False elevations of human chorionic gonadotropin associated to iatrogenic hypogonadism in gonadal germ cell tumors

Abstract

Radioimmunoassay (RIA) for fraction beta of the chorionic gonadotropin hormone (HCG-beta subunit) has a clinical value in the management of patients with gonadal germ cell tumors (GCT). Treatment of disease causes temporary or permanent iatrogenic hypogonadism and secondary plasmatic elevations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Small but significant cross-reactions with LH have been observed, resulting in spurious elevations of HCG, as result, also in part, of the lack of specificity of the RIA. Twelve patients with complete response showed high HCG follow-up levels between 1.7 and 7.8 mIU/ml; simultaneous determination of LH and FSH resulted, also, in high levels: 79.9 to 24.9 mIU/ml and 80 to 19.2 mIU/ml, respectively, in females, and 78 to 18 mIU/ml and 65.1 to 5 mIU/ml, respectively, in males. Administration of exogenous hormones resulted in all cases in reduction of LH and FSH values and normalization of HCG. Therefore, relationship between spurious elevations of HCG and the iatrogenic hypogonadism is clarified through this simple technique that is of most importance as regards the adoption of the appropriate therapy.