LYMPHEDEMA refers to swelling that generally occurs in one of your arms, legs, head, neck or chest. It is most often caused by a blockage in your lymphatic system, an important part of your immune and circulatory systems. The blockage prevents lymph fluid from draining well, and as the fluid builds up, the swelling continues. Lymphedema is most commonly caused by the removal of or damage to your lymph nodes as a part of radiation treatment. There’s no cure for lymphedema, but it can be controlled.