Evaluation of tumoral programmed cell death ligand-1 (PD-L1) expression is standard practice for patients with advanced non-small-cell lung cancer (NSCLC) who may be candidates for treatment targeting the programmed cell death-1 (PD-1)/PD-L1 pathway. Currently, all of the commercially available immunohistochemistry assays have been validated for use with histology specimens although, in routine clinical practice, approximately 30-40 % of patients with advanced NSCLC have only cytology specimens available for diagnosis, staging, and biomarker analysis. This systematic review evaluated the success rate, concordance, and clinical utility of using cytology specimens to assess tumor PD-L1 expression levels compared with histology specimens from patients with advanced NSCLC. EMBASE and PubMed database searches identified 142 unique, relevant publications, of which 15 met the inclusion criteria for at least one analysis. In 709 specimens, across seven publications, the proportion of cytology specimens evaluable for PD-L1 testing was 92.0 %. Among nine studies eligible for concordance analysis between cytology and histology specimens at a PD-L1 tumor cell expression cutoff of ≥50 %, overall percentage agreement was 89.7 % (n = 428), 72.0 % for positive percentage agreement (n = 218), and 95.0 % for negative percentage agreement (n = 258); results using a tumor PD-L1 expression cutoff of ≥1 % were similar. Our analyses suggest that using cytology specimens to assess PD-L1 expression is feasible, with good levels of concordance between cytology and histology specimens using PD-L1 tumor cell expression cutoffs of ≥1 % and ≥50 %. In conclusion, there is no convincing evidence that cytology specimens are inadequate or inferior to histology specimens for assessing PD-L1 expression in patients with NSCLC.

中文翻译：

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PD-L1检测的细胞学：系统评价。

对于晚期非小细胞肺癌（NSCLC）患者，评估肿瘤程序性细胞死亡配体1（PD-L1）表达是标准做法，他们可能是靶向程序性细胞死亡1（PD-1）的候选治疗药物/ PD-L1途径。目前，所有可商购的免疫组织化学测定方法均已验证可用于组织学标本，尽管在常规临床实践中，约30-40％的晚期NSCLC患者仅具有可用于诊断，分期和生物标志物分析的细胞学标本。该系统评价与晚期NSCLC患者的组织学样本相比，使用细胞学样本评估肿瘤PD-L1表达水平的成功率，一致性和临床实用性进行了评估。EMBASE和PubMed数据库搜索确定了142个唯一的，相关出版物，其中15个满足至少一项分析的纳入标准。在七个出版物中的709个标本中，可用于PD-L1测试的细胞学标本比例为92.0％。在9项符合PD-L1肿瘤细胞表达截断率≥50％的细胞学和组织学标本一致性分析的研究中，总体百分比一致性为89.7％（n = 428），阳性百分比一致性为72.0％（n = 218），负百分比协议的使用率为95.0％（n = 258）；使用≥1％的肿瘤PD-L1表达截断的结果相似。我们的分析表明，使用细胞学标本评估PD-L1表达是可行的，并且使用PD-L1肿瘤细胞表达临界值≥1％和≥50％的细胞学和组织学标本之间具有良好的一致性。结论，