Dr. O'Shaughnessy on Clinical Implications of the TEXT and SOFT Trials in Breast Cancer

Joyce A. O’Shaughnessy, MD, co-chair of Breast Cancer Research, chair of Breast Cancer Prevention Research at Baylor-Sammons Cancer Center, Texas Oncology, chair of The US Oncology Network, and 2016 Giant of Cancer Care^® in Community Outreach, discusses the clinical implications of the TEXT and SOFT trials in premenopausal women with hormone receptor-positive breast cancer.

Based on 8-year follow-up from the TEXT and SOFT trials, the most important practical point with regard to endocrine therapy for premenopausal women is that those who have very low-risk indolent disease who are not going to receive chemotherapy may do fine with tamoxifen alone provided that they are not too young, says O'Shaughnessy; these are women under the age of 35 or even 40. Women over the age of 40 with very indolent, low-risk disease are also appropriate to receive tamoxifen monotherapy.

Conversely, the more high-risk features younger women have, the greater the benefit of an aromatase inhibitor (AI) plus an LHRH agonist, says O’Shaughnessy. These features include progesterone receptor (PR) negativity, large grade 3 cancers, highly proliferative disease, and node-positive disease. These data provide invaluable insight into the use of endocrine therapy, which is critically significant as it is by far the most important therapy for premenopausal estrogen receptor (ER)-positive women, says O’Shaughnessy. For these patients with high-risk features, there is up to a 15% absolute benefit in distant disease-free survival with the use of an LHRH agonist in combination with an AI.