Age and CIRS-G for risk stratification in elderly esophageal squamous cell carcinoma patients receiving definitive chemoradiotherapy.

OBJECTIVE: To identify prognostic factors in elderly squamous cell carcinoma (ESCC) patients receiving definitive chemoradiotherapy (dCRT) and construct a prognostic risk stratification model for identifying high-risk subgroups among elderly patients. METHODS: ESCC patients aged ≥ge years receiving dCRT were enrolled. Baseline Cumulative Illness Rating Scale-Geriatrics (CIRS-G), Geriatric Nutrition Risk Index (GNRI), Systemic Immune-Inflammation Index (SII), clinical characteristics and adverse events were collected. Cox regression identified independent prognostic factors, with proportional hazards assessed by Schoenfeld residual tests and 95% confidence intervals validated by 1000 bootstrap resamples. Restricted cubic spline (RCS) curves evaluated potential cutoff values. Survival was analyzed by Kaplan-Meier method and compared by log-rank test. RESULTS: 88 patients were enrolled. Multivariate analysis identified age (HR 1.047, 95% CI 1.000-1.095) and CIRS-G (HR 1.179, 95% CI 1.014-1.376) as independent predictors of OS, whereas GNRI (HR 0.964, 95% CI 0.932-0.995) independently predicted PFS. Schoenfeld tests confirmed proportional hazards (all P > 0.05), with bootstrap resampling supporting coefficient stability. Cutoffs were set at 75 years for age, 7 for CIRS-G, and 98 for GNRI. A prognostic score combining age and CIRS-G stratified patients into low-risk (0-1) and high-risk (2) groups, with high-risk patients showing significantly inferior OS. GNRI ≥98 correlated with prolonged PFS versus <98. The high-risk group had higher neutropenia/leukopenia (15.0% vs. 6.3%) and pneumonitis (5.0% vs. 2.1%), with exclusive thrombocytopenia/anemia (2.5% each). CONCLUSIONS: A composite risk score (age ≥75 years plus CIRS-G ≥7) identified a high-risk subgroup with poor OS. The optimal therapeutic strategy for this subgroup warrants prospective interventional trials.