Family History of Other Types of Cancer
It has been suggested that men with a family history of breast cancer in their mother or sisters may have an increased risk of prostate cancer. Both cancers are hormone dependent and thus there may be some genetic relationships. There is some preliminary evidence that mutations of the breast cancer genes, BRCA1 and BRCA2, may increase the risk of prostate cancer.
The epidemiological evidence is limited, but two prospective studies have confirmed the relationship. The largest prospective study that investigated the family history of nearly 500,000 men, including over 3,000 who died from prostate cancer over a 12-year period, found that having a female relative diagnosed with breast cancer before age 50 increased the risk of prostate cancer by about 1.6 times. In another cohort study from Iowa, men with a family history of both prostate and breast cancer had the highest risk. Further research needs to confirm this relationship, but a man with breast cancer in his family may need to pay closer attention to screening for prostate cancer.
