Male breast cancer occurs when malignant cells form in the tissues of the breast. Any man can develop breast cancer, but it is most common among men who are 60–70 years of age. About 1% of all breast cancers occur in men. About 2,000 men are diagnosed with breast cancer annually, with about 450 deaths due to male breast cancer occurring each year.

Many men may be surprised to learn that they can get breast cancer. Men have breast tissue that develops in the same way as breast tissue in women, and is susceptible to cancer cells in the same way. In girls, hormonal changes at puberty cause female breasts to grow. In boys, hormones made by the testicles prevent the breasts from growing. Breast cancer in men is uncommon because male breasts have ducts that are less developed and are not exposed to growth-promoting female hormones.

Just like in women, breast cancer in men can begin in the ducts and spread into surrounding cells. More rarely, men can develop inflammatory breast cancer or Paget’s disease of the nipple, which happens when a tumor that began in a duct beneath the nipple moves to the surface. Male breasts have few if any lobules, and so lobular carcinoma rarely, if ever, occurs in men.

Men should also be aware of gynecomastia, the most common male breast disorder. Gynecomastia is not a form of cancer, but does cause a growth under the nipple or areola that can be felt, and sometimes seen. Gynecomastia is common in teenage boys due to hormonal changes during adolescence, and in older men, due to late-life hormonal shifts. Certain medications can cause gynecomastia, as can some conditions, such as Klinefelter syndrome. Rarely, gynecomastia is due to a tumor. Any such lumps should be examined by your doctor.

Male Breast Cancer Risk Factors

Any man can develop male breast cancer. Factors that may increase risk include:

Age:  Male breast cancer is most common among men age 60–70.

Alcohol: Excessive consumption of alcohol may increase risk.

Exposure to radiation:  Men who have undergone radiation treatment to the chest, such as for the treatment of cancer, are more likely to develop breast cancer.

High estrogen levels:  Having a disease connected to increased amounts of estrogen in the body, such as cirrhosis or Klinefelter syndrome (a genetic disorder).

Family history:  Having several female relatives who have had breast cancer, especially those with a mutation of the BRCA2 gene.

Weight: Men who are obese may be at greater risk for male breast cancer. Fat cells convert the male hormone androgen into the female hormone estrogen, which may lead to an increased amount of estrogen in the body, possibly triggering breast cancer.

If you have several male breast cancer risk factors, talk with your doctor to ensure he or she can monitor your health appropriately.