Publication

Five years of letrozole compared with tamoxifen as initial adjuvant therapy for postmenopausal women with endocrine-responsive early breast cancer: update of study BIG 1-98

Journal Paper/Review - Feb 10, 2007

Units
PubMed
Doi
Contact

Citation
Coates A, Del Mastro L, Smith I, Chirgwin J, Nogaret J, Pienkowski T, Wardley A, Jakobsen E, Price K, Láng I, Colleoni M, Keshaviah A, Thürlimann B, Mouridsen H, Mauriac L, Forbes J, Paridaens R, Castiglione-Gertsch M, Gelber R, Goldhirsch A. Five years of letrozole compared with tamoxifen as initial adjuvant therapy for postmenopausal women with endocrine-responsive early breast cancer: update of study BIG 1-98. JCO 2007; 25:486-92.
Type
Journal Paper/Review (English)
Journal
JCO 2007; 25
Publication Date
Feb 10, 2007
Issn Electronic
1527-7755
Pages
486-92
Brief description/objective

PURPOSE: Previous analyses of the Breast International Group (BIG) 1-98 four-arm study compared initial therapy with letrozole or tamoxifen including patients randomly assigned to sequential treatment whose information was censored at the time of therapy change. Because this presentation may unduly reflect early events, the present analysis is limited to patients randomly assigned to the continuous therapy arms and includes protocol-defined updated results. PATIENTS AND METHODS: Four thousand nine hundred twenty-two of the 8,028 postmenopausal women with receptor-positive early breast cancer randomly assigned (double-blind) to the BIG 1-98 trial were assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen; the remainder of women were assigned to receive the agents in sequence. Disease-free survival (DFS) was the primary end point. RESULTS: At a median follow-up time of 51 months, we observed 352 DFS events among 2,463 women receiving letrozole and 418 events among 2,459 women receiving tamoxifen. This reflected an 18% reduction in the risk of an event (hazard ratio, 0.82; 95% CI, 0.71 to 0.95; P = .007). No predefined subsets showed differential benefit. Adverse events were similar to previous reports. Patients on tamoxifen experienced more thromboembolic events, endometrial pathology, hot flashes, night sweats, and vaginal bleeding. Patients on letrozole experienced more bone fractures, arthralgia, low-grade hypercholesterolemia, and cardiovascular events other than ischemia and cardiac failure. CONCLUSION: The present updated analysis, which was limited to patients on monotherapy arms in BIG 1-98, yields results similar to those from the previous primary analysis but more directly comparable with results from other trials of continuous therapy using a single endocrine agent.