Aims Clinical guidelines for breast cancer management have evolved in the past decade. However, limited evidence exists regarding uptake of novel drug classes in management of hormone receptor‐positive (HR+) metastatic breast cancer (MBC) in the USA and whether disparities exist by race and ethnicity. Methods Using SEER‐Medicare databases, we identified 4404 women aged ≥66 years diagnosed with HR+ de novo MBC (dnMBC) between 2010 and 2019. Age‐standardized rates for receipt of first‐line treatment were calculated. Age‐adjusted rate ratios (RRs) and 95% confidence intervals (CIs) were estimated using Poisson regression to compare rates among non‐Hispanic Black (NHB) and Hispanic patients with non‐Hispanic White (NHW) patients. Results Among patients with HR+/human epidermal growth factor receptor 2‐negative (HER2−) dnMBC after 2015, 48.6% received first‐line treatment with aromatase inhibitors (AIs) and 22.8% with AIs plus cyclin‐dependent kinase (CDK) 4/6 inhibitors. Rates for AIs + CDK4/6 inhibitors increased (per 1000 person‐years: 262.2 in 2015; 452.8 in 2019). Compared with NHW, NHB (RR 95% CI%: 0.87 0.63–1.21) and Hispanic patients (RR 95% CI%: 0.74 0.51–1.08) were less likely to receive AIs + CDK4/6 inhibitors. For HR+/HER2+ dnMBC, 29.7% of patients received pertuzumab, 23.1% with AIs and 10.8% with AIs + trastuzumab. Rates for pertuzumab increased, while rates for trastuzumab monotherapy declined. Compared with NHW, NHB and Hispanic women were less likely to receive anti‐HER therapy (RR 95% CI: 0.51 0.35–0.73 and 0.58 0.39–0.86). Conclusion There is a temporal increase in first‐line treatment with AIs + CDK4/6 inhibitors and pertuzumab in dnMBC in the USA but with significant disparities by race and ethnicity.
Zhu et al. (Wed,) studied this question.