What is Breast Cancer? 

Breast Cancer is a disease that causes cells in the breast to grow in an unhealthy way. These abnormal cells can spread to lymph nodes and other parts of the body. When cancer cells spread this way, it is called metastasizing. Finding and treating the cancer early helps keep it from spreading.

Where breast cancer starts

The inside of the breast is made up of three main parts: lobules, ducts and connective tissue. Cancer cells can start forming in any of them.

  1. Lobules are glands that produce milk
  2. Ducts are tubes that carry milk to the nipple
  3. Connective tissue holds the parts of the breast together

Kinds of breast cancer

There are several kinds of breast cancer. The type depends on where cancer cells start to grow. Most cancer cells start in the lobules or ducts, so most people get one of these three types of breast cancer:

  • Invasive lobular carcinoma. Cancer cells start in the lobules and spread to other parts of the breast.
  • Invasive ductal carcinoma. Cancer cells start in the ducts and spread to other parts of the breast.
  • Ductal carcinoma in situ. A breast disease that may lead to invasive breast cancer. The cancer cells are only in the lining of the ducts, and have not spread to other tissues in the breast.

Learn more about the different kinds of breast cancer, including the less common types, from the Centers for Disease Control and Prevention (CDC)