Pre-menopausal breast cancer and aromatase inhibitors: treating a new generation of women

Aromatase inhibitors have revolutionized the treatment of post-menopausal women with hormone receptor positive breast cancer. However, approximately 22% of all cases of breast cancer in North America are diagnosed in women below the age of 50 and a substantial proportion of these women are pre-menopausal. In the pre-menopausal population with hormone receptor positive disease, research on the use of aromatase inhibitors is only beginning to emerge. In this review, the mechanism of action of aromatase inhibitors and the history of endocrine treatment for pre-menopausal breast cancer is briefly presented. Available research to date regarding efficacy and toxicity of aromatase inhibitors in the treatment of pre-menopausal breast cancer and future research directions are also discussed.