LIVER TRANSPLANTATION VERSUS ALPPS FOR COLORECTAL LIVER METASTASES: AN ENTROPY BALANCED RETROSPECTIVE ANALYSIS

Objective: The primary endpoint of this study was to compare liver transplantation (LT) with Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) in the treatment of colorectal liver metastases (CRLM). Summary Background Data: ALPPS is usually performed for borderline CRLM cases and published oncological outcomes appear to be inferior to those obtained after LT. Methods: All consecutive patients undergoing ALPPS for CRLM across 14 centers between September 2012 and September 2022 were considered. The selected ALPPS patients were compared with patients receiving LT from November 2006 to June 2019 performed at a single institution. Entropy balancing was applied to eliminate all confounding bias simulating what would have happened if ALPPS patients had been transplanted. Results: During the study period, 121 consecutive patients were submitted to ALPPS and 46 were enrolled by fulfilling the inclusion criteria. These 46 cases were compared with 54 patients submitted to LT. Median OS after ALPPS was 76 months (95% CI 28.9-123) compared to 72.7 months in patients who underwent LT (95% CI 43.4-102 months). After reweighting, the risk of death related to ALPPS was higher when compared to LT (HR=1.40, 95%CI 0.63-3.09) but no significant differences were found between the 2 groups (p=0.398). When splitting the ALPPS cohort into completed and failed procedures, the median OS in failed ALPPS (31.1 months, 95% CI 0-73.3 months) was significantly lower than that of patients submitted to LT (p=0.043). When ALPPS patients were further selected based on SECA-II criteria, the median OS was significantly (p=0.022) higher in the LT group (not reached) compared to ALPPS (76 months, 95% CI 21-130 months). Conclusions: LT without current stringent selection criteria did not provide a significant survival benefit compared to ALPPS. The final choice between these two strategies seems to depend solely on the possibility of completing stage 2 and whether the patient meets the most updated transplant criteria.