Are serum inhibin concentrations new markers of placental tumours in the course of chemotherapy?

Background: The study was conducted to evaluate whether the detection of serum molecular forms of inhibin (A and B) could be useful for the diagnosis, prognosis and follow-up of placental tumours. Methods: A total of 17 patients with hydatidiform mole (n = 13), invasive mole (n = 1) or choriocarcinoma (n = 3) were studied; serum concentrations of inhibins A and B, human chorionic gonadotrophin (HCG) and its free β subunit (HCGβ) were measured before chemotherapy (after mole evacuation for eight patients) and also during the course of chemotherapy (for 10 patients). Results: After evacuation or before chemotherapy for refractory disease, serum inhibin A and B concentrations were found to be increased in 10/17 and 4/17 patients, when HCG and HCGβ were high in all patients. In 10 patients with a follow-up during treatment, nine had a high concentration of inhibin A which correlated with those of HCG and HCGβ. Normalization of inhibin A was faster than that of HCG and HCGβ for three and six patients respectively. There was no correlation between changes of inhibin B and HCGβ concentrations. Conclusions: Our results suggest that inhibins A and B are not useful markers and that HCG determination still remains the most useful marker for diagnosis and follow-up of placental tumours.