Rochester, Minnesota - Lymphedema is most commonly caused by the removal of or damage to your lymph nodes as a part of cancer treatment. It results from a blockage in your lymphatic system, which is part of your immune system. The blockage prevents lymph fluid from draining well, and the fluid buildup leads to swelling.

Mayo Clinic surgeon Dr. Sarah McLaughlin says, "It's one of the most feared complications of breast cancer treatment. The swelling of the arm is uncomfortable and a constant reminder of the cancer treatment." However, while many women are are advised not to exercise after treatment, it may actually help prevent lymphedema and lessen symptoms.