How Big Is the Cancer? Has It Spread?

Is it confined to the breast, or are nearby areas involved?

The actual size of a cancer can be measured in several different ways:

• how big it feels during a physical examination
• how big it appears on an X-ray or scan, and
• its measurements under the pathologist's microscope.

Your doctor uses this information—together with the other features of the cancer—to design the best solution to your problem. Many doctors categorize a cancer according to an established breast cancer staging system based on:

• the size of the tumor
• the extent to which the tumor is involved with the skin, muscles, and other tissues next to it
• lymph node involvement.

More on breast cancer staging

Your doctors will also need to find out whether the cancer has spread. The spread of breast cancer is usually referred to in the following ways:

• Local: The cancer is confined within the breast.
• Regional: The lymph nodes, primarily those in the armpit, are involved.
• Distant: The cancer is found in other parts of the body as well.

Sometimes doctors use the term "locally advanced" to refer to large tumors that involve the breast skin, underlying chest structures, changes to the breast's shape, and lymph node enlargement that is visible or that your doctor can feel during an exam.