Breast Cancer and Lymph Node Removal

If you’ve been diagnosed with invasive breast cancer, you may be wondering why your doctors are talking about removing some of your lymph nodes. Lymph node surgery is done because cancer cells that move beyond the breast often get trapped by nearby lymph nodes in the underarm.

Having cancer in the lymph nodes is associated with an increased risk of having cancer cells that spread to other parts of your body. You may have a few lymph nodes removed as part of surgery to remove breast cancer or as a separate surgery called a lymphadenectomy. This can help doctors determine the stage of the cancer and treatment plan.

Your lymph nodes are part of your immune system. Lymph nodes are connected through vessels throughout the body. The lymph nodes and lymph vessels help remove bacteria, viruses, and other waste traveling through lymph fluid. There are hundreds of lymph nodes in the body, including in the neck, armpit, chest, belly, and groin.

If cancer spreads beyond the breast, the likely first stop will be to the sentinel lymph nodes in the underarm (axilla) area. A surgeon locates and removes up to three sentinel lymph nodes as part of a sentinel lymph node biopsy. These nodes are then sent to a pathologist who checks them for cancer. 

If the sentinel nodes don’t show any cancer, it’s likely that no other axillary lymph nodes contain cancer. Treatment decisions can be made with this important information in mind. If a sentinel node contains cancer, you may need additional treatment.

If cancer is detected in sentinel nodes in your underarm, your doctor may recommend that you have more lymph nodes removed for testing. This is called an axillary lymph node dissection and can involve the removal of 10 or more lymph nodes. 

The greater the number of axillary nodes that have cancer cells, the greater the risk that breast cancer has spread to other areas of the body. Knowing the number of axillary nodes with cancer cells that you have will help doctors determine whether cancer may have spread to other parts of your body. This will help decide the next steps in your treatment.

It will take time to recover from a lymph node removal operation. How quickly you heal will depend on your body, how many lymph nodes you had removed, and other breast cancer surgeries you may have had. Side effects of lymph node removal can include lymphedema, infection, bleeding, and numbness. Be sure to talk to your healthcare team about any side effects that are bothering you.

— Last updated on August 7, 2025 at 5:06 PM