Hyperglycosylated hCG in the management of quiescent and chemorefractory gestational trophoblastic diseases

IntroductionThe literature shows that hyperglycosylated hCG is the invasion stimulus in malignant gestational trophoblastic diseases. The USA hCG Reference Service has characterized 2 gestational trophoblastic disease conditions marked by low proportion of hyperglycosylated hCG. These are quiescent gestational trophoblastic disease, defined as inactive or benign invasive disease, and minimally invasive gestational trophoblastic disease, defined as slow growing or chemorefractory disease with hCG increasing very slowly (doubling rate 2–6 weeks). Here we examine the USA hCG Reference Service experience with both diseases.MethodsPatient were referred to the USA hCG Reference Service, 133 cases shown to have quiescent gestational trophoblastic disease, 35 cases with aggressive and 30 with minimally invasive gestational trophoblastic disease.ResultsQuiescent or inactive gestational trophoblastic disease was demonstrated in 133 women. In 127 of these cases, no hyperglycosylated hCG was detected, and in 6 cases 4–27% hyperglycosylated hCG was detected. This is quiescent or inactive disease.Only 1 of 35 cases with aggressive gestational trophoblastic disease (> 40% hyperglycosylated hCG) was chemorefractory. In contrast, 30 of 30 minimally invasive cases (< 40% hyperglycosylated hCG) were chemorefractory. In chemorefractory cases hyperglycosylated hCG ranged from < 1% to 39% of total hCG. The USA hCG Reference Service showed that proportions hyperglycosylated hCG significantly increases as total hCG rises. They recommended in minimally invasive cases to wait to hCG was > 3000 IU/L before commencing chemotherapy. This was successful in 10 of 10 minimally invasive cases.DiscussionMeasurement of hyperglycosylated hCG or invasiveness is a critical step in management of invasive gestational trophoblastic disease. Quiescent of inactive gestational trophoblastic disease requires no therapy. Minimally invasive disease in chemorefractory. The USA hCG Reference Service experience suggests waiting until hCG exceeds 3000 IU/L before commencing any chemotherapy.