Assessing Early HCC Recurrence After Liver Transplantation: The Predictive Value of 18F-FDG PET/CT and Microvascular invasion

Background and Aims

Liver transplantation (LT) is the most effective treatment against hepatocellular carcinoma, but recurrence remains challenging. Traditional criteria based on tumor size, nodule number and AFP levels have limited success in predicting aggressiveness. 18F-FDG PET/CT has shown promise in identifying high-risk tumor features, including microvascular invasion (MVI), a key predictor of recurrence.

Methods

In this retrospective, single-center study, all consecutive patients who underwent LT for HCC between 2010 and 2019 were included. During pre-LT work-up all patients underwent 18F-FDG PET/CT and, following the LT, explant pathology was analyzed for MVI and other histological features. The primary endpoint was to identify predictors of early HCC recurrence (within 24 months after LT). Secondary endpoints included identifying predictors of high-risk histological features at explant, describing recurrence patterns, and assessing post-recurrence survival.

Results

The study included 143 patients (median age 59 years [IQR 54-64], 85% males, median MELD 10 [IQR 8-14], median AFP value 8.5 [IQR 4-39] ng/ml. Forty (28%) HCC resulted 18F-FDG PET/CT positive and 25 (17%) developed HCC recurrence post-LT (median post-LT follow-up 49 months [IQR 28.5-77]), with 12 (48%) experiencing early recurrence. MVI at explant was independently associated with early recurrence (HR: 7.20, 95% CI 1.82-28.45, p=0.005), while intra-hepatic 18F-FDG PET/CT positivity within six months before LT independently predicted MVI at explant (OR 3.90, 95% CI 1.30–11.71, p=0.01).

Conclusions

18F-FDG PET/CT is a valuable tool for pretransplant risk assessment, predicting MVI, and indirectly predicting early recurrence. Its incorporation into the selection criteria for LT may enhance patient stratification and post-transplant outcomes.