Tumor immune microenvironment predicts the pathologic response of neoadjuvant chemoimmunotherapy in non–small-cell lung cancer

The clinical outcome of resectable non–small-cell lung cancer (NSCLC) patients receiving neoadjuvant chemoimmunotherapy is good but varies greatly. In addition, the pathological response after neoadjuvant chemoimmunotherapy is significantly associated with survival outcomes. The aim of this retrospective study was to identify which population of patients with locally advanced and oligometastatic NSCLC has a favorable pathological response after neoadjuvant chemoimmunotherapy. NSCLC patients treated with neoadjuvant chemoimmunotherapy were enrolled between February 2018 and April 2022. Data on clinicopathological features were collected and evaluated. Multiplex immunofluorescence was performed on pre-treatment puncture specimens and surgically resected specimens. In total, 29 patients with stages III and IV locally advanced or oligometastatic NSCLC who received neoadjuvant chemoimmunotherapy and R0 resection were enrolled. The results showed that 55% (16/29) of patients had a major pathological response (MPR) and 41% (12/29) of patients had a complete pathological response (pCR). In the stroma area of the pre-treatment specimen, the higher infiltration of CD3⁺PD-L1⁺ tumor-infiltrating lymphocytes (TILs) and the lower infiltration of CD4⁺ and CD4⁺FOXP3⁺ TILs were more likely to appear in patients with pCR. However, in the tumor area, the higher infiltration of CD8⁺ TILs was more likely to appear in patients with non-MPR. In the post-treatment specimen, we found increased infiltration of CD3⁺CD8⁺, CD8⁺GZMB⁺, and CD8⁺CD69⁺ TILs and decreased infiltration of PD-1⁺ TILs both in the stroma and tumor areas. Neoadjuvant chemoimmunotherapy achieved an MPR rate of 55% and induced greater immune infiltration. In addition, we observed that the baseline TILs and their spatial distribution correlate to the pathological response.