Aromatase Inhibitor Therapy in Breast Cancer

Patient Selection and Monitoring

• For women who become amenorrheic after chemotherapy, serial assessment of luteinizing hormone, follicle-stimulating hormone, and estradiol is mandatory to confirm true postmenopausal status before initiating aromatase inhibitor therapy, as recommended by the National Comprehensive Cancer Network 1

Mechanism of Action and Resistance

• Aromatase inhibitors unmask the inhibitory effect of androgens acting via the androgen receptor, providing a dual mechanism of tumor growth suppression, although the exact mechanisms of resistance are not fully understood, and may involve upregulation of alternative steroidogenic enzymes or constitutive ER activation 1