Risk Factors of Malnutrition in Nasopharyngeal Carcinoma Patients Undergoing Radiotherapy and Construction of a Predictive Model.

Malnutrition is a common and serious complication in patients undergoing radiotherapy for nasopharyngeal carcinoma (NPC). This study aimed to identify risk factors for malnutrition and to construct and validate a predictive model to aid early detection. A total of 158 NPC patients treated with radiotherapy at the Second Affiliated Hospital of Hainan Medical University between March 2023 and November 2024 were retrospectively analyzed. Demographic, clinical, and biochemical data were collected, and nutritional status was assessed using the Patient-Generated Subjective Global Assessment (PG-SGA). Patients were classified as malnourished or non-malnourished, and potential predictors were evaluated using Least Absolute Shrinkage and Selection Operator (LASSO) regression followed by multivariable logistic regression. Among all patients, 118 (74.7%) developed malnutrition. Nutritional support and total protein were identified as independent protective factors, while dysphagia emerged as an independent risk factor. A nomogram incorporating these factors demonstrated strong discriminatory ability (AUC=0.964), good calibration, and clinical utility across threshold probabilities of 0.2-1.0 as shown by decision curve analysis. These findings indicate that malnutrition is highly prevalent in NPC patients undergoing radiotherapy and highlight the importance of nutritional support and protein status in reducing risk. The developed model offers a practical tool for early screening and targeted intervention in clinical practice.