Medical Department, Division of Respiratory Medicine, Azienda Ospedaliero Universitaria Maggiore della Carità di Novara, Novara, Italy.
Department of Translational Medicine, University of Piemonte Orientale, Azienda Ospedaliero Universitaria Maggiore della Carità di Novara, Novara, Italy.
Cancer Cytopathol. 2020 Aug;128(8):580-588. doi: 10.1002/cncy.22292. Epub 2020 May 28.
In advanced non-small cell lung cancer (NSCLC), cytologic specimens from transbronchial needle aspiration (TBNA) or transthoracic needle aspiration are often the only cancer tissue material available for the analysis of programmed death ligand 1 (PD-L1) expression. This study was aimed at assessing the concordance of PD-L1 expression in histologic and cytologic samples and at evaluating interobserver agreement on specimens in this setting.
One hundred and thirty-eight specimens from 60 patients with NSCLC were analyzed. Histologic specimens were represented by endoscopic samples obtained with forceps (biopsies), whereas cytologic specimens were from TBNA and bronchial lavage (BL). PD-L1 expression was quantified with the immunohistochemistry (IHC)-based Ventana SP263 assay. For cytologic specimens, IHC was performed on cell block sections. Two independent pathologists who were blinded to the clinical data evaluated partial or complete membrane IHC staining. Concordance between 2 methods and between 2 pathologists was evaluated with normal and weighted Cohen's κ coefficients, overall agreement, and Bland-Altman plots.
PD-L1 expression was quantified in 138 specimens from 60 patients. Concordance between cytologic and histologic approaches was moderate (κ = 0.56; weighted κ = 0.55). Also, concordance in the biopsy-TBNA and biopsy-BL subgroups was moderate (κ = 0.43 and κ = 0.47, respectively), whereas interobserver agreement was substantial (weighted κ = 0.72). A Bland-Altman plot showed an underestimation in PD-L1 values from cytologic samples in comparison with histologic ones.
The results demonstrate that in the absence of available histologic specimens, PD-L1 positivity in cytologic samples could be a reliable data for the oncologist to consider immune checkpoint inhibitor therapy. However, a comparison of cytologic and histologic samples has shown an underestimation of PD-L1 values in cytologic samples.
在晚期非小细胞肺癌（NSCLC）中，经支气管针吸活检（TBNA）或经胸针吸活检获得的细胞学标本通常是唯一可用于分析程序性死亡配体 1（PD-L1）表达的癌症组织材料。本研究旨在评估组织学和细胞学标本中 PD-L1 表达的一致性，并评估在这种情况下标本的观察者间一致性。
分析了 60 例 NSCLC 患者的 138 份标本。组织学标本代表用钳子（活检）获得的内镜标本，而细胞学标本来自 TBNA 和支气管灌洗（BL）。PD-L1 表达通过免疫组化（IHC）基于 Ventana SP263 检测进行定量。对于细胞学标本，在细胞块切片上进行 IHC。两位独立的病理学家在不知道临床数据的情况下评估了部分或完全膜 IHC 染色。通过正常和加权 Cohen's κ 系数、总一致性和 Bland-Altman 图评估两种方法之间和两位病理学家之间的一致性。
在 60 例患者的 138 份标本中对 PD-L1 表达进行了定量。细胞学和组织学方法之间的一致性为中度（κ=0.56；加权κ=0.55）。此外，活检-TBNA 和活检-BL 亚组之间的一致性也为中度（κ=0.43 和 κ=0.47），而观察者间的一致性为高度（加权κ=0.72）。Bland-Altman 图显示，与组织学标本相比，细胞学标本中的 PD-L1 值存在低估。
结果表明，在没有可用的组织学标本的情况下，细胞学标本中的 PD-L1 阳性可以为肿瘤学家提供可靠的数据，以考虑免疫检查点抑制剂治疗。然而，对细胞学和组织学标本的比较表明，细胞学标本中 PD-L1 值存在低估。
