ESMO Breast 2021: Does Clinical Benefit From Endocrine Therapy Differ by Risk Group?
Posted: Thursday, May 27, 2021
Annelie Johansson, PhD, of the Karolinska Institute, Stockholm, and colleagues presented the 20-year follow-up of premenopausal women with estrogen receptor–positive breast cancer and stratification by the 70-gene risk signature at the European Society for Medical Oncology (ESMO) Breast Cancer Virtual Congress 2021 (Abstract LBA1). The results of this study suggested that low-risk patients achieve a greater benefit with tamoxifen, whereas patients at high risk of disease recurrence achieve a significant benefit with goserelin.
The study discussant, Prudence Francis, MD, of Peter MacCallum Cancer Centre, Melbourne, called this “an innovative translational study assessing the differential benefits of endocrine therapies according to multigene assay results,” in an ESMO press release.
The investigators focused on 924 premenopausal patients with breast cancer who were randomly assigned across four arms: 2 years of goserelin, tamoxifen, the combination of goserelin and tamoxifen, and no endocrine therapy. Women who had lymph node–positive disease (n = 459) were administered standard chemotherapy.
In 729 patients, clinically relevant markers of breast cancer were identified by immunohistochemistry, and in 589 samples, microarray profiling was performed. The 70-gene signature was used to classify patients as being at high or low risk of recurrence, and long-term (20 years) follow-up was obtained from Swedish high-quality national registries.
This analysis showed that all 610 patients with estrogen receptor–positive disease had a reduced 20-year risk of distant recurrence with goserelin (hazard ratio [HR] = 0.48), tamoxifen (HR = 0.59), and the goserelin-plus-tamoxifen combination (HR = 0.67), compared with participants who did not receive endocrine therapy (HR = 1.00).
Based on stratification by the 70-gene signature, 306 patients who were at low risk demonstrated a significant benefit from tamoxifen (HR = 0.38), whereas goserelin (HR = 0.80) and the combination therapy (HR = 0.72) did not provide such a benefit in these patients. However, 159 patients in the high-risk category obtained a significant benefit from goserelin (HR = 0.22) when compared with tamoxifen (HR = 0.69) and the combination (HR = 0.64).
Disclosure: For full disclosures of the study authors, visit oncologypro.esmo.org.