Abstract
Immune checkpoint inhibitors (ICIs) combined with platinum-containing chemotherapy are recommended as the standard first-line treatment for non-small cell lung cancer (NSCLC). However, specific prognostic markers for this combination therapy are yet to be identified. Evaluation of circulating tumor cells (CTCs) and cell surface programmed death-ligand 1 (PD-L1) exhibits potential in predicting the efficacy of the aforementioned combination therapy. Thus, the present study aimed to evaluate the prognostic value of CTC PD-L1 testing and other clinical characteristics in patients with NSCLC treated with combination therapy as first-line treatment. In total, 40 patients with advanced NSCLC were included in the present study, and all patients underwent CTC PD-L1 testing at initial diagnosis to determine the association between CTC PD-L1 and tissue PD-L1. The prognostic value of CTC PD-L1 and the baseline characteristics of 26 patients with NSCLC were analyzed, and the prognostic values of changes in CTC PD-L1 and baseline characteristics during 6 months of treatment were further explored. Results of the present study demonstrated that there was no association between CTC PD-L1 and tissue PD-L1 levels. After 6 months of combination therapy, tumor shrinkage, CYFA19 levels and treatment maintenance were associated with progression-free survival (PFS) of patients. Notably, CTC PD-L1 and tissue PD-L1 levels, TNM stage, nutritional score, inflammation score and other blood indicators were not associated with PFS. In conclusion, the evaluation of CTCs and CTC PD-L1 suggested that undetectable CTCs at 6 months of NSCLC treatment are associated with a good prognosis. In addition, negative CTC PD-L1 expression may change to positive CTC PD-L1 expression in line with disease progression, and this may be indicative of poor prognosis.