Surgery for breast cancer includes removal of the breast tumor along with the axillary lymph nodes. The status of these nodes helps clinicians determine prognosis and guides treatment decisions. Unfortunately, a relatively common side effect following axillary lymph node dissection is upper-extremity lymphedema. The purpose of this study is to identify risk factors for lymphedema among women who have had axillary surgery for breast cancer. Specific aims include identifying risk factors for lymphedema and comparing quality of life (QOL) ratings for women who have and do not have lymphedema. A case-control study will be conducted with enrollment of 200 participants. Cases will be identified at their lymphedema consult in the physical therapy centers. Using the oncology registry, controls will include patients who have had breast cancer surgery and have not developed lymphedema. The severity of lymphedema and interference with daily life will be assessed with the Measure of Arm Symptom Survey (MASS), a patient-completed survey, and QOL will be collected with the SF-36. Treatment risk factors including previous surgery, radiotherapy and chemotherapy will be obtained from oncology registry data. This study will determine which factors play a role in lymphedema development.