In a joint analysis of two clinical trials reported at the American Society of Clinical Oncologists meeting in Chicago, researchers found that premenopausal women undergoing hormone suppression and who were treated with Aromasin® (exemestane) had reduced breast cancer recurrence relative to those treated with tamoxifen. There was not, however, a difference in overall survival after 68 months of follow up.
The growth of one type of breast cancer, HR positive (HR+) breast cancer, is, in part, fueled by the hormone estrogen. One aspect of treating HR+ breast cancer is to medically suppress the ovaries, which produce estrogen, and thereby slow the growth of the tumor.
The TEXT and SOFT clinical trials enrolled 4690 patients with early HR+ breast cancer who had undergone some form of ovary (estrogen) suppression. The patients were then randomized to treatment with Aromasin or tamoxifen.
After a 5-year course of treatment, the Aromasin group improved disease-free survival by 28% relative to the tamoxifen patients. Both groups had comparable overall survival after 68 months of follow-up.
The two arms of the study also had comparable rates of adverse events due to treatment, 30.6% for the Aromasin group and 29.4% for the tamoxifen patients. Similarly, quality of life assessments for the two treatments did not favor either group.
The researchers concluded that Aromasin plus ovary suppression provides a viable new treatment for premenopausal women with HR+ breast cancer.
Reference: Pagani O, et al. Adjuvant exemestane with ovarian suppression in premenopausal breast cancer. N Engl J Med 2014; DOI: 10.1056/NEMJoa1404037.