Department of Pathology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82, Gumi-ro 173 Beon-gil, Bundang-gu, Seongnam, Gyeonggi, 13620, Republic of Korea.
Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Gyeonggi, Republic of Korea.
Breast Cancer. 2024 Jul;31(4):705-716. doi: 10.1007/s12282-024-01585-3. Epub 2024 Apr 21.
Human epidermal growth factor receptor 2 (HER2)-low status has recently gained attention because of the potential therapeutic benefits of antibody-drug conjugates (ADCs) in breast cancer patients. We aimed to investigate the concordance of HER2 status between core needle biopsy (CNB) and subsequent surgical resection specimens focusing on the HER2-low status.
This retrospective study was conducted in 1,387 patients with invasive breast cancer whose HER2 status was evaluated in both CNB and surgical resection specimens. The discordance rates between CNB and surgical resection specimens and the clinicopathological features associated with HER2 status discordance were analyzed.
The overall concordance rates of HER2 status between CNB and surgical resection specimens were 99.0% (κ = 0.925) for two-group classification (negative vs. positive) and 78.5% (κ = 0.587) for three-group classification (zero vs. low vs. positive). The largest discordance occurred in CNB-HER2-zero cases with 42.8% of them reclassified as HER2-low in surgical resection. HER2 discordance was associated with lower histologic grade, tumor multiplicity, and luminal A subtype. In multivariate analysis, tumor multiplicity and estrogen receptor (ER) positivity were independent predictive factors for HER2-zero to low conversion.
Incorporation of HER2-low category in HER2 status interpretation reduces the concordance rate between CNB and surgical resection specimens. Tumor multiplicity and ER positivity are predictive factors for conversion from HER2-zero to HER2-low status. Therefore, HER2 status should be re-evaluated in resection specimens when considering ADCs in tumors exhibiting multiplicity and ER positivity.
人表皮生长因子受体 2（HER2）低状态最近受到关注，因为抗体药物偶联物（ADC）在乳腺癌患者中的潜在治疗益处。我们旨在研究核心针活检（CNB）和随后的手术切除标本中 HER2 状态的一致性，重点关注 HER2 低状态。
本回顾性研究纳入了 1387 例浸润性乳腺癌患者，其 HER2 状态在 CNB 和手术切除标本中均进行了评估。分析了 CNB 和手术切除标本之间的 HER2 状态不一致率以及与 HER2 状态不一致相关的临床病理特征。
CNB 和手术切除标本之间 HER2 状态的总体一致性率为 99.0%（κ=0.925）用于两组分类（阴性与阳性）和 78.5%（κ=0.587）用于三组分类（零与低与阳性）。最大的不一致发生在 CNB-HER2-零病例中，其中 42.8%的病例在手术切除中重新分类为 HER2 低。HER2 不一致与组织学分级较低、肿瘤多发性和 luminal A 亚型有关。多变量分析显示，肿瘤多发性和雌激素受体（ER）阳性是 HER2-零到低转换的独立预测因素。
在 HER2 状态解释中纳入 HER2 低类别会降低 CNB 和手术切除标本之间的一致性率。肿瘤多发性和 ER 阳性是从 HER2-零到 HER2 低状态转换的预测因素。因此，在考虑多发性肿瘤和 ER 阳性的 ADC 时，应在切除标本中重新评估 HER2 状态。
