Chemotherapy declination among patients with early-stage HR-positive, HER2-negative breast cancer and high Oncotype DX scores

Although the 21-gene Oncotype DX assay predicts chemotherapy (CT) benefit in HR-positive, HER2-negative breast cancer (HR+ HER2- BC), some patients decline CT despite their physician’s recommendation. Analysis using the National Cancer Database (2018-2022) investigated factors associated with CT declination and its impact on overall survival (OS) among patients with clinical stage I-II HR+ HER2- BC who underwent definitive surgery and had recurrence score (RS) > 25. Among 30,326 patients, 10.9% declined CT, whereas 15.5% of these patients also declined hormonal therapy. Higher RS was associated with lower odds of CT declination. A more recent year of diagnosis and Hispanic race were also associated with lower odds of CT declination, while older age and Black race were associated with higher odds. Patients on Medicaid (aOR 1.53; 95% CI 1.15-1.45) and Medicare (1.19; 1.05-1.34) had higher odds of CT declination compared with those on private insurance. Having pN1 disease was associated with lower odds of CT declination than having pN0 disease. CT declination was associated with an increased risk of death (aHR 1.43; 95% CI 1.20-1.69). The authors conclude that despite a decrease in CT declination over time, disparities persist, and declination is associated with worse OS among patients with HR+ HER2- BC and a high RS.