ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Breast Cancer in Men. To see other pages, use the menu on the side of your screen. Think of that menu as a roadmap to this full guide.
Breast cancer in men is rare, accounting for less than 1% of all breast cancers. Although breast cancer in men occurs less frequently than breast cancer in women, the diseases are similar in many ways.
About the breast
The breast is mostly made up of fatty tissue. Within this tissue is a network of lobes, which are made up of tiny, tube-like structures called lobules that contain milk glands. Tiny ducts connect the glands, lobules, and lobes to the nipple, located in the middle of the areola, which is the darker area that surrounds the nipple of the breast. Blood and lymph vessels run throughout the breast; blood nourishes the cells, and the lymph system drains bodily waste products. The lymph vessels connect to lymph nodes, the tiny, bean-shaped organs that help fight infection.
About breast cancer
Cancer begins when normal cells in the breast change and grow uncontrollably, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can spread to other parts of the body. A benign tumor means the tumor will not spread.
Breast cancer spreads when breast cancer cells move to other parts of the body through the blood vessels and/or lymph vessels. This is called metastasis. Breast cancer most commonly spreads to the regional lymph nodes. The lymph nodes can be located under the arm, called the axillary lymph nodes, under the sternum or breast bone, called the mediastinal lymph nodes, or just above the collarbone, called the supraclavicular lymph nodes. When it spreads further through the body, it most commonly spreads to the bones, lungs, and liver. Less commonly, breast cancer may spread to the brain. The cancer can also come back after treatment locally in the skin, in the same breast, other tissues of the chest, or elsewhere in the body.
Types of breast cancer
The main types of breast cancer are the same for men and women. Most breast cancers start in the ducts or lobes. Almost 75% of all breast cancers begin in the cells lining the milk ducts and are called ductal carcinomas. Approximately 25% breast cancers in men are lobular carcinoma, which begins in the lobules.
A type of breast cancer that has spread outside of the duct and into the surrounding tissue is called invasive or infiltrating carcinoma. The majority of men with breast cancer have infiltrating ductal carcinomas (IDC).
Disease that has not spread is called in situ, meaning "in place." Ductal carcinoma in situ (DCIS) is the most common type of in situ breast cancer, but it is uncommon in men.
Other types of breast cancer include Paget's disease of the nipple, which begins in the ducts but spreads to the skin of the nipple. Paget’s disease is more common in men than in women. Another type is inflammatory breast cancer , which makes up about 1% to 5% of all breast cancers; this type is rare in men. Less common subtypes of breast cancer include medullary, mucinous, tubular, or papillary.
Breast cancer in men is found the same way as breast cancer in women is—through self-examination, clinical examination, or through an x-ray of the breast called a mammogram. Changes in the breast may be easier to detect because, in general, men have less breast tissue. However, the awareness of breast cancer in men is much lower than it is in women; therefore, men may not perform regular breast self-examinations or talk with their doctor about the disease.
Looking for More of an Overview?
If you would like additional introductory information, explore these related items. Please note these links take you to other sections on Cancer.Net:
- ASCO Answers Fact Sheet : Read a one-page fact sheet (available as a PDF) that offers an easy-to-print introduction to breast cancer.
- ASCO Answers Guide : This 52-page booklet (available as a PDF) helps newly diagnosed patients better understand their disease and treatment options, as well as keep track of the specifics of their individual cancer care plan.
- Cancer.Net Patient Education Video : View a short video led by an ASCO expert in breast cancer that provides basic information and areas of research.
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