Diagnostic value of alpha-1-fetoprotein (AFP) as a biomarker for hepatocellular carcinoma recurrence after liver transplantation

Abstract

Background: Alpha-1-fetoprotein (AFP) is used to monitor progression, evaluate response to therapy and predict recurrence of hepatocellular carcinoma (HCC) in liver transplantation (LTx) patients. To date, the diagnostic value of serum AFP determinations for detecting tumor recurrence in HCC patients after LTx is unclear.

Objective: A retrospective, single-center, cross-sectional, non-interventional study was performed with the objective of determining post-transplant cut-off AFP values for detecting HCC recurrence post LTx.

Methods: Using receiver operating characteristic (ROC) analyses, post-transplant serum AFP values were evaluated against HCC recurrences in 63 HCC patients who had LTx between November 1995 and December 2011 at the University Medical Center Göttingen (UMG). Optimal and application-independent cut points for predicting tumor recurrence at 1, 3, and 5years after LTx were determined.

Results: Post-LTx serum AFP was found to represent an independent risk factor (predictor) for HCC relapse. Post-operative AFP cut-off values of 7μg/l, 6μg/l, and 6μg/l, respectively, were determined to be optimal at 1, 3, and 5years after LTx respectively for predicting a HCC relapse. Using these cut-off values, patients were correctly classified as relapse-positive with a diagnostic sensitivity of 79%, 81%, and 77%, and as relapse-free with a specificity of 82%, 79%, and 69%. The diagnostic accuracy measured by area under the curve (AUC) values ranged from 0.813 to 0.886. However, a limitation is that at a clinically relevant specificity of ≥95%, the analyses showed sensitivity values of only 50%, 52%, and 50%, respectively.

Conclusion: Post-transplant serum AFP may have diagnostic value to detect HCC recurrence after LTx.

Keywords: Alpha-1-fetoprotein; Cut-off values; Hepatocellular carcinoma; Liver transplantation; Recurrence.