Family History and the Risk of Prostate Cancer

Prostate cancer is the most common malignancy in American men and the second most common cause of cancer deaths. Because prostate cancer produces no symptoms until it is far advanced, at least 40% of men have metastatic disease--disease that has spread--at the time the tumor is detected. Recognizing the high incidence and mortality of this disease, early detection of prostate cancer is of vital importance.

Most women in the United States are aware of the close association between a family history of breast cancer and their risk of developing the disease and recognize that if their mother or sister has the disease they are twice as likely to be affected. Up to this point, however, important information such as this has not been available for men with prostate cancer.

Thanks to the participation of many of you, we have just completed a study comparing the family history of prostate cancer in 690 men with prostate cancer and 640 spouses who were used as controls. Fifteen percent of the men with prostate cancer had a brother or father affected with the disease as opposed to only 8% of the spouses. Men with father or brother affected with the disease were twice as likely to develop prostate cancer as men with no affected relatives. In addition, with increasing numbers of affected family members the risk increased, e.g. men with 2 or 3 first degree affected relatives had a five- and 11-fold increased risk of developing prostate cancer (Table 1).

Recognizing that 9-10% of men in the United States will develop prostate cancer in their lifetime, men with a family history of prostate cancer should be advised of their significantly increased prostate cancer risk and after age 40 should undergo yearly digital rectal examinations. In the future, other screening measures may prove useful, e.g. serial prostate specific antigen (PSA) determinations, transrectal ultrasound, or magnetic resonance imaging of the prostate. This is important information for your brothers and sons. We are actively searching for genetic probes that may help us identify individuals at the greatest risk for developing the disease.