The prognostic value of 18F–FDG PET/CT prior to liver transplantation for nonresectable colorectal liver metastases

Abstract

The main objective of this study was to evaluate the prognostic value of volumetric and metabolic information derivied from F-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) in combination with computed tomography (CT) prior to liver transplantation (LT) in patients with nonresectable colorectal liver metastases (CLM). Due to scarcity of liver grafts, prognostic information enabling selection of candidates who will gain the highest survival after LT is of vital importance. 18F-FDG PET/CT was a part of the preoperative study protocol. Patients without evidence of extrahepatic malignant disease on 18F-FDG PET/CT who also fulfilled all the other inclusion criteria underwent LT. The preoperative 18F-FDG PET/CT examinations of all patients included in the SECA (secondary cancer) study were retrospectively assessed. Maximum, mean and peak standardized uptake values (SUVmax, SUVmean and SUVpeak), tumor to background (T/B) ratio, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured and calculated for all liver metastases. Total MTV and TLG were calculated for each patient. Cut-off values were determined for each of these parameters by using receiver operating characteristic (ROC) analysis dividing the patients into two groups. One, three and five-year overall survival (OS) and disease free survival (DFS) for patients over and under the cut-off value were compared by using the Kaplan-Meier method and log rank test. Twenty-three patients underwent LT in the SECA study. Total MTV and TLG under the cut-off values were significantly correlated to improved OS at three and five years (p=0.027 and 0.026) and DFS (p=0.01). One, three and five-year OS and DFS were not significantly related to SUVmax, SUVmean, SUVpeak or T/B-ratio. Total MTV and TLG from 18F FDG PET/CT prior to LT for nonresectable CLM were significantly correlated to improved three and five-year OS and DFS and can potentially improve the patient selection for LT.