What is male breast cancer?

Breast cancer happens when cells grow out of control inside the breast. Cancer in the breast can spread to other parts of the body.

Breast cancer isn’t only a woman’s disease. Men can also get breast cancer, although it’s rare.

Symptoms of male breast cancer are the same as those in women. But because men don’t regularly check their breasts or get mammograms, the signs are easier to miss.

Call your doctor if you notice any of these symptoms:

  • a lump in one breast
  • a nipple that pushes inward (inverted nipple)
  • discharge from the nipple
  • pain in the nipple
  • redness, scaling, dimpling, or other changes to the skin over the breast
  • redness or sores on the nipple and areola (the colored ring around the nipple)
  • swollen lymph nodes under your arm

It’s important to note that breast enlargement in men isn’t a sign of breast cancer. When this happens, it’s called gynecomastia, and it may be due to weight gain or the use of certain medicines.

Men do have breast tissue, just like women. The difference is in the amount of tissue they have.

Before puberty, boys and girls have the same amount of breast tissue. Breast tissue is made up of milk-producing glands called lobules, ducts that transport milk to the nipples, and fat.

At puberty, girls’ ovaries start producing female hormones. These hormones cause the breasts to grow. Boys don’t produce the same hormones, so their breasts stay flat. Sometimes a man’s breasts can grow because he takes certain hormones or if he’s exposed to hormones in the environment.

Men can develop a few different types of breast cancer:

  • Ductal carcinoma is an early cancer that starts in the milk ducts.
  • Lobular carcinoma starts in the milk-producing glands.
  • Paget disease starts in the breast ducts, and then spreads to the nipple.
  • Inflammatory breast cancer makes the breast swell up and turn red. It’s very rare, but also very aggressive.

Although breast cancer is rare in men, it’s important to know if you’re at risk. That’s because men aren’t routinely screened for breast cancer like women are.

Risks for male breast cancer include:

Age: Whether you’re a man or a woman, you’re more likely to get breast cancer as you get older. The average age for a man to get diagnosed is 68. However, you can get breast cancer at any age.

Genes: Breast cancer runs in families. If your father, brother, or other close relatives were diagnosed, you may also be at risk. Certain genes increase your likelihood of getting this cancer — including the BRCA1 and BRCA2 genes. These genes code for proteins that prevent breast cells from growing out of control. Both men and women who inherit the BRCA1 or BRCA2 gene mutations are at increased risk for breast cancer, although their risk is still small. Your lifetime risk of breast cancer is about 1 percent if you have the BRCA1 gene, and 6 percent if you have the BRCA2 gene.

Weight gain: Fat tissue releases the female hormone estrogen. Estrogen stimulates breast cancer growth. The more overweight you are, the more of this hormone you produce.

Hormone exposure: You’re at higher risk for breast cancer if you take hormone-based drugs (for example, to treat prostate cancer), or if you were exposed to estrogen through food, pesticide, or other products.

Klinefelter syndrome: This condition causes men to be born with an extra copy of the X chromosome. Normally, men have one X and one Y chromosome (XY). In Klinefelter syndrome, they have two copies of the X chromosome in addition to the Y chromosome (XXY). Men with this condition have smaller than normal testicles. They make less testosterone and more estrogen than usual. Men with Klinefelter syndrome are at greater risk for breast cancer.

Heavy alcohol use: Drinking a lot of alcohol can cause estrogen levels in your blood to rise.

Liver disease: Cirrhosis and other diseases that damage the liver can reduce the amount of male hormones and increase the amount of estrogen in your body.

Surgery to your testicles: Damage to your testicles can increase your risk for breast cancer.

Radiation exposure: Radiation is linked to breast cancer. If you received radiation to the chest to treat another type of cancer, you could be at greater risk for breast cancer.

Learn about karyotyping, a lab test that helps examine your chromosomes »

Breast cancer in men is rare, but it can still happen. Men make up less than 1 percent of all breast cancer cases. A man’s risk of getting breast cancer during his lifetime is about 1 in 1,000.

The disease is much less common in men because their breast ducts — where the cancer starts — are less well-developed than women’s. Men also have lower levels of estrogen, the hormone that fuels breast cancer growth.

Breast cancer can spread to other parts of the body, which makes it more serious. Male breast cancer is just as serious as female breast cancer.

Your outlook depends on what type of cancer you have and how quickly you’re diagnosed. Your odds of being cured are highest if you catch the cancer early. The five-year relative survival rate for a man with stage 0 or stage 1 breast cancer is 100 percent. That’s why it’s important to check your breasts regularly, and alert your doctor right away if you spot any symptoms of breast cancer.

Learn more: Breast cancer staging »

Many risks for breast cancer — like family history and age — are out of your control. But there are a few risk factors you can control, including obesity.

Here are some tips to help lower your odds of getting breast cancer:

  • Keep your weight within a healthy range. Obesity can shift the hormone balance in your body, making you more likely to get breast cancer. If you’re overweight, talk to your doctor and a dietitian about making changes to your eating and exercise plan.
  • Exercise on most days of the week. A lack of physical activity can alter your hormone levels, making you more susceptible to cancer.
  • Avoid or limit alcohol. Having two or more alcohol drinks daily has been linked to an increased risk for breast cancer in women. Even though the link isn’t as clear in men, it’s still worth cutting back.

If male breast cancer runs in your family, you may not be able to prevent it. However, you can catch it early by knowing your risk. Talk to a genetic counselor about getting tested for BRCA1, BRCA2, and other genes.

Find out: How accurate are those genetic tests you can take at home? »