Combined Tamoxifen and Luteinizing Hormone-Releasing Hormone (LHRH) Agonist Versus LHRH Agonist Alone in Premenopausal Advanced Breast Cancer: A Meta-Analysis of Four Randomized Trials

Abstract

PURPOSE: The logic behind the application of luteinizing hormone-releasing hormone (LHRH) agonists in combination with tamoxifen in premenopausal women is that LHRH agonists on the one hand suppress the tamoxifen-induced stimulation of the pituitary-ovarian function and, on the other hand, seem as effective as surgical castration. This meta-analysis combines all randomized evidence to compare the combined treatment with LHRH agonist alone with respect to overall survival, progression-free survival, and objective response in premenopausal women with advanced breast cancer. PATIENTS AND METHODS: Four clinical trials randomizing a total of 506 premenopausal women with advanced breast cancer to LHRH agonist alone or to the combined treatment of LHRH agonist plus tamoxifen were identified. Meta-analytic techniques were used to analyze individual patient data from these trials. RESULTS: With a median follow-up of 6.8 years, there was a significant survival benefit (stratified log-rank test, P = .02; hazards ratio [HR] = 0.78) and progression-free survival benefit (stratified log-rank test, P = .0003; HR = 0.70) in favor of the combined treatment. The overall response rate was significantly higher on combined endocrine treatment (stratified Mantel Haenszel test, P = .03; odds ratio = 0.67). CONCLUSION: The combination of LHRH agonist plus tamoxifen is superior to LHRH agonist alone in premenopausal women with advanced breast cancer. Therefore, if a premenopausal woman with advanced breast cancer is thought to be suitable for endocrine treatment, it is proposed that the combination of a LHRH agonist plus tamoxifen be considered as the new standard treatment.