A review of the BIG results: the Breast International Group 1-98 trial analyses.

Patients treated surgically for early breast cancer show a peak recurrence 2 years following surgery. Distant metastases are the most common recurrence event and are associated with an increased risk of dying from breast cancer within 5 years. Consequently, reducing the risk of distant metastases is an important therapeutic goal. The use of an aromatase inhibitor (AI) as initial adjuvant therapy has been shown to reduce the risk of early recurrence. The Breast International Group 1-98 primary core analysis demonstrated that letrozole is the only AI in the initial adjuvant setting to demonstrate a significant 27% reduction in early distant metastases at 25.8 months in hormone receptor-positive patients. Once patients are diagnosed with distant metastases, they have incurable disease. Developing endocrine therapies to reduce the risk of distant metastases is, therefore, critically important therapeutic goal.