Abstract
BACKGROUND: The incorporation of immune checkpoint blockade into preoperative regimens has significantly advanced the clinical management of locally advanced non-small cell lung cancer (NSCLC). Standard imaging modalities frequently fall short in assessing actual pathological regression. Our research sought to evaluate circulating tumor cells (CTCs) as an adjunct predictive tool, while uncovering the transcriptomic shifts within the tumor microenvironment that facilitate cellular shedding. METHODS: A prospective cohort of 39 patients with NSCLC received neoadjuvant programmed cell death protein 1 (PD-1) inhibitors combined with platinum-doublet chemotherapy. Preoperative radiographic evaluations using RECIST 1.1 were cross-referenced with final pathological outcomes. Peripheral blood CTCs were enriched and phenotypically characterized via multiparametric immunofluorescence (CK, PD-L1). Bulk RNA-sequencing of residual tissue specimens was performed to identify gene signatures associated with CTC dissemination. RESULTS: The cohort achieved a major pathologic response (MPR) rate of 38.5%, including a pathological complete response (pCR) rate of 23.1%. Preoperative cytokeratin-positive (CK+) CTC burden emerged as a potential independent predictor of pathological non-response (AUC = 0.757), outperforming total CTCs and PD-L1+ CTCs. Crucially, integrating CK+ CTC counts with standard radiographic imaging improved predictive accuracy for pathological outcomes (AUC = 0.79) compared to imaging alone (AUC = 0.54, p = 0.022). Transcriptomic profiling of the residual tumor microenvironment suggested that CTC dissemination may be associated with enhanced proliferative activity, severe local hypoxia and a broad immunological suppression within local microenvironments. CONCLUSIONS: Preoperative CTC monitoring may serve as a promising complementary biomarker to conventional radiographic imaging, with the potential to help resolve predictive ambiguities in neoadjuvant chemoimmunotherapy for NSCLC.