Male breast cancer is a rare but real disease that affects men across the globe. While most people associate breast cancer with women, men also have breast tissue that can develop cancer, and understanding this condition is crucial for early detection and successful treatment.
How Common Is Male Breast Cancer?
Male breast cancer is an uncommon condition that accounts for less than one percent of all breast cancer cases diagnosed. In the United States, approximately 2,800 men receive a diagnosis of breast cancer each year, and around 510 men die from the disease annually. To put this in perspective, about one out of every 100 breast cancers diagnosed in the United States is found in a man. The lifetime risk for an American man to develop breast cancer is approximately 1 in 1,000, compared to 1 in 8 for women.[5][6]
The disease typically affects older men, with most cases occurring between the ages of 60 and 70 years. However, it’s important to recognize that male breast cancer can occur at any age, and younger men should not dismiss concerning symptoms simply because the condition is more common in older age groups.[7][8]
From 2018 to 2022, the breast cancer incidence rate in men increased slightly, by less than one percent per year. While the rates of new cases and deaths from breast cancer are much lower among men than among women, the survival rates for men are similar to those for women when the cancer is detected at the same stage. Unfortunately, men are often diagnosed at a later stage than women, which can affect their overall prognosis.[5][12]
Male breast cancer incidence rates in the United States also vary by race and ethnicity. Non-Hispanic Black men have the highest breast cancer incidence rate overall, while non-Hispanic Asian and Pacific Islander men have the lowest rates.[5]
What Causes Breast Cancer in Men?
Male breast cancer develops when the DNA inside breast cells changes or mutates. These mutated cells begin multiplying rapidly and don’t die off as normal cells do. Over time, the cancer cells accumulate and form masses called tumors, which are abnormal growths of tissue. Parts of the tumor may break off and spread to other body parts through the lymphatic system, which is a network of vessels that carry fluid throughout the body, or through the bloodstream. When cancer spreads beyond its original location, it is called metastatic cancer.[3][13]
Scientists continue to research what causes healthy breast cells to transform into cancer cells in the first place. While the exact trigger remains unclear, researchers have identified several factors that appear to play a role in the development of male breast cancer. Understanding these causes helps medical professionals better identify who might be at higher risk and develop strategies for prevention and early detection.
Risk Factors That Increase the Likelihood of Male Breast Cancer
Several factors can increase a man’s chance of developing breast cancer, though having one or more risk factors doesn’t mean that cancer will definitely develop. The most significant risk factor is advancing age, as most men diagnosed with breast cancer are in their 60s or older.[2][3]
Family history plays an important role in breast cancer risk for men. If a man has a parent, sibling, or child with breast or ovarian cancer, his risk of developing breast cancer is higher. This familial connection exists because certain breast cancer genes can be passed down through families. Studies have shown that having an affected sibling or parent of either gender may increase the risk of breast cancer in both male and female family members.[2][10]
Genetic mutations represent another significant risk factor. Inherited changes in certain genes, particularly BRCA1 and BRCA2 (which stands for BReast CAncer genes), substantially increase breast cancer risk in men. While it is rare for a male to carry a BRCA mutation, those who do face elevated risks. Men with a BRCA2 mutation have about a six percent increased risk of developing breast cancer, and those with BRCA1 have about a four percent risk. By age 70, men with BRCA1 pathogenic variants have an estimated cumulative breast cancer risk of 1.2 percent, while those with BRCA2 pathogenic variants have a 6.8 percent risk.[2][10][12]
Less common genetic mutations that increase male breast cancer risk occur in conditions like Cowden syndrome, which involves the PTEN tumor suppressor gene, Li-Fraumeni syndrome, which involves the TP53 gene, and Lynch syndrome, which involves mismatch repair genes.[3][10][12]
High estrogen levels in the body also contribute to increased breast cancer risk. Estrogen is a hormone that helps develop and maintain female sex characteristics, but men also produce small amounts of it. Certain conditions can raise estrogen levels or lower androgen levels (hormones that help develop and maintain male sex characteristics) in men. These conditions include cirrhosis of the liver, which causes scarring of liver tissue, and obesity, which can lead to higher estrogen production. Klinefelter syndrome, a rare genetic condition in which a male has an extra X chromosome, can lead to the body making higher levels of estrogen and lower levels of androgens, thereby increasing breast cancer risk.[2][3][7]
Past medical treatments can also elevate risk. Men who have had radiation therapy to the chest area have a higher risk of developing breast cancer later in life. Additionally, drugs containing estrogen, which were used in the past to treat prostate cancer, increase men’s breast cancer risk. Certain conditions that affect the testicles, which produce androgens, can also increase breast cancer risk.[2][7]
Being overweight or having obesity increases breast cancer risk in older men. Extra body fat can lead to higher estrogen levels, which in turn can promote the development of breast cancer.[2]
Recognizing the Signs and Symptoms of Male Breast Cancer
The most common sign of male breast cancer is a firm, painless lump in one of the breasts, usually located behind the nipple. Because men typically have less breast tissue than women, lumps may be easier to feel. However, because breast cancer is so rare in men, it can be easy to dismiss a lump as no big deal, which can lead to delays in seeking medical attention.[1][3][13]
Other signs and symptoms of male breast cancer include a lump or swelling in the armpit, which may indicate that cancer has spread to the lymph nodes. Changes to the skin covering the chest, such as dimpling, puckering, redness, flaky or scaly patches, or changes in skin color, should also raise concern. The skin may take on a dimpled or pitted appearance, similar to the skin of an orange, a condition known as peau d’orange.[1][2][3]
Changes to the nipple are another important warning sign. These changes can include the nipple turning inward, a condition called an inverted nipple, as well as scaling or changes in the color of the nipple skin. Clear or bloody discharge from the nipple, or pain or tenderness in the chest or underarm area, may also occur.[1][2][3]
It’s important to note that these symptoms can also occur with other conditions that are not cancer. However, if you experience any of these symptoms or notice any changes in your breast area, you should see your doctor right away. Early detection is crucial for successful treatment outcomes, and men should not hesitate to seek medical evaluation for any concerning symptoms.[2]
Prevention Strategies and Risk Reduction
While not all cases of male breast cancer can be prevented, there are steps men can take to reduce their risk or detect the disease early when it is most treatable. Understanding your family history is one of the most important prevention strategies. If several members of your family have had breast or ovarian cancer, or if one of your family members has a known BRCA1 or BRCA2 mutation, it’s crucial to share this information with your doctor.[2]
Your doctor may refer you for genetic counseling, where a specialist can assess your personal and family history to determine if genetic testing is appropriate. In men, mutations in the BRCA1 and BRCA2 genes can increase not only the risk of breast cancer but also the risk of high-grade prostate cancer and pancreatic cancer. If genetic testing shows that you have a BRCA1 or BRCA2 gene mutation, your doctor will explain what screening and monitoring steps you should take to detect cancer early if it develops.[2]
Maintaining a healthy weight is another important prevention strategy, particularly for older men. Since obesity is associated with higher estrogen levels and increased breast cancer risk, regular physical activity and a balanced diet can help reduce risk. Managing liver disease and avoiding excessive alcohol consumption can also help, as liver health affects hormone levels in the body.[2]
Men should also be aware of their breast tissue and report any changes to their doctor promptly. Performing regular breast self-exams can help you become familiar with what is normal for your body, making it easier to notice any changes. If you have any of the risk factors mentioned above, discuss with your doctor whether any specific screening or monitoring is recommended for you.[2]
How Breast Cancer Affects the Male Body
To understand how breast cancer develops in men, it’s helpful to know the basic anatomy of the male breast. Boys and girls begin life with similar breast tissue, but their breasts develop differently during puberty. At puberty, high testosterone levels and low estrogen levels stop breast development in men. Men have some milk ducts, which are tubes that would normally connect glands to the nipple, but these ducts remain undeveloped. Lobules, which are the glands that produce milk in women, are most often absent or very few in men.[5][7]
Despite having less breast tissue than women, men still have enough tissue for cancer to develop. The male breast contains the nipple and areola, which is the darker area of skin surrounding the nipple, on the outside. Inside the breast, there are lymph nodes, fatty tissue, and ducts. Cancer most commonly forms in the ducts.[2][7]
The most common type of male breast cancer is invasive ductal carcinoma, which accounts for up to nine out of ten cases. With this type, cancer starts in the breast ducts and then spreads beyond the ducts to other parts of the breast tissue. Ductal carcinoma in situ, abbreviated as DCIS, is less common. With DCIS, abnormal cells are found in the lining of a duct but have not spread beyond it. This is sometimes called intraductal carcinoma.[2][3][7]
Invasive lobular carcinoma is uncommon in men because males have few, if any, lobules. With this type, cancer forms in the lobules and can spread to other parts of the body. Other rare types of male breast cancer include inflammatory breast cancer, in which the breast looks red and swollen and feels warm, and Paget disease of the nipple, where a tumor has grown from ducts beneath the nipple onto the surface of the nipple.[3][7]
Most male breast cancers have receptors on their cells that cause them to grow in response to specific hormones. A receptor works like a lock that fits a specific key, which in this case is a hormone. When the hormone attaches to the receptor, the cancer cells divide and multiply. Most male breast cancers have receptors that cause cancer cells to grow in response to progesterone and estrogen. The most common form of breast cancer in men is estrogen receptor-positive (ER+) invasive ductal carcinoma.[3][13]
When cancer cells remain localized in the breast, they can often be treated effectively with surgery and other therapies. However, if the cancer spreads, it becomes more difficult to treat. Cancer can spread through the lymphatic system, which is why lymph nodes in the armpit are often examined during diagnosis. Cancer can also spread through the bloodstream to distant parts of the body, such as the bones, liver, lungs, or brain. This spreading process is called metastasis, and cancer that has spread is known as metastatic cancer or stage 4 breast cancer.[3][13]
