Establishment of a Prognostic Nomogram for Elderly Patients with Limited-Stage Small Cell Lung Cancer Receving Radiotherapy

Background: The present study explored the risk factors associated with radiotherapy in seniors diagnosed with limited-stage small cell lung cancer (LS-SCLC) to construct and validate a prognostic nomogram. Methods: The study retrospectively included 137 elderly patients with LS-SCLC who previously received radiation therapy. Univariate and multivariate COX analyses were conducted to identify independent risk factors and determine optimal cut-off values. Kaplan-Meier survival curves and nomograms were constructed to predict survival. Calibration and receiver operating characteristic (ROC) curves were used to evaluate the accuracy and consistency of the nomogram. Results: Illness Rating Scale-Geriatric (CIRS-G) score, treatment strategy, lymphocyte-to-monocyte ratio (LMR), white blood cell-to-monocyte ratio (WMR), and prognostic nutritional index (PNI) were discovered to be independent prognostic factors. Based on the findings of our multivariate analysis, a risk nomogram was developed to assess patient prognosis. Internal bootstrap resampling was utilized to validate the model, and while the accuracy of the AUC curve at 1 year was modest at 0.657 (95% CI: 0.458-0.856), good results were achieved in predicting 3- and 5-year survival with AUCs of 0.757 (95% CI: 0.670-0.843) and 0.768 (95% CI: 0.643-0.893), respectively. Calibration curves for 1-, 3-, and 5-year overall survival probabilities demonstrated good cocsistency between expected and actual outcomes. Conclusion: Patients with concurrent chemoradiotherapy,CIRS-G score > 5 points and low PNI, WMR and LMR correlated with poor prognosis. The nomogram model developed based on these factors demonstrated good predictive performance and provides a simple, accessible, and practical tool for clinicians to guide clinical decision-making and study design.