Abstract
Objective
Human chorionic gonadotropin (hCG) is widely used in the management of hydatidiform mole and persistent trophoblastic disease (PTD). Studies on hyperglycosylated human chorionic gonadotropin (invasive trophoblast antigen, ITA) in PTD are limited. In serum samples taken before evacuation of molar pregnancies we measured the concentrations of free hCG β-subunit (free hCGβ), “total” hCG (hCG+hCGβ) and ITA, and determined whether ITA, the two other hCG analytes, or the calculated ratios of hCGβ/hCG+hCGβ, hCGβ/ITA and hCG+hCGβ/ITA could predict the later development of PTD.
Design
A retrospective study based on blood specimens collected in the Dutch Central Registry for Hydatidiform Moles. The study group comprised 97 patients with hydatidiform moles who did not develop PTD after mole evacuation and 33 patients who did develop PTD.
Methods
Serum samples from 130 patients with hydatidiform mole with or without PTD were assayed using specific (radio)immunoassays for free hCGβ, total hCG, and ITA. From these analytes we also calculated the ratios hCGβ/hCG+hCGβ, hCGβ/ITA, and hCG+hCGβ/ITA. To predict the development of PTD from these analytes and parameters we performed receiver-operating characteristic (ROC) curve analysis, resulting in areas under the curve (AUCs) that represented the diagnostic accuracy which was rated in a range from excellent (AUC >0.9 or <0.1) to poor (AUC 0.4–0.6).
Results
The diagnostic accuracy of ITA was moderate (0.618) and not different from that of free hCGβ (0.610) and hCG+hCGβ (0.622).
Conclusions
ITA as well as the other analytes and parameters in serum taken prior to evacuation from patients with molar pregnancies cannot be used to predict the subsequent development of persistent trophoblastic disease.