Predictive value of the systemic immune-inflammation index and geriatric nutritional risk index on the efficacy of immunotherapy and survival prognosis in advanced non-small cell lung cancer: a retrospective study.

[OBJECTIVE] To investigate the predictive value of the systemic immune-inflammation index (SII) and geriatric nutritional risk index (GNRI) for immunotherapy efficacy and survival prognosis in advanced non-small cell lung cancer (NSCLC).

[METHODS] This retrospective study enrolled 152 patients with advanced NSCLC who received immunotherapy. Patients were divided into effective (n = 106) and ineffective (n = 46) groups based on treatment response. Pretreatment SII, GNRI, and programmed cell death-ligand 1 (PD-L1) levels were compared between groups. Multivariate logistc regression identified factors influencing immunotherapy efficacy. Receiver operating characteristic curve analysis evaluated the predictive value of these indicators. Kaplan-Meier method analyzed the relationship between SII, GNRI, and progression-free survival (PFS)/overall survival (OS). Cox regression analyzed their impact on survival and interaction.

[RESULTS] The effective group had significantly lower pretreatment SII but higher GNRI and PD-L1 than the ineffective group (all <0.05). All three indicators significantly influenced immunotherapy efficacy (all <0.05). SII combined with GNRI yielded a higher AUC (0.879) for predicting efficacy than SII alone (0.778), GNRI alone (0.699), or PD-L1 alone (0.707). Patients with high SII (≥418.67) had worse 2-year OS and shorter median PFS/OS than those with low SII (all <0.05). Patients with low GNRI (<97.89) had worse outcomes than those with high GNRI (≥97.89) (all <0.05). SII ≥418.67 and GNRI <97.89 were independent risk factors for poor survival (both <0.05), with significant interaction between them.

[CONCLUSIONS] SII and GNRI are closely associated with immunotherapy efficacy in advanced NSCLC, and their interaction influences patient survival.