Department of Population Health Sciences, Duke University School of Medicine, 215 Morris Street, Suite 210, Durham, NC, 27701, USA.
University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Breast Cancer Res Treat. 2024 Jan;203(2):329-338. doi: 10.1007/s10549-023-07142-4. Epub 2023 Oct 24.
Treatment for HER2-low [defined as ImmunoHistoChemistry (IHC) 1 + or 2 + and negative/normal in Situ Hybridization (ISH)] breast cancer patients is rapidly evolving, yet we lack critical information about the HER2-low population.
We conducted a retrospective cohort study of women aged 18 years or older diagnosed with breast cancer between 2010 and 2016 in North Carolina. Analyses were conducted for the overall cohort and a stage IV sub-cohort. We examined demographic and clinical characteristics, and characterized prevalence of HER2-low disease and healthcare utilization. We estimated adjusted rate ratios for the association between HER2 classifications and utilization outcomes, and hazard ratios for 3-year all cause mortality (stage IV only).
The overall and stage IV cohorts included 12,965 and 635 patients, respectively. HER2-low patients represented more than half of both cohorts (59% overall, 53% stage IV). HER2-low patients were more likely than IHC 0 patients to have hormone receptor (HR)-positive disease. In the stage IV cohort, HER2-low patients were more likely to be Black (26% vs. 16% IHC 0, p = 0.0159). In both cohorts, rates of hospitalizations were slightly higher among HER2-low patients. There were no survival differences between HER2-low and IHC 0 among stage IV patients.
New treatment options for HER2-low breast cancer may have potential for significant impact at the population level particularly for patients with stage IV disease. In light of racial differences between HER2-low and IHC 0 patients observed in our cohort, research- and practice-based efforts to ensure equitable adoption of new treatment guidelines for patients with HER2-low metastatic breast cancer will be essential.
HER2 低表达（定义为免疫组织化学（IHC）1+或 2+且原位杂交（ISH）阴性/正常）乳腺癌患者的治疗方法正在迅速发展，但我们对 HER2 低表达人群缺乏关键信息。
我们对 2010 年至 2016 年期间在北卡罗来纳州诊断为乳腺癌的 18 岁及以上女性进行了回顾性队列研究。对总队列和 IV 期亚队列进行了分析。我们检查了人口统计学和临床特征，并描述了 HER2 低表达疾病的流行情况和医疗保健利用情况。我们估计了 HER2 分类与利用结果之间的关联的调整率比，并估计了仅 IV 期患者的 3 年全因死亡率的风险比。
总队列和 IV 期队列分别包括 12965 例和 635 例患者。HER2 低表达患者在两个队列中均占一半以上（总队列中占 59%，IV 期队列中占 53%）。与 IHC 0 患者相比，HER2 低表达患者更有可能患有激素受体（HR）阳性疾病。在 IV 期队列中，HER2 低表达患者更有可能是黑人（26%比 IHC 0 患者的 16%，p=0.0159）。在两个队列中，HER2 低表达患者的住院率略高。IV 期患者中，HER2 低表达与 IHC 0 患者之间的生存率无差异。
针对 HER2 低表达乳腺癌的新治疗选择可能会对人群水平产生重大影响，特别是对 IV 期疾病患者。鉴于我们队列中观察到 HER2 低表达与 IHC 0 患者之间存在种族差异，为确保 HER2 低转移性乳腺癌患者新治疗指南的公平采用，需要开展基于研究和实践的努力。
