Supplementary Material for: Implementation of PD-L1 22C3 IHC pharmDx^TM in Cell Block Preparations of Lung Cancer: Concordance with Surgical Resections and Technical Validation of CytoLyt® Prefixation

<b><i>Background:</i></b> Programmed death ligand-1 (PD-L1) assessed by immunohistochemistry (IHC) is used as biomarker for pembrolizumab therapy in advanced stage lung cancer patients. However, data permitting direct performance comparison between cytology and surgical specimen types are limited since both specimens from a single tumor site are infrequently available. In addition, alcohol fixation used with cytology specimens requires technical validation of the PD-L1 IHC assay before clinical use. We here report our experience with implementation of the PD-L1 22C3 IHC pharmDx^TM assay for cytologic samples at a large tertiary cancer center. <b><i>Study Design:</i></b> Archival formalin-fixed (FF), paraffin-embedded cell blocks (CBs) and subsequent lung tumor resections (LTRs) from the same anatomical site were used for a direct comparison of PD-L1 tumor proportion scores (TPSs). TPS values were independently determined by one surgical lung pathologist and two cytopathologists blinded to the specimen pairs. An interim analysis was performed to facilitate the pooling of expertise among observers. After PD-L1 22C3 IHC pharmDx^TM implementation for FF cytology specimens, dual-processed samples were used for a prospective technical validation of CytoLyt® prefixation (CF). Digital image analysis was performed for a subset of dual-processed specimens. <b><i>Results:</i></b> Eighty-one CBs and LTRs were included for comparison of the specimen types. PD-L1 assessment in CBs had an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 88.9/72.8, 66.7/73.5, 95.2/72.3, 80.0/65.8, and 90.9/79.1% for the ≥50/≥1% cutoff, respectively. The intraclass correlation coefficient was 0.84 (95% confidence interval [CI]: 0.76, 0.90), and it improved after interim analysis (before: 0.79 and after: 0.92). The overall concordance between CF and FF for the categories defined by the ≥50/≥1% cutoff values was 90.4% (95% CI: 79.0, 96.8). Similar assay performance was confirmed by digital analysis. <b><i>Conclusions:</i></b> PD-L1 22C3 IHC pharmDx^TM shows good reliability if used with CB preparations. CF does not impact assay results significantly. Clinical validation with outcome data is needed, and digital methods of assessment should be further investigated.

<b><i>背景：</i></b> 经免疫组织化学（immunohistochemistry, IHC）检测的程序性死亡配体1（Programmed death ligand-1, PD-L1），是晚期肺癌患者接受帕博利珠单抗（pembrolizumab）治疗的常用生物标志物。然而，由于同一肿瘤部位同时获取细胞学标本与手术标本的情况较为少见，可直接对比两类标本检测性能的相关数据十分有限。此外，细胞学标本常规采用的酒精固定方案，需在临床应用前完成PD-L1免疫组化检测试剂的技术验证。本研究报告了本大型三级癌症医疗中心应用PD-L1 22C3免疫组化pharmDx™检测试剂开展细胞学样本检测的实践经验。<b><i>研究设计：</i></b> 本研究选取来自同一解剖部位的存档福尔马林固定（formalin-fixed, FF）石蜡包埋细胞块（paraffin-embedded cell blocks, CBs）及后续肺肿瘤切除术标本（lung tumor resections, LTRs），直接对比二者的PD-L1肿瘤比例评分（tumor proportion scores, TPSs）。由1名外科肺病理医师及2名对标本配对信息设盲的细胞病理医师，独立完成TPS值的判读。为整合观察者间的专家意见，本研究开展了中期分析。在针对福尔马林固定细胞学标本完成PD-L1 22C3免疫组化pharmDx™试剂的应用验证后，本研究采用双处理样本，对CytoLyt®前置固定（CytoLyt prefixation, CF）开展前瞻性技术验证。同时，本研究对部分双处理标本实施了数字图像分析。<b><i>结果：</i></b> 本研究共纳入81对细胞块与肺肿瘤切除术标本，用于两类标本的性能对比。针对≥50%/≥1%的截断值，细胞块的PD-L1检测的准确性、灵敏度、特异性、阳性预测值及阴性预测值分别为88.9%/72.8%、66.7%/73.5%、95.2%/72.3%、80.0%/65.8%及90.9%/79.1%。组内相关系数为0.84（95%置信区间[confidence interval, CI]：0.76~0.90），且经中期分析后该系数显著提升（中期分析前为0.79，分析后为0.92）。基于≥50%/≥1%截断值划分的分类中，CytoLyt®前置固定样本与福尔马林固定样本的总体一致性为90.4%（95%置信区间：79.0~96.8）。数字图像分析结果亦证实了相似的检测性能。<b><i>结论：</i></b> PD-L1 22C3免疫组化pharmDx™试剂应用于细胞块标本时，展现出良好的检测可靠性。CytoLyt®前置固定不会对检测结果造成显著影响。未来仍需结合预后数据开展临床验证，并进一步探索数字化评估方法的应用价值。

搜集汇总

背景与挑战

背景概述

该数据集是肺癌研究中PD-L1 22C3 IHC pharmDxTM在细胞块制备中应用的补充材料，重点比较了细胞块与手术切除标本的PD-L1肿瘤比例评分一致性，并验证了CytoLyt®前缀处理的技术效果。研究结果显示，细胞块中PD-L1评估在≥50%和≥1%截断值下具有较高准确性（如准确性达88.9%和72.8%），且前缀处理不影响检测结果，表明该方法在临床应用中可靠，但需进一步临床验证和数字评估方法研究。