Phase III Comparison of Tamoxifen Versus Tamoxifen Plus Ovarian Function Suppression in Premenopausal Women With Node-Negative, Hormone Receptor-Positive Breast Cancer (E-3193, INT-0142): A Trial of the Eastern Cooperative Oncology Group

Purpose The effects of ovarian function suppression (OFS) on survival and patient-reported outcomes were evaluated in a phase III trial in which premenopausal women were randomly assigned to tamoxifen with or without OFS. Patients and Methods Premenopausal women with axillary node-negative, hormone receptor-positive breast cancer tumors measuring <= 3 cm were randomly assigned to tamoxifen alone versus tamoxifen plus OFS; adjuvant chemotherapy was not permitted. Primary end points were disease-free survival (DFS) and overall survival (OS). Secondary end points included toxicity and patient-reported outcomes. Patient-reported outcome data included health-related quality of life, menopausal symptoms, and sexual function. These were evaluated at baseline, 6 months, 12 months, and then annually for up to 5 years after registration. Results In all, 345 premenopausal women were enrolled: 171 on tamoxifen alone and 174 on tamoxifen plus OFS. With a median follow-up of 9.9 years, there was no significant difference between arms for DFS (5-year rate: 87.9% v 89.7%; log-rank P = .62) or OS (5-year rate: 95.2% v 97.6%; log-rank P = .67). Grade 3 or higher toxicity was more common in the tamoxifen plus OFS arm (22.4% v 12.3%; P = .004). Patients treated with tamoxifen plus OFS had more menopausal symptoms, lower sexual activity, and inferior health-related quality of life at 3-year follow-up (P < .01 for all). Differences diminished with further follow-up. Conclusion When added to tamoxifen, OFS results in more menopausal symptoms and sexual dysfunction, which contributes to inferior self-reported health-related quality of life. Because of early closure, this study is underpowered for drawing conclusions about the impact on survival when adding OFS to tamoxifen. (C) 2014 by American Society of Clinical Oncology