Pre-transplant metabolic tumor volume predicts recurrence following liver transplantation for colorectal metastasis: A multicenter study.

Abstract

Liver transplant (LT) for colorectal cancer liver metastases (CRLM) is increasingly popular, yet the ideal selection criteria remain unknown. Pre-transplant PET metabolic tumor volume (MTV) has been described as predicting recurrence, with a proposed cut-off of MTV ≥70cm3. This approach has not been validated. Patients undergoing LT for CRLM at two academic transplant centers (1/1/2017-12/1/2023) were included. PET-MTV was calculated by a staff radiologist from the most recent PET-scan before LT using the published protocol. Twenty-six patients were included. Median follow-up was 609 days (IQR 320-1069) and from PET to LT was 1.9 months (1.3-2.6). Nearly all (n=24, 92.3%) received living donor transplantation. Absolute recurrence rate was 30.8% (n=8). Actuarial unadjusted 1-, and 2-year RFS were 83% (n=15/18), and 62% (n=8/13); 1- and 2-year OS were 100% (n=18/18), and 85% (n=11/13).The incidence of recurrence-per-year follow-up was 0.35 when MTV ≥70cm3 versus 0.10 if MTV <70cm3 (P<0.001). Median RFS using Kaplan-Meier product-estimate was 0.83 years (95%CI 0.43-1.23) in MTV≥70cm3 versus 4.1 years (95%CI 2.90-5.22) when MTV<70cm3 (P<0.001); this was also associated with improved OS (P=0.003). MTV>70cm3 demonstrated HR=2.42 (95%CI 2.2-62.2, P=0.006) for association with RFS on univariate Cox-proportional hazards analysis, and an Area-Under-the-Curve (AUC)=0.771 (95%CI 0.560-0.981) for predicting recurrence (P=0.030)Nineteen patients (69.2%) had histologically viable tumor, which was associated with recurrence (43% vs. 0%, P=0.039) and reduced RFS (log-rank P=0.019). PET-MTV was associated with presence of histologically-viable tumor (AUC=0.763, 95%CI 0.583-0.944). PET-MTV ≥70cm3 was associated with reduced RFS and OS after LT for CRLM, confirming findings from the Norway group. This is likely due to its' ability to identify residual viable tumors, which are independently associated with recurrence. PET-MTV should be a key selection criterion prior to LT for CRLM.