Data Support Ovarian Function Suppression for 2 Years in Certain Breast Cancer Patients

Updated data support the use of ovarian function suppression for 2 years in patients with estrogen receptor (ER)-positive breast cancer who remain premenopausal or resume ovarian function after chemotherapy, according to researchers.¹

The researchers found that 2 years of ovarian function suppression plus tamoxifen improved disease-free survival (DFS) over tamoxifen alone in this patient population.

These results, from the phase 3 ASTRRA trial (ClinicalTrials.gov Identifier: NCT00912548), were published in the Journal of Clinical Oncology.

The original results from the ASTRRA trial showed that 5 years of tamoxifen plus 2 years of goserelin resulted in significantly improved DFS and overall survival (OS), when compared with 5 years of tamoxifen alone, in patients who had ER-positive breast cancer and were 45 years of age or younger.²

In this follow-up analysis, long-term data were available for 1231 patients — 610 who received goserelin plus tamoxifen and 621 who received tamoxifen alone.¹

At a median follow-up of 106.4 months, DFS remained significantly better among patients assigned to the goserelin arm (hazard ratio [HR], 0.67; 95% CI, 0.51-0.87; P =.003). The 8-year DFS rate was 85.4% in the goserelin-tamoxifen arm and 80.2% in the tamoxifen-alone arm.

The recurrence-free interval, breast cancer-free interval, and distant metastasis-free survival were superior in the goserelin arm as well. At 8 years, the recurrence-free interval rate was 87.5% in the goserelin arm and 83.4% in the tamoxifen-alone arm (HR, 0.70; 95% CI, 0.52-0.93).

The 8-year breast cancer-free interval rate was 86.3% in the goserelin arm and 82.4% in the tamoxifen-alone arm (HR, 0.71; 95% CI, 0.54-0.94). The 8-year distant metastasis-free survival rate was 89.4% and 85.1%, respectively (HR, 0.71; 95% CI, 0.52-0.96).

The 8-year OS rate was similar between the arms. It was 96.5% in the combination arm and 95.3% in the monotherapy arm (HR, 0.78; 95% CI, 0.49-1.25; P =.305).

“The current guideline recommends 5 years of OFS [ovarian function suppression],” the researchers noted. “Considering the significant OS rates of more than 95% at 8 years in both groups and the potential risk and negative effect on quality of life associated with OFS, using OFS for 2 years could be acceptable for selected patients.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

References

1. Baek SY, Noh WC, Ahn S-H, et al. Adding ovarian suppression to tamoxifen for premenopausal women with hormone receptor–positive breast cancer after chemotherapy: An 8-year follow-up of the ASTRRA Trial. J Clin Oncol. Published online August 22, 2023. doi:10.1200/JCO.23.00557

2. Kim HA, Lee JW, Nam SJ, et al. Adding ovarian suppression to tamoxifen for premenopausal breast cancer: A randomized phase III trial. J Clin Oncol. 2020;38(5):434-443. doi:10.1200/JCO.19.00126

This article originally appeared on Cancer Therapy Advisor