Ovarian germ cell malignancies in England: epidemiological parallels with testicular cancer.

The epidemiology of germ cell cancer of the ovary has been little investigated. We studied ovarian germ cell cancers incident 1971-84 in England, using data from the England and Wales national cancer register. The age distribution showed a sharp peak at ages 15-19, to which both teratomas and dysgerminomas contributed equally, and a secondary, much wider peak, at ages 65-69, mainly due to teratomas. For teratomas there were diverging secular trends by age: incidence has been increasing at ages 0-44 (P around 0.05) and decreasing at ages over 44 (P less than 0.01). Birth cohort analysis showed an increase in risk at ages 0-44 for more recent generations of women. There were no changes over time for dysgerminomas. There was no clear geographic pattern of distribution across the regions of England. The early age peak, and the increase in incidence of ovarian germ cell cancers at young ages but decrease at older ages, resembles testicular cancer epidemiology. Interestingly, discrepancies and similarities in the age distribution of these tumours between the sexes parallel lifetime profiles of gonadotropin levels in each sex.