Lymphedema of the arm is an important, under-recognized, and under-treated complication of successful surgical and radiotherapeutic treatment of breast cancer. As a result of advances in early detection and effective adjuvant therapies, many women diagnosed with breast cancer today can expect survival that is similar to age-matched women without breast cancer. Nevertheless, this source of substantial physical and psychological morbidity has not attracted sufficient attention from industry or the scientific research community to result in either effective risk stratification or the availability highly effective therapeutic interventions.