197. GnRH Agonists (Lupron/Zoladex) for Ovarian Function Suppression in Premenopausal Hormone Receptor Positive Breast Cancer: Monthly vs Every 3 Months?

Ovarian function suppression (OFS) is a key part of treatment for many premenopausal patients with hormone receptor–positive breast cancer, and is combined with tamoxifen or an aromatase inhibitor. OFS can be achieved surgically by removing the ovaries or medically with GnRH agonists such as Lupron or Zoladex. At the 2026 ASCO Annual Meeting, a meta-analysis of 15 studies by Pedro Reis et al (Abstract 542) involving more than 4,300 patients compared monthly versus every-3-month GnRH agonist dosing. The findings suggest that every-3-month dosing provides ovarian suppression, survival outcomes, and safety profiles comparable to monthly administration. However, the study also found that approximately 10% of patients experienced ovarian escape (inadequate ovarian suppression), with rates rising to 31% when ultrasensitive estradiol assays were used. What these findings mean in practice—and whether routine estradiol monitoring should become standard—remains unclear. In this episode, Dr. Eleonora Teplinsky breaks down the study, discuss how it may influence clinical practice, and explore the ongoing questions surrounding ovarian suppression, estradiol monitoring, and treatment optimization for premenopausal patients with hormone receptor–positive breast cancer. Links: Follow Dr. Teplinsky on Instagram @drteplinsky, on TikTok, YouTube, or on any other social media platform. You can also visit her website at http://www.drteplinsky.com. Books: “Beyond The Pink” by Dr. Eleonora Teplinsky (out 9/29/2026- pre order today!). Medical Disclaimer: The information provided in this episode is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.