Background: Exemestane (E) is a steroidal aromatase inactivator, which has been demonstrated to be more effective than tamoxifen (T) in metastatic breast cancer (BC). The role of E in adjuvant therapy has been established after 2 to 3 years of T compared to 5 years of T in the Intergroup Exemestane Study (Lancet 2007; 369: 599-70). One objective of the TEAM study was to evaluate E compared to T as initial adjuvant endocrine therapy. Methods: Using common criteria, eligible postmenopausal patients in 9 countries with invasive ER+ and/or PR+ early BC, were prospectively randomized to either open-label E 25 mg/day or T 20 mg/day. All patients had completed primary therapy of surgery and chemotherapy if indicated. All data were collected and analyzed by the Central Data Center in Leiden, The Netherlands. The trial was initiated in 2001 with a primary endpoint of DFS between T and E. In 2004, based on results of the IES, TEAM was modified such that all patients on T were switched to E at 2.5-3 years. The modified design includes 2 primary endpoints: DFS of T versus E followed up to 2.75 years, and DFS of E for 5 years versus T switched to E treated for a total of 5 years. The present analysis focuses on the first primary endpoint: DFS for T compared to E at 2.75 years with censoring of events after 2.75 years. Log rank test with a 2-sided significance level of 2.98% stratified by country and factors nested in protocols will be utilized. Results: Between January 2001 and January 2006, 9775 women were randomized to T or E of which 9300 will be followed for 2.75 years by October 2008: 99% were ER and/or /PgR+, 50% were node negative, 44% underwent mastectomy, 68% received radiotherapy, and 36% chemotherapy. There have been 693 DFS events (locoregional or distant recurrence, second breast cancers, or death without recurrence) by April 2008 within 2.75 years of randomization. In accordance with the statistical analysis plan, the first planned analysis will be based on 723 events or 9300 patients with at least 2.75 years follow-up. We will present a detailed analysis of the first primary endpoint of DFS between T and E at 2.75 years at the 2008 SABCS. The TEAM study represents the largest of the 3 major trials to compare efficacy of an aromatase inhibitor/inactivator versus tamoxifen as initial endocrine therapy.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 15.
Thirty-first San Antonio Breast Cancer Symposium Dec 10-14, 2008; San Antonio, TX