Did You Know 1 in 8 Women Will Develop Breast Cancer?

What Is Breast Cancer?

Breast cancer is the most common form of cancer found in women, and is caused by the uncontrolled growth of malignant (cancerous) breast cells. (Breast cancer can also be found in men, though far less frequently.)

A breast consists of glandular tissue called lobes. These lobes are divided into lobules, which can produce milk.

Milk is carried from the lobules to the nipple by small ducts. All of this is surrounded by fatty and connective tissue, as well as blood and lymph vessels.

Breast cancer can start anywhere in the breast tissue, but starts most commonly in glandular tissue like ducts and lobules.

The cancer cells may eventually form a tumor, or invade nearby tissue, such as the chest wall or lymph glands.

Most breast cancers are carcinomas--malignant tumors that grow out of the surface or lining of the glandular tissue of the breast.

Other very rare types of breast cancer are formed in the surrounding and supporting tissues, and are referred to as sarcomas, acinar tumors, or lymphomas.

Breast cancer is classified by how invasive it is.

"In situ" cancers are localized to the breast and are the easiest to treat and cure. "Invasive" cancers have begun to spread beyond the primary site to adjacent tissue or distant sites in the body, and require more intensive treatments.

In Situ Breast Cancers Include:

  • Ductal carcinoma in situ (DCIS) develops in the milk ducts, is commonly found on mammograms, and has a high cure rate.
  • Lobular carcinoma in situ (LCIS) develops in the lobules. It is not really a "cancer," and is considered an incidental finding that increases future risk for developing the disease. It will be monitored by your provider for growth and development on an ongoing basis.

Invasive Breast Cancers Include:

  • Ductal carcinoma develops in the milk ducts, is the most common form of breast cancer, and it accounts for 80% of breast cancer cases.
  • Lobular carcinoma originates in the milk-producing lobules of the breast. It can spread to the fatty tissue and other parts of the body.
  • Medullary, mucinous, and tubular carcinomas are 3 relatively slower-growing types of breast cancer. They are named based on their appearance under a microscope.
  • Inflammatory breast cancer is relatively uncommon, but is fast growing and difficult to treat.Cancer cells invade the lymphatic vessels of the skin and can be very extensive. It is very likely to spread to the local lymph nodes and require extensive coordinated treatment.