Suppressing ovarian estrogen production along with tamoxifen may benefit premenopausal women at high risk of breast cancer recurrence who required adjuvant chemotherapy, however, it did not provide a significant benefit to the overall study population, according to a trial of 3,066 women with hormone-receptor-positive early breast cancer.

Researchers randomized premenopausal breast cancer survivors to receive either 5 years of tamoxifen, tamoxifen plus ovarian suppression, or exemestane plus ovarian suppression therapy. Subjects were also stratified according to whether or not they had received chemotherapy.

After an average of 67 months of follow up, the 5-year disease-free rates were as follows:

• tamoxifen-ovarian suppression: 86.6%

• exemestane-ovarian suppression: 85.7%

• tamoxifen only: 84.7%

Among patients who were at sufficient risk for recurrence to warrant adjuvant chemotherapy, the 5-year cancer-free rates were:

• tamoxifen–ovarian suppression: 82.5%

• tamoxifen only: 78.0%

Citation: Francis PA, Regan MM, Fleming GF, et al; SOFT Investigators; International Breast Cancer Study Group. Adjuvant ovarian suppression in premenopausal breast cancer. N Engl J Med. 2015;372(5):436-446. doi: 10.1056/NEJMoa1412379