Exemestane for Premenopausal Breast Cancer

Summary and Comment |
June 10, 2014

Exemestane for Premenopausal Breast Cancer

  1. William J. Gradishar, MD

Outcomes were significantly improved with adjuvant exemestane versus tamoxifen in hormone-receptor–positive patients treated with ovarian function suppression.

  1. William J. Gradishar, MD

Premenopausal women with early-stage, hormone-receptor–positive breast cancer will receive a recommendation of tamoxifen for at least 5 years and as long as 10 years. But whether adding ovarian function suppression (OFS) to tamoxifen or using an aromatase inhibitor (AI) with OFS offers an advantage in terms of recurrence or survival in this patient population has not been defined.

Investigators have now conducted two randomized, phase III trials (TEXT and SOFT) to compare tamoxifen plus OFS versus an AI (exemestane) plus OFS in 4690 premenopausal women with hormone-receptor–positive early breast cancer (median age, 43; 42% with node-positive disease; 57% received adjuvant chemotherapy).

After a median follow-up of 68 months, 5-year disease-free survival was significantly better with exemestane than with tamoxifen (91.1% vs. 87.3%; hazard ratio, 0.72 for disease recurrence, second invasive cancer, or death; P<0.001), as was the rate of freedom from breast cancer at 5 years (92.8% vs. 88.8%; HR, 0.66 for recurrence; P<0.001). Overall survival was similar between the groups.


These results suggest that exemestane plus OFS may be another option for young patients with hormone-sensitive breast cancer. Of note, the magnitude of benefit derived in this trial from an AI (plus OFS) is similar to the benefit seen in large adjuvant trials of postmenopausal patients comparing tamoxifen with an AI. Not answered by this analysis is whether these results are superior to 10 years of tamoxifen therapy or to 5 years of tamoxifen followed by an AI in patients who become postmenopausal. The potential benefit of adding OFS to endocrine therapy versus tamoxifen alone will be answered by the SOFT trial, perhaps as early as later this year. The adverse-effect profile of an AI in this young population is similar to that observed in older, postmenopausal patients, but whether acceptance will be equivalent in younger patients will require a careful analysis of compliance. Also of note, many patients in these trials did not receive chemotherapy and yet had an excellent prognosis with endocrine therapy alone. This finding emphasizes that not all premenopausal women require chemotherapy.

Editor Disclosures at Time of Publication

  • Disclosures for William J. Gradishar, MD at time of publication Consultant / Advisory board Biologics, Inc. Editorial boards Clinical Breast Cancer; Journal of Clinical Oncology; Oncology Leadership positions in professional societies American Society of Clinical Oncology (Nominating Committee Chair)


Reader Comments (1)


This is good, addition of exemestane have benefit in premenopausal women.

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