Breast cancer

Breast cancer is cancer that develops in breast cells. Typically, the cancer forms in either the lobules or the ducts of the breast. Lobules are the glands that produce milk, and ducts are the pathways that bring the milk from the glands to the nipple. Cancer can also occur in the fatty tissue or the fibrous connective tissue within your breast.

• In 2019, an estimated 268,600 new cases of invasive breast cancer will be diagnosed in women in the U.S. as well as 62,930 new cases of non-invasive (in situ) breast cancer.
• 62% of breast cancer cases are diagnosed at a localized stage, for which the 5-year survival rate is 99%.
• This year, an estimated 41,760 women will die from breast cancer in the U.S.
• Although rare, men get breast cancer too. The lifetime risk for U.S. men is about 1 in 1,000.

The uncontrolled cancer cells often invade other healthy breast tissue and can travel to the lymph nodes under the arms. The lymph nodes are a primary pathway that help the cancer cells move to other parts of the body. See pictures and learn more about the structure of the breast.

Doctors know that breast cancer occurs when some breast cells begin to grow abnormally. These cells divide more rapidly than healthy cells do and continue to accumulate, forming a lump or mass. Cells may spread (metastasize) through your breast to your lymph nodes or to other parts of your body.

• Mammogram. The most common way to see below the surface of your breast is with an imaging test called a mammogram. Many women aged 40 and older get annual mammograms to check for breast cancer. If your doctor suspects you may have a tumor or suspicious spot, they will also request a mammogram. If an abnormal area is seen on your mammogram, your doctor may request additional tests.
• Ultrasound. A breast ultrasound uses sound waves to create a picture of the tissues deep in your breast. An ultrasound can help your doctor distinguish between a solid mass, such as a tumor, and a benign cyst.

• a breast lump or tissue thickening that feels different than surrounding tissue and has developed recently
• breast pain
• red, pitted skin over your entire breast
• swelling in all or part of your breast
• a nipple discharge other than breast milk
• bloody discharge from your nipple
• peeling, scaling, or flaking of skin on your nipple or breast
• a sudden, unexplained change in the shape or size of your breast
• inverted nipple
• changes to the appearance of the skin on your breasts
• a lump or swelling under your arm

To start, your doctor will determine your cancer’s size, stage, and grade (how likely it is to grow and spread). After that, you can discuss your treatment options. Surgery is the most common treatment for breast cancer. Many women have additional treatments, such as chemotherapy, targeted therapy, radiation, or hormone therapy.