For African-American men, the chances of developing prostate cancer are increased if a sister has breast cancer, according to a study by researchers at the University of Michigan, Ann Arbor.

“Previous studies have suggested that having a brother with prostate cancer confers a higher risk than another relative, such as a father or son,” Dr. Jennifer L. Beebe-Dimmer noted in a written statement. “But this is the first time a link has been shown between sisters with breast cancer and prostate cancer risk among African-American men.”

Dr. Beebe-Dimmer and colleagues explored the clustering of prostate and breast cancer in families, by studying data on 121 African-American men with prostate cancer and 179 without prostate cancer. Their findings appear in the medical journal Urology.

After taking account of age, the researchers found that men with prostate cancer were 4.8 times more likely than men without prostate cancer to have a brother with prostate cancer, and 3.8 times more likely to have a sister with breast cancer.

“Collecting a family history of prostate and breast cancer, particularly among siblings, could be a key component in the clinical assessment of prostate cancer risk among African-American men,” the team writes.

“A well-documented family history of all cancer among first-degree relatives may signal a need for more aggressive prostate cancer screening practices and the adoption of screening at an earlier age,” they add.

SOURCE: Urology, November 2006.