Risk of Anastrozole-related Mood Disturbances and Dizziness among Breast Cancer Patients taking Anastrozole

Background: Anastrozole has been widely utilized in the management of endocrine sensitive post-menopausal breast cancer; however, there is high variability in the adverse reactions associated with its use. Anastrozole-associated mood disturbances and dizziness occur less frequently. However, they can still affect the quality of life of breast cancer patients. The aim of this study was to determine the clinical and demographic factors associated with Anastrozole's adverse events. Materials/Methods: This is a cross-sectional study of oestrogen receptor positive post-menopausal women (n = 97) with stages I to III breast cancer receiving Anastrozole (1mg daily). Multivariate analyses were performed to establish the factors associated with Anastrozole-induced mood disturbance and dizziness. Results: Approximately 20.6% and 13.4% of the subjects experienced mood disturbance and dizziness respectively. Patients who are on Anastrozole treatment for more than three years had higher odds of having mood disturbance (adjusted odds ratio 20.31, confidence interval 1.75 to 235.31, p = 0.016). No significant association was established between serum oestrogen levels and development of mood disturbance and dizziness. Conclusion: Our study confirmed that although mood disturbances and dizziness are not the most commonly reported adverse reactions, the duration of Anastrozole treatment may be a predictor of mood disturbance in these patients.