Division of Pathology, Singapore General Hospital, Singapore.
Division of Pathology, Singapore General Hospital, Singapore.
Ann Diagn Pathol. 2022 Jun;58:151935. doi: 10.1016/j.anndiagpath.2022.151935. Epub 2022 Mar 18.
The study aimed to evaluate the impact of the updated 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on Human Epidermal Growth Factor Receptor 2 (HER2) testing in invasive breast cancer compared with previous 2013 guidelines. Between Jan 2014 and May 2020, 3364 consecutive invasive breast carcinomas with concurrent HER2 immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH) results were retrospectively reviewed for HER2 status. Both 2013 and 2018 testing criteria were applied to establish the HER2 status. The testing algorithms involved testing of invasive breast carcinomas by IHC, with equivocal results being reflexed to FISH assays. Concordance rate improved from 92.7% to 94.1% in the non-equivocal IHC cases with the 2018 guidelines. Comparing 2013 versus 2018 criteria, HER2 non-amplified cases increased significantly from 73.7% (n = 2478) to 76.8% (n = 2585), HER2 amplified cases remained similar from 23.4% (n = 789) to 23.2% (n = 779) while equivocal cases decreased from 2.9% (n = 97) to 0% with the new guidelines. Thus, 107 cases (3.2%) were reclassified from HER2 equivocal (n = 97) and amplified (n = 10) to non-amplified with the updated 2018 guidelines. Under the 2018 criteria, a total of 259 cases (7.7%) belonged to the uncommon categories (groups 2 to 4), with group 3 being the most frequent (4.6%), followed by group 4 (2.9%) and group 2 (0.2%). Implementation of 2018 guidelines resulted in a significant increase in HER2 non-amplified cases, mainly due to the abolishment of the equivocal FISH group. This has helped resolve the clinical practice dilemma by providing a more definitive HER2 gene status.
本研究旨在评估与之前的 2013 年指南相比，2018 年美国临床肿瘤学会/美国病理学家学院（ASCO/CAP）更新的人表皮生长因子受体 2（HER2）检测对浸润性乳腺癌的影响。2014 年 1 月至 2020 年 5 月，回顾性分析了 3364 例连续的伴有 HER2 免疫组化（IHC）和荧光原位杂交（FISH）结果的浸润性乳腺癌，以评估 HER2 状态。应用 2013 年和 2018 年的检测标准来确定 HER2 状态。检测算法包括通过 IHC 检测浸润性乳腺癌，结果不确定者进行 FISH 检测。在 2018 年指南下，非不确定 IHC 病例的一致性率从 92.7%提高到 94.1%。与 2013 年标准相比，HER2 非扩增病例从 73.7%（n=2478）显著增加到 76.8%（n=2585），HER2 扩增病例从 23.4%（n=789）保持相似到 23.2%（n=779），而不确定病例从 2.9%（n=97）减少到 0%。因此，107 例（3.2%）根据更新的 2018 年指南，由 HER2 不确定（n=97）和扩增（n=10）重新分类为非扩增。根据 2018 年的标准，共有 259 例（7.7%）属于不常见类别（第 2 至 4 组），其中第 3 组最常见（4.6%），其次是第 4 组（2.9%）和第 2 组（0.2%）。实施 2018 年指南导致 HER2 非扩增病例显著增加，主要是由于取消了不确定的 FISH 组。这有助于通过提供更明确的 HER2 基因状态来解决临床实践中的困境。
