Breast cancer treatment-related lymphedema (swelling) is an incurable, chronic condition experienced by a significant percentage of breast cancer survivors. It has many associated symptoms, negatively impacts quality of life (QOL), and increases health care costs. As with other chronic diseases such as diabetes, life-long self- care is required. Less than half of breast cancer survivors complete self-care as directed. Lack of perceived results from self-care and feeling unable to manage the condition are contributing factors. No objective measurement mechanism exists that can easily be used to self-monitor arm volume, a key self-care outcome. Those with lymphedema are forced to rely on visual recognition of increasing volume to know if their self-care is effective and when to seek treatment. Timely recognition of worsening swelling is believed to result in better patient outcomes; however, substantial volume increases occur before observable changes are noted and this window of opportunity is often missed. Many with lymphedema seek care only when they have developed infection in the swollen limb. The inability to objectively monitor arm volume on a regular basis likely results in discomfort, poorer QOL, and increased health care costs. The National Cancer Institute aims to improve QOL for cancer survivors. The National Institute of Nursing Research states that self-management and symptom management are key areas in the improvement of QOL. In keeping with these Institutes' aims, the broad, long- term objective of this application is to develop a method for monitoring arm lymphedema that can be used at home to improve lymphedema self-management and patient outcomes. To accomplish this, we will conduct a two-phase, translational pilot study to explore the use of a hand-held bioelectrical impedance device as an arm volume self-measurement method. Participants in previous studies have repeatedly expressed the desire to use these devices at home to monitor their arms like diabetics monitor their blood sugar. Phase 1 aims to develop a bioelectrical impedance self-measurement protocol. Phase 2 aims to compare self-care activities and health and economic outcomes between breast cancer survivors with lymphedema following the self- monitoring protocol and breast cancer survivors with lymphedema not on protocol. Healthy volunteers and individuals with lymphedema will be in Phase 1 (protocol development). This will take place in laboratory and home settings. The protocol will be field-tested by breast cancer survivors with lymphedema in Phase 2 (a two group randomized clinical trial). One group will self-measure with impedance at home for three months, weekly record self-care activities, and will complete follow-up assessments 30 days after exit from the study. The other group will mirror Group 1 except for impedance measurements and will complete all assessments at the same time points. Demographic and medical history data will be collected from all participants. In Phase 2, baseline and monthly assessments will be collected. Findings from this study will be used to determine if bioelectrical impedance warrants further research as a self-measurement method. PUBLIC HEALTH RELEVANCE: Breast cancer survivors often suffer permanent swelling in arms post-treatment, and self-care is crucial to keep swelling somewhat under control. A means to perform arm measurement is needed to evaluate effective self- care and discern when to seek medical treatment. This research will test a self-measurement device.