While breast cancer is commonly seen in women, men can develop the disease too.

Breast cancer is the most common cancer in women worldwide and the second most common cancer overall. While the disease occurs primarily in women, men also have breast tissue and are at risk of developing breast cancer.

While rare, breast cancer occurs in more than 2,600 men each year and approximately 500 men die from the disease each year. About 1 in 833 men will develop breast cancer in their lifetime, compared to 1 in 8 women who will develop breast cancer.

What are the causes of breast cancer in men?

While men who carry a mutation in the BRCA2 gene have in increased risk of developing breast cancer, most breast cancers in men are not caused by inherited factors. Exposure to radiation treatment to the chest, as well as conditions that increase levels of estrogen, such as obesity, are also factors that influence the risk of breast cancer in men.

RELATED: Research Is the Reason I Have Something to Sing About

What are the symptoms of male breast cancer?

According to the Mayo Clinic, signs and symptoms of male breast cancer can include:

  • A painless lump or thickening in your breast tissue
  • Changes to the skin covering your breast, such as dimpling, puckering, redness or scaling
  • Changes to your nipple, such as redness or scaling, or a nipple that begins to turn inward
  • Discharge from your nipple

How is male breast cancer treated?

Most breast cancers in men are estrogen receptor (ER)-positive invasive ductal carcinoma. This is also the most common breast cancer in women. 

Unfortunately, here has been little research in male breast cancer, especially in how best to treat it. Men are often excluded from, or at least not recruited to breast cancer clinical trials, because the disease is so rare in men. As a result, treatment in men is much the same as treatment in women, with anti-hormone drugs such as tamoxifen and chemotherapy. While this trend is changing and more clinical trial protocols are including men, the FDA drafted a guidance statement in August 2019 to bring attention to the need for inclusion of men to breast cancer clinical trials. The sheer lack of numbers of men with breast cancer also makes the disease difficult to study.

Because of a lack of research and also a lack of awareness among men and clinicians, some disparities in breast cancer outcomes in men compared to women have been noted in recent studies.

Work by BCRF researcher, Dr. Fatima Cardoso and the International Male Breast Cancer Program suggests that men are frequently undertreated for breast cancer. Her study of 1482 men with breast cancer reported that men were less likely to get breast conserving surgery for early-stage breast cancers or receive endocrine therapy for ER-positive disease than women with similar breast cancers.

RELATED: BCRF Facebook Live Interview with Dr. Fatima Cardoso

More recently, researchers at the Mayo Clinic analyzed data from more than 10,000 men in the National Cancer Database. Their study, published in the journal Cancer, found that factors such as older age at diagnosis, being African-American, having a high grade/stage tumor at diagnosis and receiving total mastectomy all negatively affected breast cancer outcomes. Those men with a higher economic status, a progesterone receptor-positive breast cancer, and who received radiation, chemotherapy and endocrine therapy had better outcomes.

What's next?

In the final phase of the International Breast Cancer Program, Dr. Cardoso hopes to initiate a clinical trial to test a combination hormone therapy in men with breast cancer. Her team will continue to conduct molecular profiling on the more than 500 tumor samples from the retrospective component of the study.

Additional resources

American Cancer Society: Breast Cancer in Men

Male Breast Cancer Coalition: Patient support and resources

Get the Latest

Sign up for updates on groundbreaking research and stories from the breast cancer community.