Childhood and adolescent ovarian malignant tumors in Israel. A nationwide study

To determine the incidence of ovarian malignant tumors in childhood and adolescence, to ascertain the frequency distribution of the various tumor types and to assess time trends in Israel on a nationwide basis.

The study group included all Israeli Jewish patients < or = 19 years old with histologically confirmed ovarian malignancies, diagnosed in Israel from 1970 to 1994. Data were obtained from the Israel Cancer Registry. The effects of age at diagnosis and period of diagnosis were analyzed using the Poisson regression.

Among the 82 patients identified, the most frequent tumors (72.0%) were of germ cell origin and among those about one third were dysgerminomas. Epithelial tumors were diagnosed in 26.6% of the patients and most of these were borderline malignancies. The incidence rate (IR) for the total group of ovarian malignancies in the 0-19 age group was 0.52 and for ages 5-19 it was 0.71 per 100,000. After adjustment for age, a significant linear trend for a decrease of germ cell tumors over time was found, stemming from a decrease of dysgerminomas. A significant trend for increase in the IRs with age was also found. In addition, a steep rise in the age specific IRs of epithelial borderline tumors was noted in the last 5 year period.

The IRs of ovarian malignancies in childhood and adolescence in Israel, as in other countries, is very low as compared to adults and the most common tumors are of germ cell origin while malignant epithelial tumors are very rare. A time period effect in the germ cell tumors that resulted from an inexplicable significant decrease in the age specific IRs of dysgerminomas, was observed. A significant increase in borderline tumors was also noted and may be attributed to greater awareness of pathologists to this entity.