Analysis of chemoimmunotherapy and inflammatory indices in stage III unresectable lung squamous cell carcinoma

OBJECTIVE: This study aimed to investigate the impact of the treatment duration, initiation timing, and inflammatory factors on immunotherapy maintenance in patients with stage III unresectable lung squamous cell carcinoma. METHODS: A retrospective analysis was conducted on 100 patients with stage III unresectable lung squamous cell carcinoma who received comprehensive treatment consisting of induction chemotherapy followed by concurrent chemoradiotherapy and consolidation immunotherapy (i.e., the "induction + concurrent chemoradiotherapy + consolidation immunotherapy" regimen) between January 2019 and December 2022. The analysis focused on treatment efficacy and prognostic factors. All statistical analyses were performed using SPSS software (version 25.0). Survival analysis was conducted using the Kaplan-Meier method, with between-group comparisons assessed by the Log-rank test (for univariate analysis, significance level α = 0.10). Multivariate analysis was performed using the Cox proportional hazards regression model (significance level α = 0.05). Optimal cutoff values for the neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) were determined using SPSS, and their sensitivity and specificity were calculated. Subsequently, based on these optimal cutoff values, patients were stratified into high- and low-value groups, thereby converting these continuous variables into categorical variables for further analysis. RESULTS: Among the 100 patients who received induction chemotherapy followed by concurrent chemoradiotherapy and consolidation immunotherapy, the 1-, 3-, and 5-year overall survival (OS) rates were 88.8%, 61.6%, and 43.6%, respectively. The corresponding 1-, 3-, and 5-year progression-free survival (PFS) rates were 74.6%, 45.3%, and 39.7%. Until the last follow-up, disease recurrence or metastasis occurred in 46 cases, including 15 cases of local recurrence, 16 cases of distant metastasis (8 with intracranial metastasis, 5 with liver metastasis, and 3 with bone metastasis), and 15 cases of regional lymph node metastasis (involving station 2, 4, 7 and supraclavicular lymph nodes).Univariate analysis identified TNM stage (p = 0.002), maintenance immunotherapy duration (p < 0.001), and interval between immunotherapy initiation and the last chemotherapy (p = 0.054) as factors associated with overall survival (OS).Multivariate Cox analysis confirmed that TNM stage (p = 0.03) and maintenance immunotherapy duration (p = 0.005) remained independently associated with OS. For progression-free survival (PFS), univariate analysis showed that the maintenance immunotherapy duration (p = 0.012) and TNM stage (p < 0.001) were significantly associated with PFS. Multivariate Cox analysis further demonstrated that both TNM stage (p = 0.01) and the maintenance immunotherapy duration (p = 0.034) retained independent associations with PFS. CONCLUSION: For patients with locally advanced lung squamous cell carcinoma, the comprehensive regimen of induction chemotherapy followed by concurrent chemoradiotherapy and consolidation immunotherapy-initiating consolidation immunotherapy two weeks after completing concurrent chemoradiotherapy and continuing for two years-yielded favorable outcomes, with efficacy comparable to that reported in previous studies. In this cohort, more advanced clinical stage, higher neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), and lower lymphocyte-to-monocyte ratio (LMR) were associated with poorer prognosis. The prognostic prediction model constructed based on TNM stage, NLR, PLR, and LMR demonstrated good predictive performance and clinical utility, representing a simple, economical, and effective tool worthy of further exploration for guiding clinical decision-making.