Objective: To provide estimates of the age-adjusted incidence and lifetime risk of ovarian cancer in subgroups of women defined by key risk factors.
Methods: We combined data from seven case-control studies (1122 cases and 5359 controls) with Surveillance, Epidemiology, and End Results incidence data to estimate the incidence rate and probability of developing ovarian cancer within subgroups of women defined according to the three major known risk factors: a history of ovarian cancer in the mother or sister, years of oral contraceptive (OC) use, and number of term pregnancies.
Results: Among women with no family history of ovarian cancer, the risk at age 65 varied from 0.3% among those who had had three or more term pregnancies and 4 or more years of OC use, to 1.6% among nulliparous women with no OC use. Among women with a positive family history, the risk of developing ovarian cancer by age 65 was estimated as 4.4% and the lifetime risk as 9.4%. The data were too sparse to estimate the risks associated with OC use and pregnancy among women with a positive family history.
Conclusions: The risk of developing ovarian cancer within the total population of white women can be divided informatively into component risks within subpopulations. At birth, the estimated risk of developing ovarian cancer before age 65 for the total population is 0.8%, but the component risks vary 15-fold, from 0.3 to 4.4%.