Breast cancer in men is rare, but men do develop it. Male breast cancer accounts for less than 1% of all breast cancer cases. Other than the incidence rate, male breast cancer is similar to breast cancer in women.

All breast cancer begins when normal cells in the breast change and begin to grow uncontrollably, eventually forming a tumor. A tumor can be benign (noncancerous) or malignant (cancerous).

Breast tissue is composed of mostly fatty tissue. Growing within the breast tissue there is a network of tube-like structures called lobules. In the lobules are the milk glands (yes, men too have milk glands). There is also a system of tiny ducts that connect the glands, lobules, and lobes to the areola (the dark area surrounding the nipple). The breast also contains blood and lymph vessels that both nourishes the breast cells and drains bodily waste. The lymph vessels are connected to bean shaped organs (lymph nodes) which fight infections.

Most breast cancer cases start in either the ducts or lobes of the breast. Almost 75% of all breast cancers are called ductal carcinomas and begin in the cells that line the milk ducts. However, approximately 25% of male breast cancers begin in the lobules (lobular carcinoma).

Invasive or infiltrating carcinomas of the breast are cancers that have spread outside of the duct and moved into the surrounding tissue. The majority of male breast cancer cases are infiltrating ductal carcinomas (IDC).

When the cancer has not spread is called insitu, meaning it has stayed “in place.” Ductal carcinoma insitu (DCIS) is the most common type of insitu breast cancer in women, but it is uncommon in men.

Inflammatory breast cancer makes up about 1% to 5% of all breast cancers. Paget’s disease of the nipple, which is more common in men than women, begins in the ducts and spreads to the skin of the nipple. There are other, less common subtypes of breast cancer including medullary, mucinous, tubular, or papillary.

Breast cancer, like all other cancer, begins as a single, genetically abnormal cell. As this cell divides and then continues to divide, it eventually becomes a tumor and develops its own blood supply. This blood supply is required in order to nourish the tumor allowing it to continued its growth. At some point, the cancer may become metastatic with some cells breaking off from the primary tumor and move to other parts of the body.

As with all other types of cancers, breast cancer spreads when the cancerous cells move to other locations in the body and create their own tumors and blood supply. Most researchers beleive that the movement of these cancerous cells is through the blood vessels and/or lymph vessels. One of the more common sites for an initial spread is the regional (nearby) lymph nodes. The lymph nodes can be axillary (located under the arm), mediastinal (under the sternum or breast bone), or supraclavicular (located just above the collarbone). Other common sites of distant metastasis are the bones, lungs, and liver. Less commonly, breast cancer may also spread to the brain. After the cancer has been treated it can still recur locally in the skin, in the same breast (if it was not removed as part of treatment), other tissues of the chest, or elsewhere in the body.

Breast cancer in men is detected the same way as is breast cancer detected in women. Self-examination, clinical examination, and mammography (x-ray of the breast) are the best ways to detect it. Men have an advantage as changes in the breast often are easier to detect because men have less breast tissue. However, the awareness of breast cancer in men is so low that most men do not perform regular breast self-examinations or talk with their doctor about the disease, this can be a recipe for a disaster.

Joel T Nowak, MA, MSW