Objective: To provide age-specific risks for ovarian cancer for relatives of ovarian cancer case patients. To characterize the age at onset for ovarian cancer for women with a single relative vs several relatives affected with ovarian cancer.
Design: Three previous studies were reexamined. The cumulative probability of ovarian cancer in first-degree relatives of women with histologically confirmed epithelial ovarian cancer and matched control subjects who participated in the Cancer and Steroid Hormone (CASH) Study was determined. The age of onset of ovarian cancer in women with and without relatives with ovarian cancer in a Washington, DC, case-control study was contrasted with that of women with at least two first-degree relatives studied at the National Cancer Institute (NCI).
Results: The CASH Study data showed that first-degree relatives of women with ovarian cancer had an increased risk for ovarian cancer, especially at older ages, when compared with relatives of control subjects. However, the median age at onset was the same among women in the Washington, DC, study with and without an affected relative. Among the women with an extensive family history of ovarian cancer studied at the NCI, the age at onset was considerably younger (47 years) than is typical for this disease (59 years). Of these, 17% had been diagnosed as having primary ovarian cancer by age 40 years.
Conclusions: Women who have one first-degree relative affected by ovarian cancer are at greater risk for ovarian cancer but not at an age earlier than the general population. The small proportion of women who have several affected relatives are, however, at a greater risk of early onset of ovarian cancer. Prophylactic oophorectomy may be reasonable for these women.