Effectiveness and mechanisms of lymphocytes at different time points in predicting consolidation immunotherapy following adaptive chemoradiotherapy in locally advanced non-small cell lung cancer

Objective: To investigate the prognostic value of lymphocytes and their subsets at different stages of chemoradiotherapy and consolidation immunotherapy in patients with locally advanced non-small cell lung cancer (NSCLC). Methods: This retrospective analysis enrolled 139 patients with stage III NSCLC (median age 69 years; 95% male; 84.17% squamous cell carcinoma) who received adaptive chemoradiotherapy (CRT) and consolidation anti-PD-1 therapy (sintilimab). Paired samples t-tests were performed to evaluate differences in absolute lymphocyte counts (ALCs) at three time points: before radiotherapy, at the 20th fraction of radiotherapy, and 1 month after radiotherapy. Additionally, paired t-tests were used to compare lymphocyte subsets between the pre-radiotherapy period and 1 month post-radiotherapy. Univariate and multivariate Cox proportional hazards regression analyses were conducted to identify factors influencing progression-free survival (PFS) and overall survival (OS). The Kaplan-Meier analysis was employed to assess PFS and OS in patients stratified according to independent predictive factors associated with OS. Results: /L had significantly longer OS. Significant differences were also observed in CD4+ and CD8+ counts, as well as the CD8/CD4 ratio, between pre-radiotherapy and 1 month post-radiotherapy (p < 0.05). The Kaplan-Meier analysis further showed that patients with higher CD8+ T-cell counts at 1 month post-radiotherapy had significantly longer OS (p < 0.05). Conclusion: In patients with locally advanced NSCLC receiving chemoradiotherapy followed by consolidation immunotherapy, higher ALCs and elevated CD8+ T-cell counts at 1 month post-chemoradiotherapy are associated with improved overall survival.