ASTRRAnomical news.

Top Line: Let's be honest, ovarian suppression in addition to endocrine therapy for premenopausal women with hormone-receptor(+) breast cancer is confusing.

The Study: That confusion comes from the initially negative—then positive—SOFT/TEXT results, the confusing third-arm caveat of exemestane, and the fact that it was probably “high risk” patients receiving chemo who benefited most. The more recent (and cleaner?) ASTRRA trial from the Korean Breast Cancer Study Group randomized almost 1500 premenopausal women with hormone-receptor(+) breast cancer to 5 years of tamoxifen +/- ovarian suppression. To be eligible, these women had to be 45 years or younger and have received surgery and chemo. Remember, only roughly half of SOFT patients received chemo. Importantly, they remained eligible for randomization up to 2 years after chemo, as soon as ovarian function resumed (FSH < 30 mIU/mL or menses). They were then randomized to receive +/- 2 years of the GnRH agonist goserelin (aka Zoladex). Just over 10% of patients maintained ovarian function through chemo and another 54% resumed ovarian function within 6 months. Another 28% resumed ovarian function between 6 months and 2 years, and (surprisingly?) only 6% stayed in menopause. Indeed, the addition of ovarian suppression resulted in a small but significant improvement in disease-free (87→ 91%) and even overall (98→ 99%) survival at 5 years.

TBL: In young women who regain ovarian function after chemo for hormone receptor(+) breast cancer, ovarian suppression in addition to endocrine therapy was shown to improve overall survival for the first time. | Kim, J Clin Oncol 2019