial poor outcomes, recent reports from countries with graft abundance have provided further insights in the potential of LT as a treatment for unresectable CRLM.A systematic literature search was conducted in the MEDLINE (PubMed), Embase, Scopus, Cochrane Library, Google Scholar, Virtual Health Library, Clinicaltrials.gov, and Web of Science databases (end-of-search date: January 27th, 2020) to identify relevant studies. Pooled overall and recurrence-free survival analysis at 6 months, 1, 2, 3, and 5 years was conducted with the Kaplan-Meier (Product Limit) method.Eighteen studies comprising 110 patients were included. The population consisted of 59.8% males with a mean age of 52.3 ± 9.3 years. CRLM diagnosis was synchronous in 83%, while 99% received chemotherapy, and 39% received liver resection prior to LT. The mean time from primary tumor resection to LT was 39.5 ± 32.5 months, the mean post-LT follow-up was 32.1 ± 22.2 months, and the mean time to recurrence was 15.0 ± 11.3 months. The pooled 6-month, 1-, 2-, 3-, and 5-year overall survival rates were 95.7% (95%CI: 89.1%-98.4%), 88.1% (95%CI: 79.6%-93.2%), 74.6% (95%CI: 64.2%-82.3%), 58.4% (95%CI: 47.2%-62.0%), and 50.5% (95%CI: 39.0%-61.0%), respectively. The pooled 6-months, 1-, 2-, 3-, and 5-year recurrence-free survival rates were 77.2% (95%CI: 67.2%-84.5%), 59.9% (95%CI: 49.0%-69.2%), 42.4% (95%CI: 31.8%-52.6%), 30.7% (95%CI: 20.9%-41.1%), and 25.6% (95%CI: 16.2%-36.0%), respectively.LT should be considered in patients with unresectable liver-only CRLM under strict selection criteria and only under well-designed research protocols. Ongoing studies are expected to further elucidate the indications and prognosis of patients undergoing LT for unresectable CRLM.