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Study Finds Breast Cancer Risk Linked to Family History of Prostate Cancer (dateline June 20, 2000)


According to a new study published in the June issue of the International Journal of Cancer, women who have a first-degree relative (father or brother) who had prostate cancer may be at a higher risk of developing breast cancer than women who do not have this family history.  Furthermore, the younger the male family member was diagnosed with prostate cancer, the greater the woman’s chances that she will develop breast cancer . Though the results of the study are preliminary, if additional research confirms these findings, women with a family history of prostate cancer may need to be more closely monitored by physicians for breast cancer.

In a French study of 691 men with prostate cancer, those men who had at least one first degree relative who had prostate cancer were more than twice as likely to also have a female first-degree relative with breast cancer (mother or sister).  The men who were diagnosed with prostate cancer before age 55 were approximately 5.5 times as likely to have a first-degree relative with breast cancer. 

In the study, the researchers also found that if a man was diagnosed with prostate cancer before age 55, his mother was 30 times more likely to have breast cancer than if the man was diagnosed with prostate cancer after age 75.   According to the researchers, this shows that the age of cancer diagnosis may be important: the younger a man is diagnosed with prostate cancer, the more likely his mother, sister, or daughter may have breast cancer. 

According to Antoine Valeri, MD, of the Center of Research for Prostate Pathology in Evry, France, the results of the study suggest that breast cancer screening may be needed in prostate cancer families where two or more men have the disease or among families whose male members developed prostate cancer at an early age.   However, U.S. researchers say it is too early to change the mammography guidelines for women with a family history of prostate cancer. 

Currently, the American Cancer Society recommends that women begin receiving yearly screening mammograms at age 40.  Women who are at high risk of breast cancer (such as those with a strong family history of breast cancer or those who test positive for BRCA gene mutations ) may wish to ask their physicians begin mammography at an earlier age, as early as age 25 in some cases.   

According to Dr. Valeri, the researchers are unsure why a family history of prostate cancer may increase a woman’s risk for breast cancer but hypothesize that the link may occur due to common predisposing genes.  The researchers thought that perhaps BRCA gene mutations might be involved since women who are found to have a mutation of the BRCA1 or BRCA2 gene are known to be at a higher risk of developing breast cancer.  BRCA gene mutations account for 5% to 10% of hereditary breast cancer cases.  

However, in the study, only 2% of the men were found to have a BRCA gene mutation.  Additional studies are focusing on other possible genetic factors that may explain why a family history of prostate cancer could increase breast cancer risk.  Dr. Valeri suggests that there may be a several different genes or genetic mutations involved that could explain the link between prostate cancer and breast cancer.  

To help detect breast cancer early when the chances for minimally invasive treatment and survival are the greatest, women should following the American Cancer Society’s guidelines for early detection :

  • Women 20 years of age and older should practice monthly breast self-exams and have a physician-performed clinical breast exams at least every three years.
  • Women 40 years of age and older should practice monthly breast self-exams, have physician-performed clinical breast exams every year, and begin yearly mammograms. 
  • Women at high risk of breast cancer (such as those with a strong family history of breast cancer or those who test positive for BRCA gene mutations) should talk to their physicians about beginning annual mammograms before age 40.

Additional Resources and References