Toxicity of Aromatase Inhibitors

Adjuvant hormonal therapy in hormone receptor–positive breast cancer is used for the prevention of disease recurrence and prolongation of survival. Aromatase inhibitors are increasingly being used for this purpose. Numerous studies now reveal their benefits over tamoxifen while demonstrating a markedly different toxicity profile. With greater use, a better understanding of the long-term effects of aromatase inhibitors on the prevention of cancer recurrence and on their long-term effects on chronic comorbid conditions will develop. Recognizing and understanding these toxicities, as well as the differences among the various aromatase inhibitors, will be crucial for all clinicians. When choosing the type of adjuvant hormonal therapy for each individual patient, comorbidities and quality-of-life parameters must be considered. In addition, ongoing studies evaluating these agents directly should reveal differences among them that may aid in determining the principal agent for use in this setting. In this article, we review the known toxicity profile of aromatase inhibitors and the current guidelines that exist in the diagnoses and management of these toxicities.