在乳腺癌患者中，有关种族差异是否存在于新辅助化疗（NACT）后实现病理学完全缓解（pCR）的研究结果不一致。为了调查在实现pCR方面是否存在种族差异以及有哪些因素会导致种族差异，该单机构研究在芝加哥多种族流行病学乳腺癌队列（ChiMEC）的进行中确定了690名接受NACT的Ⅰ-Ⅲ期乳腺癌患者。包括2002年至2020年（中位随访时间：5.4年）之间被诊断的患者。186名ChiMEC患者的肿瘤-正常组织对的下一代测序数据得以获得，包括原发肿瘤和残留肿瘤样本。统计分析于2021年9月至2022年9月之间进行。分析了可能导致pCR差距的人口统计学、生物学和治疗因素。pCR定义为乳腺和腋窝结点中无侵袭性癌症，无论乳管内癌症如何。研究包括690名乳腺癌患者，平均年龄（SD）为50.1（12.8）岁。在355名白人患者中，有130人（36.6％）实现了pCR，而在269名黑人患者中，有77人（28.6％）实现pCR（P = 0.04）。未达到pCR与显着更差的总生存（校正危险比6.10；95％CI，2.80-13.32）有关。黑人患者与ERBB2+亚型的白人患者相比，实现pCR的可能性明显较低（校正比值比0.30；95％CI，0.11-0.81）。与ERBB2+疾病的白人患者相比，黑人患者更有可能具有MAPK通路变异（30.0％[20中的6]与4.6％[22中的1]；P=0.04），这是一种可能导致抗ERBB2治疗耐药的机制。原发性肿瘤和残留肿瘤中的肿瘤突变负荷和几种基因的体细胞突变（例如，FGF4，FGF3，CCND1，MCL1，FAT1，ERCC3，PTEN）之间存在显着差异。本队列研究的结果表明，在不同类型的乳腺癌亚型中，NACT的反应存在种族差异，这种差异与生存率的差异相关。该研究强调了更好地理解原发性和残留肿瘤的生物学可能带来的潜在好处。

Among patients with breast cancer, inconsistent findings have been published on racial disparities in achieving pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT).To investigate whether racial disparities exist in achieving pCR and what factors contribute to them.Within the ongoing Chicago Multiethnic Epidemiologic Breast Cancer Cohort (ChiMEC), which consists of a prospectively ascertained cohort of patients with breast cancer, 690 patients with stage I to III breast cancer receiving NACT were identified for this single-institution study at the University of Chicago Medicine. Patients diagnosed between 2002 and 2020 (median follow-up: 5.4 years) were included; next-generation sequencing data on tumor-normal tissue pairs were available from 186 ChiMEC patients, including both primary and residual tumor samples. Statistical analysis was performed from September 2021 to September 2022.Demographic, biological, and treatment factors that could contribute to disparities in achieving pCR.pCR was defined as the absence of invasive cancer in the breast and axillary nodes, irrespective of ductal carcinoma in situ.The study included 690 patients with breast cancer, with a mean (SD) age of 50.1 (12.8) years. Among the 355 White patients, 130 (36.6%) achieved pCR compared to 77 of the 269 Black patients (28.6%; P = .04). Not achieving pCR was associated with significantly worse overall survival (adjusted hazard ratio, 6.10; 95% CI, 2.80-13.32). Black patients had significantly lower odds of achieving pCR compared with White patients in the hormone receptor-negative/ERBB2+ subtype (adjusted odds ratio, 0.30; 95% CI, 0.11-0.81). Compared with White patients with ERBB2+ disease, Black patients were more likely to have MAPK pathway alterations (30.0% [6 of 20] vs 4.6% [1 of 22]; P = .04), a potential mechanism of anti-ERBB2 therapy resistance. Tumor mutational burden and somatic alterations in several genes (eg, FGF4, FGF3, CCND1, MCL1, FAT1, ERCC3, PTEN) were significantly different between the primary and residual tumors.In this cohort study of patients with breast cancer, racial disparities in response to NACT were associated with disparities in survival and varied across different breast cancer subtypes. This study highlights the potential benefits of better understanding the biology of primary and residual tumors.