Background Programmed death ligand-1 (PD-L1) expression on circulating tumor cells (CTCs) has been suggested to provide prognostic information in non-small cell lung cancer (NSCLC), but consensus relative to treatment outcomes is lacking. We conducted the first comprehensive meta-analysis exploring its potential as a prognostic and predictive marker, and assessed the concordance between PD-L1 + CTCs and paired tumor tissue in NSCLC patients. Method A comprehensive search was applied to PubMed and EMBASE to identify 26 studies that evaluated PD-L1 + CTCs and their association with survival outcomes in 1236 NSCLC patients. Results The meta-analysis estimated a mean PD-L1 + CTCs detection rate of 61% (95% CI, 49–72). Subgroup analysis based on treatment showed that PD-L1 + CTCs was not significantly associated with better overall survival (OS) in NSCLC patients treated with immune checkpoint inhibitors (ICIs) (Hazard Ratio (HR) = 0.96, 95% CI, 0.35–2.65, P = 0.944), but was predictive of worse OS in those treated with other therapies (HR = 2.11, 95% CI, 1.32–3.36, P = 0.002). Similarly, PD-L1 + CTCs was not significantly associated with superior progressing free survival (PFS) in NSCLCs treated with ICIs (HR = 0.67, 95% CI, 0.41–1.09, P = 0.121), but was significantly associated with shorter PFS in patients treated with other therapies (HR = 1.91, 95% CI, 1.24–2.94, P = 0.001). The overall estimate for the concordance between PD-L1 expression on CTCs and tumor cells was 63% (95% CI, 44–80). Conclusion The average detection rate of PD-L1 + CTCs was comparable to the rate of PD-L1 expression in NSCLC tumors. There was a trend towards better PFS in ICI-treated NSCLC patients with PD-L1 + CTCs. Larger longitudinal studies on the association of PD-L1 + CTCs with clinical outcomes in NSCLC patients treated with ICIs are warranted.

中文翻译：

---

循环肿瘤细胞 PD-L1 表达及其与非小细胞肺癌临床结果关联的荟萃分析

背景 循环肿瘤细胞 (CTC) 上的程序性死亡配体-1 (PD-L1) 表达被认为可以提供非小细胞肺癌 (NSCLC) 的预后信息，但缺乏与治疗结果相关的共识。我们进行了首次综合荟萃分析，探索其作为预后和预测标记物的潜力，并评估了 NSCLC 患者中 PD-L1 + CTC 与配对肿瘤组织之间的一致性。方法 通过 PubMed 和 EMBASE 进行全面检索，确定了 26 项研究，这些研究评估了 PD-L1 + CTC 及其与 1236 名 NSCLC 患者生存结果的关系。结果 荟萃分析估计 PD-L1 + CTC 的平均检出率为 61%（95% CI，49-72）。基于治疗的亚组分析表明，PD-L1 + CTC 与接受免疫检查点抑制剂 (ICIs) 治疗的 NSCLC 患者的总生存期 (OS) 改善并无显着相关性（风险比 (HR) = 0.96，95% CI，0.35–2.65） ，P = 0.944），但可以预测接受其他疗法治疗的患者 OS 较差（HR = 2.11，95% CI，1.32–3.36，P = 0.002）。同样，PD-L1 + CTC 与接受 ICI 治疗的 NSCLC 中优越的无进展生存期 (PFS) 没有显着相关（HR = 0.67，95% CI，0.41–1.09，P = 0.121），但与接受 ICI 治疗的 NSCLC 中较短的 PFS 显着相关。接受其他疗法治疗的患者（HR = 1.91，95% CI，1.24–2.94，P = 0.001）。CTC 和肿瘤细胞上 PD-L1 表达的一致性总体估计为 63% (95% CI, 44-80)。结论 NSCLC肿瘤中PD-L1+CTC的平均检出率与PD-L1表达率相当。接受 ICI 治疗的 PD-L1 + CTC 的 NSCLC 患者有改善 PFS 的趋势。有必要对 PD-L1 + CTC 与接受 ICI 治疗的 NSCLC 患者的临床结果之间的关联进行更大规模的纵向研究。