Male Breast Cancer Support Group

Today, breast cancer, like other forms of cancer, is considered to be a result of damage to DNA. How this mechanism may occur comes from several known or hypothesized factors (such as exposure to ionizing radiation). Some factors lead to an increased rate of mutation (exposure to estrogens) and decreased repair (the BRCA1, BRCA2 and p53 genes). Although many epidemiological risk factors, and biological co-factors and promoters have been identified, the majority of breast cancer incidence remains unattributable, and the primary cause is unknown.

Dietary influences have been proposed and examined, but these are small effects, and do not distinguish differences in risk within populations, as well as they do between populations.

A significant environmental effect was revealed by the large difference in breast cancer incidence between countries and continents, and a migration effect which slowly increases the risk of breast cancer even across generations after migration from a country of lower incidence to a country of higher incidence, such as moving from China or Japan to the United States.

The risk of getting breast cancer increases with age. For a woman who lives to the age of 90 the chances of getting breast cancer her entire lifetime is about 12.5% or one in eight. Men can also develop breast cancer, but their risk is less than one in 1000 (see sex and illness). [citation needed] This risk is modified by many different factors. In a very small (~ 5%) proportion of breast cancer cases, there is a strong inherited familial risk.

Two genes, BRCA1 and BRCA2, have been linked to the rare familial form of breast cancer [citation needed]. Women in families expressing mutations in these genes have a much higher risk of developing breast cancer than women who do not. Not all people who inherit mutations in these genes will develop breast cancer. Together with Li-Fraumeni syndrome (p53 mutations), these genetic aberrations determine around 5% of all breast cancer cases, suggesting that the remainder is sporadic. Genetic counseling and genetic testing should be considered for families who may carry a hereditary form of cancer.

Alcohol generally appears to increase the risk of breast cancer in women. The U.K.s Review of Alcohol: Association with Breast Cancer concludes that "studies confirm previous observations that there appears to be an association between alcohol intake and increased risk of breast cancer in women. On balance, there was a weak association between the amount of alcohol consumed and the relative risk."