Pathological complete response to neoadjuvant chemoimmunotherapy correlates with peripheral blood immune cell subsets and metastatic status of mediastinal lymph nodes (N2 lymph nodes) in non-small cell lung cancer

Neoadjuvant chemo-immunotherapy has got clinical benefits in parts of resectable non-small cell lung cancer (NSCLC) patients. The factors affecting the pathological response of NSCLC remain controversial.A retrospective study of 59 patients with resectable stage IIA-IIIB NSCLC who were treated with neoadjuvant chemo-immunotherapy was performed. The clinical characteristics were analyzed in the pathological complete response (pCR) group and the non-pCR group. The immune cell subsets in peripheral blood were detected by flow cytometry.By analyzing the correlation between pathological response and clinical characteristics, we found that patients with N2 metastases were less effective in neoadjuvant chemo-immunotherapy (P = 0.001). Programmed death-ligand 1 (PD-L1) expression and treatment cycle were not related to pathological response (P > 0.05). Lower levels of total T cells, Th cells, and higher levels of NK cells in baseline were associated with pCR (P < 0.05). And during neoadjuvant chemo-immunotherapy, total T cells and activated T cells were significantly increased in patients with pCR (P < 0.05).The peripheral blood immune cell subsets and lymph node status were closely related to pathological response in patients with neoadjuvant chemo-immunotherapy. No significant correlation was found between pathologic response and PD-L1 expression.