Relationship between genetic makeup and drug tolerance

This study is for patients with breast cancer at treatment time point of using a medication type called aromatase inhibitors. The drug anastrozole will be used. The effects that this drug has on the patient and whether genetics plays a part in how this drug effects patients will be studied. Muscle and joint aches, AIMSS(aromatase inhibitor-associated musculoskeletal syndrome), specifically will be studied. This study will also monitor the effects of hormone therapy on the patient's quality of life and willingness to continue treatment.