The Role of PIVKA-II as a Predictor of Early Hepatocellular Carcinoma Recurrence-Free Survival after Liver Transplantation in a Low Alpha-Fetoprotein Population

Simple Summary Although the RETREAT score improves hepatocellular carcinoma (HCC) recurrence prediction post liver transplantation (LT), there is a necessity for more discriminating models in low alpha-fetoprotein (AFP) populations. Investigating the use of a protein induced by vitamin K deficiency or antagonist-II (PIVKA-II) as a predictor after liver transplantation, this study shows that patients with low PIVKA-II in combination with low AFP or low PIVKA-II within the Milan criteria have 100% recurrence-free survival. This suggests that these groups might not need HCC surveillance after LT. PIVKA-II might outperform AFP in predicting microvascular invasion on explant and could assist in identifying LT candidates with the highest risk of HCC recurrence in future models.Abstract Introduction: AFP and the RETREAT score are currently used to predict HCC recurrence after LT. However, superior discriminating models are needed for low AFP populations. The aim of this study is to investigate the predictive value of PIVKA-II on recurrence-free survival after LT in a low AFP population and microvascular invasion on explant. Methods: A retrospective cohort study including all consecutive patients transplanted for HCC between 1989 and 2019 in the Erasmus MC University Medical Center in Rotterdam, the Netherlands, was used. AFP and PIVKA-II levels were determined in serum samples collected at the time of transplantation. Data on tumor load and microvascular invasion were retrieved from patients' records. Results: The study cohort consisted of 121 patients, with HCC recurrence in 15 patients (12.4%). The median AFP was 7.7 ng/mL (4.4-20.2), and the median PIVKA-II was 72.0 mAU/mL (41.0-213.5). Patients with low AFP (<= 8 ng/mL) and PIVKA-II (<= 90 mAU/mL) had a 5-year recurrence-free survival of 100% compared to 85.7% in patients with low AFP and high PIVKA-II (p = 0.026). Regardless of the AFP level, patients within the Milan criteria (based on explant pathology) with a low PIVKA-II level had a 5-year recurrence-free survival of 100% compared to patients with a high PIVKA-II level of 81.1% (p = 0.002). In patients with microvascular invasion, the AUC for PIVKA-II was slightly better than the AUC for AFP (0.775 vs. 0.687). Conclusions: The dual model of PIVKA-II <= 90 mAU/mL with either AFP <= 8 ng/mL or with patients within the Milan criteria identifies patient groups which can be exempted from HCC surveillance after LT in a low AFP population. PIVKA-II may be a better predictor for explant microvascular invasion than AFP and could play a role in future models identifying LT candidates with the highest risk for HCC recurrence.