Clinical and economic benefits of aromatase inhibitor therapy in early-stage breast cancer.

PURPOSE: The clinical and economic benefits of aromatase inhibitor (AI) therapy in early-stage breast cancer are reviewed.
SUMMARY: AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer, as it significantly reduces the risk of disease recurrence and death. Using the currently accepted gold standard for clinical efficacy-improvement in disease-free survival rather than overall survival-exemestane, anastrozole, or letrozole as monotherapy or in sequence with tamoxifen has been found to be superior to tamoxifen monotherapy. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. Of the nonsteroidal AIs, letrozole appears to have the efficacy advantage by demonstrating an early effect on distant recurrence and, subsequently, a potentially significant overall survival benefit, though results of a prospective head-to-head trial of anastrozole and letrozole are not yet available. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence. However, preliminary analyses indicate that the survival benefit appears to be greater with letrozole than with anastrozole. Thus, considering potential survival benefits and cost-effectiveness, letrozole may be preferable to anastrozole in the early adjuvant setting.
CONCLUSION: AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence.