Understanding premature discontinuation of aromatase inhibitor (AI) therapy in postmenopausal breast cancer survivors.

Abstract

6073 Background: Suboptimal adherence and premature discontinuation of AIs in breast cancer survivors (BCS) compromise treatment outcomes. While several studies report suboptimal adherence to AIs, few have examined rates and predictors of premature discontinuation, and none have evaluated patient-reported reasons for stopping early. Understanding reasons for prematurely stopping AIs are important as these offer opportunities for preventative intervention. Methods: We conducted a cross-sectional survey of 490 postmenopausal non-metastatic BCS prescribed AIs at an outpatient oncology clinic. The primary outcome was premature discontinuation of AIs, defined as stopping prior to end of prescribed therapy (self-report confirmed by chart review). Predictors included sociodemographic factors, health variables, treatment variables (e.g., prior tamoxifen, chemotherapy), and prior communication with a health care provider about difficulty taking AI therapy. Patients also self-reported reasons for stopping AIs. Results: 32 BCS (7%) had prematurely discontinued AI therapy after a mean of 15.7 months (range, 1 to 55 months). In univariate analyses, previously taking Tamoxifen, having inflammatory conditions (e.g., rheumatoid arthritis), never having been asked about difficulty taking AIs, and being married were significant predictors of stopping AIs early (all p ≤ 0.05). In multivariate analysis all remained significant (p ≤ 0.05). Patients reported side effects as the most frequent reason for stopping AIs early, with 17 (53%) reporting joint pain, 5 (16%) effects on bone, and 12 (32%) reporting other side effects, such as hot flashes and cognitive effects. Conclusions: BCS who prematurely stopped AIs did so an average of just over a year after treatment initiation. This is the first study to examine self-reported reasons for stopping AIs. These data suggest a profile of BCS at high risk for early discontinuation, and highlight the importance of provider communication and assessment and management of symptoms, including joint pain, in designing supportive interventions for these women. No significant financial relationships to disclose.