PURPOSE Cutoffs of the 21-gene recurrence score (RS), a commonly used genomic assay for hormone receptor-positive breast cancer, have been updated. Little is known about racial/ethnic differences in RS results, RS-guided chemotherapy use, and outcomes on updated cutoff (RS ≥ 31 defined as high-risk) in the real-world setting. METHODS A total of 81,937 women [75.0% whites, 7.7% blacks, 8.3% Asian American/Pacific Islanders (AAPIs), and 9.0% Hispanics] diagnosed with hormone receptor-positive breast cancer between 2004 and 2015, who received the 21-gene assay, were identified from the Surveillance, Epidemiology, and End Results. Logistic regressions estimated the race-associated odds ratios (ORs) of RS and chemotherapy use. Cox regressions estimated the race-associated hazard ratios (HRs) of breast cancer-specific and all-cause mortality. RESULTS Compared with white women, black women were more likely to have RS-defined high-risk tumors (adjusted OR [aOR] 1.29; 95% CI 1.16-1.42). In high RS, blacks had lower odds of chemotherapy use (aOR 0.76; 95% CI 0.62-0.94) than whites, particularly among women ≥ 65 years (aOR 0.51; 95% CI 0.35-0.76), while AAPI and Hispanic women had no variation in chemotherapy use compared with whites in high RS. Black women had a higher risk of breast cancer-specific mortality (HR 1.37; 95% CI 1.12-1.67) and all-cause mortality compared with white women after adjusting for demographic and pathological factors, county-level socioeconomic deprivation, treatments and RS; AAPIs had lower mortality and Hispanics had similar mortality. CONCLUSIONS Black women were more likely to have a high-risk RS tumor and less likely to receive chemotherapy in the group of high RS, especially those ≥ 65 years. Further studies are needed to identify barriers to chemotherapy in black patients with high RS scores.

中文翻译：

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激素受体阳性、淋巴结阴性乳腺癌女性在 21 基因复发评分、化疗和生存率方面的种族和民族差异。

目的 21 基因复发评分 (RS) 是一种常用的激素受体阳性乳腺癌基因组检测方法，现已更新。对现实世界中 RS 结果、RS 指导的化疗使用和更新临界值（RS ≥ 31 定义为高风险）的结果的种族/民族差异知之甚少。方法 2004 年至 2015 年间，共有 81,937 名女性（白人占 75.0%，黑人占 7.7%，亚裔美国人/太平洋岛民 (AAPI) 占 8.3%，西班牙裔占 9.0%）被诊断患有激素受体阳性乳腺癌，她们接受了 21 基因检测、流行病学和最终结果。逻辑回归估计了 RS 和化疗使用的种族相关优势比 (OR)。Cox 回归估计了乳腺癌特异性死亡率和全因死亡率的种族相关风险比 (HR)。结果 与白人女性相比，黑人女性更可能患有 RS 定义的高风险肿瘤（调整后的 OR [aOR] 1.29；95% CI 1.16-1.42）。在高 RS 中，黑人使用化疗的几率（aOR 0.76；95% CI 0.62-0.94）低于白人，尤其是在 65 岁以上的女性中（aOR 0.51；95% CI 0.35-0.76），而 AAPI 和西班牙裔女性则没有与高 RS 的白人相比，化疗使用的差异。在调整人口和病理因素、县级社会经济贫困、治疗和 RS 后，与白人女性相比，黑人女性患乳腺癌特异性死亡率（HR 1.37；95% CI 1.12-1.67）和全因死亡率的风险更高；AAPI 的死亡率较低，西班牙裔的死亡率相似。结论 在高 RS 组中，尤其是 65 岁以上的黑人女性更可能患有高风险的 RS 肿瘤并且不太可能接受化疗。需要进一步的研究来确定 RS 评分高的黑人患者接受化疗的障碍。