In a German trial (WSG-ADAPT-HR1/HER2–) reported in the Journal of Clinical Oncology, Nitz et al found no difference in invasive disease-free survival between women with early hormone receptor–positive, HER2-negative breast cancer with zero to three positive nodes who had a 21-gene recurrence score (RS) ≤ 11 vs those with RS of 12 to 25 who responded to 3 weeks of preoperative endocrine therapy.
In the trial, which enrolled patients between May 2012 and September 2019, 2,290 patients with zero to three positive nodes received endocrine therapy alone. Those with RS ≤ 11 constituted the control group (n = 868). Those with RS 12 to 25 who responded to 3 weeks of preoperative endocrine therapy, with response defined as Ki67 ≤ 10%, constituted the experimental group (n = 1,422). All other patients (n = 2,331, including 694 with zero to three positive nodes and RS 12 to 25 without endocrine therapy response) received dose-dense chemotherapy followed by endocrine therapy. The primary endpoint was 5-year invasive disease–free survival in the endocrine therapy experimental vs control groups.
Key Findings
At 5 years, invasive disease–free survival was 92.6% (95% confidence interval [CI] = 90.8%–94.0%) in the experimental group vs 93.9% (95% CI = 91.8%–95.4%) in the control group; the one-sided 95% lower confidence limit of the difference was –3.3%, meeting the prespecified criterion for noninferiority (P = .05). Among the endocrine therapy nonresponders with zero to three positive nodes and RS 12 to 25 who received chemotherapy, 5-year invasive disease–free survival was 90.3% (95% CI = 87.2%–92.6%).
At 5 years, distant disease–free survival was 95.6% (95% CI = 94.2%–96.7%) in the experimental group vs 96.3% (95% CI = 94.6%–97.5%) in the control group (P = .247). The rate was 92.8% (95% CI = 90.1%–94.8%) among the endocrine therapy nonresponders receiving chemotherapy.
At 5 years, overall survival was 97.3% (95% CI = 96.1%–98.1%) in the experimental group vs 98.0% (95% CI = 96.6%–98.9%) in the control group (P = .160). The rate was 96.7% (95% CI = 94.6%–98.0%) among the endocrine therapy nonresponders who received chemotherapy.
The investigators concluded: “WSG-ADAPT-HR1/HER2– demonstrates that guiding systemic treatment by both RS and [endocrine therapy] response is feasible in clinical routine and spares [chemotherapy] in pre- and postmenopausal patients with ≤ 3 involved lymph nodes.”
Nadia Harbeck, MD, PhD, Breast Center, Department of Obstetrics and Gynecology and CCC Munich, LMU University Hospital, Munich, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: For full disclosures of the study authors, visit www.ascopubs.org.
