Phase III study of letrozole versus tamoxifen as first-line therapy of advanced breast cancer in postmenopausal women: Analysis of survival and update of efficacy from the International Letrozole Breast Cancer Group

Henning Mouridsen, Mikhail Gershanovich, Yan Sun, Ramón Pérez-Carrión, Corrado Boni, Alain Monnier, Justus Apffelstaedt, Robert Smith, Harm P. Sleeboom, Fritz Jaenicke, Anna Pluzanska, Magdolna Dank, Dominique Becquart, Poonamalle P. Bapsy, Eeva Salminen, Ray Snyder, Hilary Chaudri-Ross, Raquel Lang, Peter Wyld, Ajay Bhatnagar

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To analyze overall survival (OS) and update efficacy data for letrozole versus tamoxifen as first-line therapy in postmenopausal women with locally advanced or metastatic breast cancer. Patients and Methods: This multicenter phase III trial randomly assigned 916 patients with hormone receptor-positive or unknown tumors letrozole 2.5 mg (n = 458) or tamoxifen 20 mg (n = 458) daily until disease progression. Optional cross-over was permitted at the treating physician's discretion. This report updates efficacy at a median follow-up of 32 months. Results: The superiority of letrozole to tamoxifen was confirmed for time to progression (median, 9.4 v 6.0 months, respectively; P <.0001), time to treatment failure (median, 9 v 5.7 months, respectively; P <.0001), overall objective response rate (32% v 21%, respectively; P = .0002), and overall clinical benefit. Median OS was slightly prolonged for the randomized letrozole arm (34 v 30 months, respectively). Although this difference in OS is not significant, survival was improved in the randomized letrozole arm over the first 2 years of the study. Approximately one half of the patients in each arm crossed over. Total duration of endocrine therapy ("time to chemotherapy") was significantly longer (P = .005) for patients initially on letrozole (median, 16 months) than for patients initially on tamoxifen (median, 9 months). Time to worsening of Karnofsky performance score was significantly delayed with letrozole compared with tamoxifen (P = .001). Conclusion: This study documents the superiority of letrozole over tamoxifen in first-line endocrine therapy in postmenopausal women with advanced breast cancer.

Original languageEnglish
Pages (from-to)2101-2109
Number of pages9
JournalJournal of Clinical Oncology
Volume21
Issue number11
DOIs
Publication statusPublished - Jun 1 2003

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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