William J. Gradishar, MD, Director, Maggie Daley Center for Women's Cancer Care, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, discusses results from the international ATLAS study that was presented at the 2012 San Antonio Breast Cancer Symposium.

ATLAS enrolled 6846 women with estrogen receptor-positive breast cancer who had received 5 years of prior adjuvant tamoxifen. In the trial, patients were randomized to receive no tamoxifen or an additional 5 years of treatment. Overall, those who received 10 years of tamoxifen experienced a 25% lower recurrence rate and 29% lower mortality rates. The risk of dying due to breast cancer was also lower for those receiving an additional 5 years of treatment.

Gradishar notes that a benefit for the additional treatment was not evident in years 5 to 9. The greatest benefit was observed after 10 years of treatment. Due to the current standard of care, this information may have the greatest impact for premenopausal women who are not candidates for aromatase inhibitors, Gradishar points out.