Prevalence of malnutrition and its prognostic impact in lung metastasis patients treated with SBRT: insights from NRI, CONUT, NRS, and PNI

Objective Malnutrition is a significant and modifiable prognostic factor in patients with pulmonary metastases undergoing stereotactic body radiotherapy (SBRT). This study evaluated and compared the prognostic utility of four nutritional assessment tools—Nutritional Risk Index (NRI), Controlling Nutritional Status (CONUT), Nutritional Risk Screening 2002 (NRS), and Prognostic Nutritional Index (PNI)—to identify malnutrition patients and inform potential interventions for improving survival. Methods In this retrospective cohort study of 185 patients with pulmonary metastases treated with SBRT, nutritional status was assessed using the NRI, CONUT, NRS, and PNI. The primary endpoint was overall survival (OS). Statistical analyses encompassed survival analysis, subgroup exploration, correlation assessment, and development of an integrated prognostic model. Results Malnutrition prevalence varied: 65.95% (NRI), 63.78% (CONUT), 77.84% (NRS), and 79.46% (PNI) of patients had some nutritional impairment. Multivariable analysis identified CONUT (HR = 1.09) and NRI (HR = 3.99) as independent prognostic factors for OS. An integrated model combining nutritional (CONUT, NRI) and clinical variables showed superior predictive performance (C-index: 0.681) compared to any single tool. Conclusion Malnutrition is highly prevalent and prognostic in SBRT-treated lung metastasis patients. CONUT and NRI are effective for risk stratification. The integrated model offers a superior prognostic tool, supporting the routine integration of these nutritional assessments into clinical practice to identify high-risk patients for timely intervention.