[Prevention of the malignant form of trophoblastic disease after a hydatidiform mole: systematic or selective chemotherapy].

After a mole has been evacuated there are two ways of treating the condition: routine chemotherapy from the beginning or chemotherapy reserved for selected cases. They offer the same chances of cure. Seeing that the risk of malignancy in our country is 5 per cent and that selective chemotherapy only exposes a small number of patients to the risk of such treatment, we have adopted the scheme of follow-up suggested by Bagshawe and recommended by OERTC. The follow-up is based on radio-immune assay for HCG carried out at regular intervals for two years. Only cases where the level of HCG is higher than 25,000 international units per litre, one month after curettage, or cases where the rise in HCG is associated with metastases, are treated with chemotherapy. In our experience, which is based on 20 cases, we acknowledge the value of radio-immune assaying. It is superior to immunological tests used for pregnancy diagnosis in sensitivity. It also appears to us that systematic treatment routinely administered and treatment based on raised levels of HCG two months after evacuation of a mole are useless. Only 3 cases were treated with chemotherapy out of the 20 cases that were followed up. We have had no malignancy after 2 and 3 years of checking back on the patients. Treatment given routinely from the start would have been unnecessary exposure to the risks of chemotherapy for 17 patients. Had we taken into account the abnormal rise in HCG after 8 weeks we would still have treated 7 patients instead of 3 with the same results as far as cure. We have worked out a graph for the drop in the levels of HCG after a mole has been evacuated. This may serve as a base for criteria for treatment in the future. Cases where the levels of HCG are above the 95 percentile are considered as at risk to evolve into malignant forms of disease. Consequently earlier treatment can be started (before the 6th month) without altering the number of patients who are going to be treated.