Breast cancer

The two most common types of breast cancer are defined by where they start within the breast.

• Ductal carcinoma is cancer that starts in a milk duct.
• Lobular carcinoma is cancer that starts in a milk-producing lobule of the breast.

Cancers also are given names indicating whether or not they have spread. "In situ" cancers are cancers that have not spread to tissues outside the breast duct or lobule. Invasive cancers (also called infiltrating cancers) have spread into surrounding breast tissues and can spread to other parts of the body — which is why early detection is important.

To learn more, see left navigation under “Breast Cancer.”