Aromatase inhibitors are commonly prescribed for treatment of postmenopausal women with breast cancer. These medications can cause side effects in some women, and occasionally they can be quite bothersome. We are doing a study to better understand the side effects of aromatase inhibitors so that we can hopefully treat them better or possibly prevent them. In particular, we are interested in pain and difficulty sleeping. This study is designed to assess the effect of aromatase inhibitors on pain, sleep quality, and fatigue and the interplay of these side effects and their subsequent impact on daily activity. Each participant will fill out a series of questionnaires about pain, sleep quality, and fatigue and will also complete a sleep diary and wear an actigraphy watch for 10 days before starting an aromatase inhibitor and after taking it for 3 months. We hope to learn more about these symptoms so we can better manage medication toxicity in the future.

Inclusion Criteria:

• Female, aged 50 years or older, postmenopausal.
• Patients with histologically proven stage 0-III invasive carcinoma of the breast that is estrogen receptor and/or progesterone receptor positive by immunohistochemical staining, who are planning to start treatment with a standard dose of aromatase inhibitor (AI) therapy.
• Subjects must have undergone surgical resection of their primary tumor, as indicated. The most recent surgery must have been performed at least 4 weeks before the baseline evaluation and no additional surgeries (including reconstructive procedures) should be planned during study participation.
• Cytoxic chemotherapy, if applicable, must have been completed at least 4 weeks before the baseline evaluation.
• Radiation therapy, if applicable, must have been completed at least 2 weeks before baseline evaluation.
• Eastern Cooperative Oncology Group performance status 0-2.
• Ability to operate the accelerometer

Exclusion Criteria:

• Diagnosis of sleep apnea or restless leg syndrome.
• Use of a wheelchair for ambulation most of the time.
• Second or third shift workers or other non-traditional sleep schedules.
• History of medical arthritic disease that could confound or interfere with evaluation of pain or activity level, including but not limited to inflammatory arthritis (rheumatoid arthritis, systemic lupus, spondyloarthropathy, psoriatic arthritis, polymyalgia rheumatica), Parkinson's disease, and cancer involving the bone.
• Serious or unstable medical condition that could likely lead to hospitalization during the course of the study or compromise study participation

University of Michigan Cancer Center