Case-control study of gestational choriocarcinoma

A multicentered case-control study of 75 women who had had gestational choriocarcinoma was conducted to investigate the role of reproductive and fertility factors as well as other potential risk factors in the development of this disease. Control women, identified through random digit dialing, were individually matched to cases by year of pregnancy, age at pregnancy, and geographical proximity of residence. Choriocarcinoma risk was decreased significantly as body mass index increased (P for trend = 0.03). Cases reported low-calorie dieting significantly less frequently than controls [odds ratio estimate (OR) = 0.50, P = 0.05] and were significantly less likely to participate in regular exercise (OR = 0.38, P = 0.004). Compared to women with a heavy menstrual flow, those with light menstruation had significantly elevated risk (OR = 6.69, P = 0.01). Menarche after age 12 was also associated with elevated risk of this disease (OR = 2.89, P = 0.003). There were significantly more pairs of dizygotic twins born to cases and their first degree relatives than to controls (12 case families with 13 sets of twins versus 3 sets in control families, OR = 6.36, P = 0.009). Cases were more likely to have married more than once (OR = 13.0, P less than 0.001), and infrequent intercourse was a significant risk factor (OR for weekly or less often was 3.00, P = 0.04). Risk estimates for postmolar choriocarcinoma were not significantly different from those for all other cases. These observations and some descriptive features of the disease suggest that hormonal factors, specifically below normal estrogen levels, may be associated with a disruption of normal ovulation and thus predispose to choriocarcinoma.