Altering Lipids for Tolerance of Aromatase Inhibitor Therapy

Inclusion Criteria * Female subject aged ≥ 18 years who are postmenopausal according to standard clinical criteria or who will have been receiving LHRH agonist therapy for at least 28 days prior to AI initiation. * Stage 0-3 estrogen receptor positive (≥1%) and/or progesterone receptor positive (≥1%) breast cancer, or patients at high risk of developing breast cancer who are planning to initiate AI therapy for chemoprevention. * Planned initiation of aromatase inhibitor therapy (anastrozole, exemestane, or letrozole) for adjuvant treatment of breast cancer or for chemoprevention up to 30 days following baseline visit (ok to initiate screening up to 2 months before planned baseline visit). Concurrent LHRH agonist, anti-HER2 directed therapy (e.g., trastuzumab, pertuzumab, ado-trastuzumab emtansine), and/or CDK4/6 inhibitor therapy (e.g., palbociclib, ribociclib, abemaciclib) is permitted. Prior tamoxifen and/or toremifene is permitted. * Completion of surgery (mastectomy or lumpectomy/partial mastectomy) for treatment of breast cancer. Completion of axillary surgery as indicated (not required). For patients at high risk of breast cancer who have not been diagnosed with breast cancer, no surgery is required. * Completion of chemotherapy, if indicated. Concurrent use of radiation therapy, LHRHa therapy, anti-HER2 therapy, PARP inhibitor, and CDK4/6 inhibitor therapy is permitted. Prior tamoxifen is permitted. * Agree to avoid taking omega-3 fatty acid supplements from sources o…