Superior Efficacy of Letrozole Versus Tamoxifen as First-Line Therapy for Postmenopausal Women With Advanced Breast Cancer: Results of a Phase III Study of the International Letrozole Breast Cancer Group

American Society of Clinical Oncology (ASCO) - Tập 19 Số 10 - Trang 2596-2606 - 2001
Henning T. Mouridsen1, M. Gershanovich1, Yue-Li Sun1, R. Pérez-Carrión1, C. Boni1, Alain Monnier1, Justus Apffelstaedt1, Robert E. Smith1, Harm Sleeboom1, F. Jänicke1, A Płużańska1, Magdolna Dank1, D. Becquart1, P. P. Bapsy1, Eeva Salminen1, Ray Snyder1, M Lassus1, J. Arnold Verbeek1, Beatrix Staffler1, Hilary A. Chaudri‐Ross2,1, Margaret Dugan1
1From the Rigshospitalet, Copenhagen, Denmark; Petrov Research Institute of Oncology, St Petersburg, Russia; Chinese Academy of Medical Sciences, Beijing, China; Hospital Universitario de la Princesa, Madrid, Spain; Arcipedale Santa Maria Nuova, Reggio Emilia, Italy; Centre Hospitalier Général André-Boulloche, Montbéliard, France; University of Stellenbosch, Cape Town, South Africa; South Carolina Oncology Associates, Columbia, SC; Ziekenhuis Leyenburg, Den Haag, the Netherlands; University of Hamburg,...
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Tóm tắt

PURPOSE: To compare the efficacy and tolerability of tamoxifen with that of letrozole, an oral aromatase inhibitor, with tamoxifen as first-line therapy in postmenopausal women with advanced breast cancer. PATIENTS AND METHODS: Nine hundred seven patients were randomly assigned letrozole 2.5 mg once daily (453 patients) or tamoxifen 20 mg once daily (454 patients). Patients had estrogen receptor– and/or progesterone receptor–positive tumors, or both receptors were unknown. Recurrence during adjuvant antiestrogen therapy or within the following 12 months or prior endocrine therapy for advanced disease precluded enrollment. One prior chemotherapy regimen for metastatic disease was allowed. The primary end point was time to progression (TTP). Secondary end points included overall objective response rate (ORR), its duration, rate and duration of clinical benefit, time to treatment failure (TTF), overall survival, and tolerability. RESULTS: TTP was significantly longer for letrozole than for tamoxifen (median, 41 v 26 weeks). Treatment with letrozole reduced the risk of progression by 30% (hazards ratio, 0.70; 95% confidence interval, 0.60 to 0.82, P = .0001). TTP was significantly longer for letrozole irrespective of dominant site of disease, receptor status, or prior adjuvant antiestrogen therapy. Similarly, TTF was significantly longer for letrozole (median, 40 v 25 weeks). ORR was higher for letrozole (30% v 20%; P = .0006), as was the rate of clinical benefit (49% v 38%; P = .001). Survival data are currently immature and not reported here. Both treatments were well tolerated. CONCLUSION: Letrozole was significantly superior to tamoxifen in TTP, TTF, ORR, and clinical benefit rate. Our results support its use as first-line endocrine therapy in postmenopausal women with advanced breast cancer.

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American Society of Clinical Oncology (ASCO)

Tập 19 Số 10

2596-2606

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