It has been estimated that 12% of women in the United States will develop breast cancer during their lifetimes. Women whose breast cancer has spread to nearby lymph nodes often require surgical removal or irradiation of the affected nodes; however, these treatments damage the lymphatic system and may cause lymphedema, swelling of the adjacent arm due to accumulation of lymph fluid. This is a serious complication that affects 8% to 56% of breast cancer survivors. In addition to increasing the likelihood of infection, lymphedema impairs quality of life cosmetically and physically with symptoms such as arm tightness, heaviness, weakness, and loss of sensation. The risk of lymphedema varies depending on the number of lymph nodes removed and the location and amount of radiation received in addition to surgery.