Women who have a first-degree relative with prostate cancer are at increased risk for developing breast cancer, suggests an article in the journal Cancer. 

Roughly 78,000 postmenopausal women from the Women’s Health Initiative Observational Study provided family cancer histories at baseline. Roughly 4% of women were diagnosed with breast cancer over a median 11 years’ follow-up.

Having a first-degree relative with prostate cancer was slightly more common among women with breast cancer than among those without (11.6% vs 10.1%). The association persisted after adjusting for family history of breast. Women who had family histories of both breast and prostate cancers had higher risk,  and African American women with family histories of both types of cancer had even greater risk.

The authors conclude: “Risk communication between the physician and the patient as well as the dissemination of this information from the patient to immediate relatives would be important in shaping the health behaviors (such as screening for early detection) of those family members, even among those of the opposite sex.”