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. 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 often occur before observable changes are noted and this window of opportunity is missed. Many with lymphedema only seek care when they have developed infection in the swollen limb.