Family breast cancer history ups ovarian cancer risk

A breast cancer family history, as well as a woman's age and her own personal history of breast cancer, may help identify women at increased risk of developing ovarian cancer.

A family history of breast cancer has been associated with increased ovarian cancer risk. However, they note that few studies have assessed risk according to a wide variety of traits that suggest an inherited cancer susceptibility disorder.

For their study, Dr. Catherine Schairer and colleagues from the National Cancer Institute, Rockville, Maryland, assessed ovarian cancer according to a detailed breast cancer family history among 49,975 subjects enrolled in a breast cancer study. A total of 362 cases of ovarian cancers were identified during follow-up.

The team found that having a first- or second-degree relative with breast cancer was associated with a 40 percent increased risk of ovarian cancer (relative risk, 1.4).

The risk was nearly twofold higher among women with two or more affected first-degree relatives (relative risk, 1.8). This was especially true for women diagnosed with ovarian cancer before age 60 or with a personal history of breast cancer.

The highest relative risks were observed among women with a personal history of breast cancer and at least two first-degree relatives with breast cancer, at least one of whom was diagnosed before age 50 or with bilateral breast cancer.

"Knowledge of the familial component of ovarian cancer risk can be used to inform decisions regarding whether to obtain genetic testing, screening, or undertake preventive measures," Schairer and colleagues conclude.

"In light of ovarian cancer's tendency to present at a late stage and its attendant high mortality rate, the need to identify women at particularly high risk is clear."

SOURCE: Cancer September 2006.