Lymphedema is a condition that can cause significant swelling of the upper and lower extremities due to the build-up of excess lymph fluid. This can occur when the lymphatic system, which is responsible for draining excess fluid from the body and is a key component of the immune system, is damaged or altered. In breast cancer patients, this can occur after surgery, such as removal or biopsy of the lymph nodes, and/or radiation therapy. It is estimated that six percent to 40 percent of patients with breast cancer develop lymphedema, and that it often occurs within the first two years after surgery. For some cancer survivors and others at risk, a low level lymphedema can occur 10 years to 15 years following the initial primary treatment and develop into a condition that has a serious impact on overall health and quality of life.