The Lymph Nodes

Are there breast cancer cells in your lymph nodes?

Having cancer cells in the lymph nodes under your arm is associated with an increased risk of the cancer spreading.

Lymph nodes are filters along the lymph fluid channels. Lymph fluid leaves the breast and goes back into the bloodstream. The lymph nodes try to catch and trap cancer cells before they reach other parts of the body.

When lymph nodes are free or "clear" of cancer, the test results are called "negative." If lymph nodes have some cancer cells in them, they are called "positive."

How many lymph nodes are involved?

The more lymph nodes have cancer cells in them, the more serious the cancer might be. For this reason, doctors use the number of involved lymph nodes to help make treatment decisions.

Doctors also look at the amount of cancer in the lymph nodes.

You may see these words describing how much cancer is in each lymph node:

• Microscopic: Only a few cancer cells are in the node. A microscope is needed to find them.
• Gross: There is a lot of cancer in the node. You can see or feel the cancer without a microscope.
• Extracapsular extension: Cancer has spread outside the wall of the node.