High post‐chemotherapy TIL and increased CD4+TIL are independent prognostic factors of surgically resected NSCLC following neoadjuvant chemotherapy

Neoadjuvant chemotherapy (NCT) has significantly improved the overall survival of patients with operable non‐small cell lung cancer (NSCLC). Chemotherapy can remodel the tumor immune microenvironment (TIME) and has an important influence on antitumor immunity. For patients who underwent surgery for resected NSCLC following NCT (NCT‐NSCLC), a prognostic value comparison between naïve and post‐chemotherapy TIME is absent. We enrolled 89 patients with NCT‐NSCLC in this study; the tumor‐infiltrating lymphocyte (TIL), CD4+TIL, and CD8+TIL levels in naïve and post‐chemotherapy tumor tissues were detected using immunohistochemistry staining and divided into high and low groups. Kaplan–Meier analysis revealed that major pathology response, pathological tumor, node, and metastasis stage post‐NCT (ypTNM), high post‐chemotherapy TIL, high post‐chemotherapy CD8+TIL, low naïve CD4+TIL, low naïve CD4+/CD8+TIL ratio, and increased CD4+TIL levels post‐chemotherapy were favorable prognostic factors in patients with NCT‐NSCLC. Multivariate Cox analysis found that ypTNM, high post‐chemotherapy TIL, and increased CD4+TIL levels post‐chemotherapy were independent prognostic factors in patients with NCT‐NSCLC. These results indicate that a TIME remodeled by chemotherapy plays an important role in antitumor immunity and has a better prognostic value than the naïve TIME.