Aromatase inhibitors and bone health

Aromatase inhibitors improve survival in breast cancer patients but adversely affect bone health.

Hormone receptor positive breast cancer is increasingly targeted with chemotherapy, ovarian suppression and the use of aromatase inhibitors. Aromatase inhibitors block oestrogen production in peripheral tissues and the three third generation aromatase inhibitors (anastrozole, letrozole and exemestane) reduce circulating oestrogen levels, leading to accelerated bone loss and an increased risk of fracture.The majority of fractures occur in osteopaenic women prescribed aromatase inhibitors. Current guidelines advocate bone mineral density (BMD) measurement in all patients on aromatase inhibitors with selective use of antiresorptive therapy in osteoporotic (T-score > -2.5) women. Risk factors for premature bone loss and fracture include a low BMI, family history or personal history of fragility fracture after the age of 50, oral corticosteroid use more than 6 months and cigarette smoking. Emerging evidence supports concomitant use of bisphosphonates in all women on aromatase inhibitors to prevent fracture and breast cancer recurrence.

The increasing use of aromatase inhibitors requires selection of patients for antiresorptive therapy and careful bone health management to reduce bone loss and prevent fragility fractures.