Adjuvant Exemestane with Ovarian Suppression in Premenopausal Breast Cancer

TLDR

The study compared adjuvant exemestane plus ovarian suppression with tamoxifen plus ovarian suppression in premenopausal women with hormone‑receptor‑positive early breast cancer. Ovarian estrogen production was suppressed using triptorelin, oophorectomy, or ovarian irradiation while patients received either exemestane or tamoxifen for five years. After a median 68‑month follow‑up, exemestane plus ovarian suppression improved 5‑year disease‑free survival (91.1% vs 87.3%, HR 0.72) and breast‑cancer–free survival (92.8% vs 88.8%, HR 0.66) compared with tamoxifen, with similar overall survival and grade 3/4 adverse‑event rates. The trial was funded by Pfizer and others and registered under ClinicalTrials.gov identifiers NCT00066703 and NCT00066690.

Abstract

Adjuvant therapy with an aromatase inhibitor improves outcomes, as compared with tamoxifen, in postmenopausal women with hormone-receptor-positive early breast cancer.In two phase 3 trials, we randomly assigned premenopausal women with hormone-receptor-positive early breast cancer to the aromatase inhibitor exemestane plus ovarian suppression or tamoxifen plus ovarian suppression for a period of 5 years. Suppression of ovarian estrogen production was achieved with the use of the gonadotropin-releasing-hormone agonist triptorelin, oophorectomy, or ovarian irradiation. The primary analysis combined data from 4690 patients in the two trials.After a median follow-up of 68 months, disease-free survival at 5 years was 91.1% in the exemestane-ovarian suppression group and 87.3% in the tamoxifen-ovarian suppression group (hazard ratio for disease recurrence, second invasive cancer, or death, 0.72; 95% confidence interval [CI], 0.60 to 0.85; P<0.001). The rate of freedom from breast cancer at 5 years was 92.8% in the exemestane-ovarian suppression group, as compared with 88.8% in the tamoxifen-ovarian suppression group (hazard ratio for recurrence, 0.66; 95% CI, 0.55 to 0.80; P<0.001). With 194 deaths (4.1% of the patients), overall survival did not differ significantly between the two groups (hazard ratio for death in the exemestane-ovarian suppression group, 1.14; 95% CI, 0.86 to 1.51; P=0.37). Selected adverse events of grade 3 or 4 were reported for 30.6% of the patients in the exemestane-ovarian suppression group and 29.4% of those in the tamoxifen-ovarian suppression group, with profiles similar to those for postmenopausal women.In premenopausal women with hormone-receptor-positive early breast cancer, adjuvant treatment with exemestane plus ovarian suppression, as compared with tamoxifen plus ovarian suppression, significantly reduced recurrence. (Funded by Pfizer and others; TEXT and SOFT ClinicalTrials.gov numbers, NCT00066703 and NCT00066690, respectively.).