To investigate the predictive value of peripheral blood inflammatory markers for major pathological response (MPR) in patients with locally advanced nonsmall cell lung cancer (NSCLC) receiving neoadjuvant immunochemotherapy.

A total of 104 patients with locally advanced NSCLC who received neoadjuvant immunochemotherapy at our hospital from February 2022 to January 2025 were retrospectively enrolled. Based on postoperative pathological findings, MPR were divided into the observation group (63 cases) and non MPR were the control group (41 cases). Clinical data, as well as pre and posttreatment neutrophiltolymphocyte ratio (NLR), platelettolymphocyte ratio (PLR), systemic immuneinflammation index (SII), and prognostic nutritional index (PNI), were collected. The change values (Δ=posttreatment-pretreatment) were calculated. LASSO regression was used for variable selection, and multivariate Logistic regression was performed to identify independent factors associated with MPR and to construct a nomogram. The association between dynamic inflammation score and eventfree survival (EFS) was analyzed using the KaplanMeier method with the Logrank test.

After treatment, the observation group showed significantly lower ΔNLR[-0.65(-1.71, -0.27) vs. 0.58 (0.22, 1.94), Z= -5.053, P<0.001], ΔPLR[-48.13 (-102.80, -12.83) vs. 26.22 (-16.87, 60.70), Z=-4.660, P<0.001], and ΔSII[-225.54 (-411.09, -83.77) vs. 380.83 (104.52, 538.33), Z=-5.768, P<0.001], and significantly higher ΔPNI[0.98(-1.80, 3.71) vs. -1.63 (-7.15, 0.79), Z=-5.236, P<0.001] than the control group. Multivariate Logistic regression revealed that pathological subtype (adenocarcinoma vs. squamous cell carcinoma: OR=0.127, 95%CI: 0.021~0.769, P=0.025), histological differentiation (poorly differentiated vs. moderately differentiated: OR=0.022, 95%CI: 0.002~0.294, P=0.004), ΔNLR(OR=0.518, 95%CI: 0.299~0.898, P=0.019), ΔSII (OR=0.996, 95%CI: 0.993~0.998, P=0.002), and ΔPNI (OR=1.514, 95%CI: 1.146~2.001, P=0.004) were independent factors for MPR. The nomogram model yielded an AUC of 0.95 (95%CI: 0.91~0.99) for predicting MPR. The HosmerLemeshow test indicated good model calibration (χ²=6.610, P=0.579), and the decision curve analysis demonstrated a high net clinical benefit within the risk threshold range of 0.10~0.92. Using the median dynamic inflammation score of 0.76 as the cutoff, the lowscore group (52 cases) had a significantly shorter median EFS of 22 months compared with 36 months in the highscore group (52 cases) (Logrank χ²= 30.989, P<0.001).

Dynamic changes in ΔNLR, ΔSII, and ΔPNI before and after neoadjuvant immunochemotherapy are predictive biomarkers for postoperative MPR in patients with locally advanced NSCLC. The nomogram combining these markers with pathological subtype and histological differentiation exhibits excellent discriminative ability, calibration, and clinical net benefit, which may help preoperatively predict pathological response to neoadjuvant immunochemotherapy and provide a reference for longterm recurrence risk stratification.