Abstract B10: Side effects associated with aromatase inhibitor treatment among breast cancer patients

Introduction: Aromatase inhibitors (AIs), a first-line hormonal treatment for estrogen-receptor positive breast cancer, have clear benefit in reducing recurrence risk and increasing survival. Musculoskeletal symptoms are a well-known side effect of treatment, but the spectrum of other side effects is less well characterized. Side effects of AIs may impact quality of life and potentially medical adherence. The purpose of this study was to examine whether AI treatment was associated with side effects other than musculoskeletal symptoms. Methods: A cohort study of 100 breast cancer patients initiating AI treatment (“cases”) and 200 women without a history of cancer (“controls”) was conducted. Questionnaire data on symptoms were collected prior to AI treatment for the cases and at the start of the study for the controls (baseline). All participants were followed for six months, with questionnaires being administered at three months and at the end of follow-up. Data on the frequency at which a number of symptoms were experienced was collected. The prevalence of each symptom at baseline among all cases and in the subgroup of cases who had not received chemotherapy was compared to controls. In addition, new onset of each specific symptom during the six month follow-up among cases compared to controls was examined. Analyses were conducted using logistic regression, and results are reported as age-adjusted odds ratios (OR) comparing cases to controls. Results: At baseline, cases were more likely than the controls to have experienced hot flashes, decreased appetite, fatigue, fever, breast sensitivity, swelling of hands and feet, difficulty concentrating, and tendency to take naps. These differences remained when limiting the sample of cases to those who had not received chemotherapy. The initiation of AI treatment was significantly associated the new onset of the following symptoms during the follow-up period: hot flashes (OR 5.13; p Conclusions: AI treatment results in an extreme estrogen-deficient state and is associated with the onset of a number of symptoms that occur much more frequently compared to postmenopausal women of similar age without a history of cancer. These symptoms may impact adherence. This study was funded by Susan G. Komen for the Cure, AstraZeneca, and the National Cancer Institute (CA132147). Citation Information: Cancer Prev Res 2010;3(12 Suppl):B10.