Background: Lens culinaris agglutinin-reactive fraction of α-fetoprotein (AFP-L3) is a specific marker used to detect hepatocellular carcinoma (HCC). However, its clinical utility is not sufficient in patients with low total AFP concentrations because of limitations in instrument sensitivity. Recent advances have led to the introduction of a highly sensitive AFP-L3% assay (sensitive AFP-L3%), provided by a novel on-chip, liquid-phase binding assay. This cross-sectional study was conducted to evaluate the clinical significance of the sensitive AFP-L3% in determining HCC recurrence in patients with low total AFP concentrations.
Methods: A total of 370 consecutive patients with HCC were screened within 1-3 months of locoregional treatment, and 215 of the 370 patients showed serum AFP <20 ng/ml. Total AFP, sensitive AFP-L3%, and des-gamma-carboxy prothrombin (DCP) were measured in those 215 patients and HCC recurrence was evaluated by radiological findings. Optimal cutoff values of the markers for detecting HCC recurrence were obtained on the basis of receiver operating characteristic (ROC) curve.
Results: The area under the ROC curve of the total AFP, sensitive AFP-L3%, and DCP in HCC patients with serum AFP <20 ng/ml were 0.638, 0.724, and 0.779, respectively. The diagnostic accuracies of the total AFP, sensitive AFP-L3%, and DCP were 60.9% (cutoff value 5 ng/ml), 67.7% (cutoff value 7%), and 64.6% (cutoff value 40 ng/ml), respectively.
Conclusions: The new sensitive AFP-L3% assay provides great utility in determining HCC recurrence in patients with low AFP concentrations. Further studies focusing on the combinatorial use of the markers (total AFP, sensitive AFP-L3%, and DCP) are required.