Reducing early recurrence with adjuvant aromatase inhibitors: what is the evidence?

In early breast cancer, excision of the primary tumor, with or without radiotherapy and adjuvant chemotherapy or tamoxifen, is highly effective and yields long-term disease control for many patients. Some patients relapse early (within 2 years of surgery); such relapses are predominantly distant metastases and are associated with an increased risk for breast cancer-related mortality. The aromatase inhibitors (anastrozole, letrozole, and exemestane) have been shown to be superior to tamoxifen in improving disease-free survival in postmenopausal women with hormone receptor-positive breast cancer. Anastrozole and letrozole are approved in the initial adjuvant setting, and their use appears to be a better option than initial tamoxifen for preventing disease recurrence in the first 2 years of therapy, the peak time for recurrence and metastases. This review compares the ability of aromatase to prevent early recurrences, particularly distant metastases.