Based on the most currently available evidence, the authors of a paper published in the Journal of Clinical Oncology developed a risk score to guide selection of adjuvant endocrine therapy for premenopausal women with hormone receptor (HR)-positive, HER2-negative, early-stage breast cancer.1
The majority of premenopausal women with early-stage breast cancer are found to have HR-positive disease, and are therefore candidates for endocrine therapy. Nevertheless, the presence of intact ovarian function, and the potential impact of endocrine therapy on fertility and quality of life, can complicate selection of endocrine therapy in this population of patients. In addition, younger women with the disease are more likely than their older counterparts to have a more aggressive tumor subtype.
Over the last several years, results from the Suppression of Ovarian Function Trial (SOFT; premenopausal women with HR-positive, early-stage breast cancer were randomly assigned to receive tamoxifen, tamoxifen plus ovarian suppression, or exemestane plus ovarian suppression for 5 years), and the Tamoxifen and Exemestane Trial (TEXT; this population of patients were randomized to treatment with tamoxifen plus ovarian suppression or exemestane plus ovarian suppression) have provided important insights to guide and improve endocrine therapy treatment selection in premenopausal women with early-stage breast cancer.2,3
This study involved a secondary analysis of the SOFT and TEXT studies in which data related to patient age, tumor size, nodal status, disease grade, and levels of tumor expression of estrogen receptor, progesterone receptor, and Ki-67 for 4891 patients with HR-positive/HER2-negative disease were combined into a “continuous composite measure of recurrence risk,” allowing for assignment of a risk score — called the Regan risk score — for individual patients based on these factors.
A key finding of this study was that while tamoxifen alone was deemed appropriate for women with a low-risk score, those at high risk of disease recurrence according to the Regan risk score appeared to have a 10% to 15% absolute improvement in 8-year freedom from distant recurrence if they received exemestane plus ovarian suppression as compared with tamoxifen plus ovarian suppression or tamoxifen alone.
The study authors noted that “an online tool is in development to assist clinicians with using SOFT/TEXT in their daily practice risk/benefit calculations in premenopausal women with HR-positive/HER2-negative breast cancer.”
- Pagani O, Francis PA, Fleming GF, et al. Absolute improvements in freedom from distant recurrence to tailor adjuvant endocrine therapies for premenopausal women: Results from TEXT and SOFT [published online October 16, 2019]. J Clin Oncol. doi: 10.1200/JCO.18.01967.
- Pagani O, Regan MM, Walley BA, et al; for the TEXT and SOFT Investigators and the International Breast Cancer Study Group. Adjuvant exemestane with ovarian suppression in premenopausal breast cancer. N Engl J Med. 2014;371(2):107-118.
- Francis PA, Regan MM, Fleming GF, et al; for the SOFT Investigators and the International Breast Cancer Study Group. Adjuvant ovarian suppression in premenopausal breast cancer. N Engl J Med. 2015;372(5):436-446.