Gender, a Breast Cancer Risk Factor
It’s surely not surprising that women are far more at risk than men for developing breast cancer. Males and females are both born with breast tissue, but the naturally elevated testosterone levels in males prevents the growth of mature breast tissue. This leaves males with a small amount of underdeveloped breast tissue. Male breast cancer makes up about 1 percent off all breast cancer.
About 12 percent of women in the general population have a lifetime risk for developing breast cancer. That’s around one in eight women. For men, the lifetime risk for breast cancer is much lower: around one in a thousand.
Besides females having higher levels of estrogen than men, other risk factors can increase breast cancer in both male and females. Male risk factors for breast cancer are similar to risk factors in females, and although estrogen increases breast cancer risk for women, when women have certain diseases or are exposed to environmental toxins, their risk for breast cancer is much higher. Factors that might increase estrogen levels in males can also increase their risk of developing breast cancer.
The following are shared risk factors for breast cancer in both men and women:
- Being older: The average age when men get breast cancer is between 68 and 71 years. For women, it’s 50 to 69 years.
- Inherited gene mutations: The mutation defect in BRCA 1 or BRCA 2 can increase the lifetime risk of getting breast cancer to 6 in 100. Both men and women may carry the gene. We talk more about genetics later in this chapter.
- Liver disease: Cirrhosis of the liver can cause male hormones to be reduced, which can ultimately increase female hormones. In females, liver disease causes estrogen levels to surge to significantly higher levels.
- Alcohol: Heavy drinking can affect the liver, increasing the risk of breast cancer.
- Radiation exposure: If a man or woman has received radiation to the chest wall for cancer (for example, for lymphoma) they may develop breast cancer later in life.
- Obesity: Fat cells convert androgens to estrogens in men when they are overweight, especially in the abdomen. In women, the fat cells may convert to estrogen, placing the body in estrogen overload.
Here are risk factors for men only:
- Testicular disease or surgery: If his testicle is diseased or has been removed, then the man is more at risk for developing breast cancer.
- Occupation: Working in industries that require men to work in a heated or hot environment, such as steel mills, or in jobs with increased exposure to gasoline fumes, can affect testicles, thus increasing risk for breast cancer.
- Klinefelter syndrome: This occurs if a boy is born with more than one copy of the X chromosome, causing him to have more female hormones.