UK registration scheme for hydatidiform mole 1973–83

During the 1960s it became clear that many patients with choriocarcinoma were curable by chemotherapy (Hertz et al. 1961; Bagshawe 1963). At about the same time, detection of this tumour following hydatidiform mole and detection of invasive mole which was failing to regress was advanced by the development of immunoassays which replaced laborious techniques for human chorionic gonadotrophin (hCG). Even so, some patients died or needed prolonged chemotherapy because they defaulted follow-up or because local follow-up arrangements broke down. A Registration Scheme for patients with hydatidiform mole in the UK was established in 1973 under the auspices of the Royal College of Obstetricians and Gynaecologists and the DHSS to collect data and provide an economical and reliable follow-up system with hCG -assays. During the first 11 years of the scheme 8095 patients were registered at the three designated centres in Dundee, Sheffield of London. The number of patients registered annually doubled between 1975 and 1983 and in 1983 registrations totalled 1.525 per loo0 live births. This is a higher number than previous estimates (Stevenson et al. 1959; Womack & Elston 1985) had suggested and possible reasons for this will be discussed later. Under the Registration Scheme patients send serum or urine samples by standardized schedules to the designated centre. Additional information about menstruation and contraception was requested by the London centre (Bagshawe etal. 1973). Data from the 5124 patients registered between 1973 and 1983 at the London (Charing Cross) centre were presented at the 2nd World Congress on Trophoblastic Neoplasms held in Singapore in November 1984 (Dent & Bagshawe 1986). The risk of a pregnancy resulting in hydatidiform mole was lowest between 25 and 29 years when compared with the number of live births in that age group but it increased progressively towards both ends of reproductive life. Compared with the number of live births the risk of hydatidiform mole was six times greater in pregnancies occurring under 15 years of age and 400 times greater for those over 50 years. It is of course possible that these numbers are distorted by the frequency of pregnancy termination at the extremes of reproductive life. Standardized criteria were used for identifying the 7.75% of the registered patients with hydatidiform mole who were subsequently judged to need chemotherapy. These criteria have been summarized (Bagshawe et al. 1973; WHO Technical Report 1983) but they are not universally used and in the USA several centres have reported treating 2Q-36% of patients with hydatidiform mole with cytotoxic agents (Lurain etal. 1983). As reported in an earlier analysis of the series (Stone & Bagshawe 1979) patients who had a medical induction with oxytocin or prostaglandins, or a hysterotomy to terminate the molar pregnancy had a significantly higher risk of requiring chemotherapy than those who had a spontaneous expulsion of the hydatidiform mole, or suction curettage or who had salpingectomy for a tuba1 mole. A possible common factor in the high-risk methods is displacement of trophoblast from intravascular locations by uterine contraction or manipulation but this does not explain the increased risk of delayed regression of the trophoblast or its possible malignant transformation. The earlier analysis of the series also suggested an increased risk of requiring chemotherapy for patients who took steroid contraceptives whilst their serum or urine hCG values were still elevated and this has provoked both supportive and contrary evidence from North America. In a further analysis of the Charing Cross data, 233 patients reported taking steroid contraceptives during the 6-month period following evacuation of the mole whilst hCG was still detectable in serum or urine. These patients were matched for year of evacuation, hCG value (+20%) and interval between evacuation of mole and starting contraception