The development of a nomogram to predict post-radiation necrosis in nasopharyngeal carcinoma patients: a large-scale cohort study

Objective: This study aimed to establish a nomogram to predict the risk of post-radiation necrosis in nasopharyngeal carcinoma (NPC) patients. Background: This study was performed to identify influencing factors for developing post-radiation necrosis, and to establish an effective nomogram model to predict individual risks in NPC patients. Methods: 7144 NPC patients receiving radical radiotherapy from 2007 to 2012 were involved in the study, and 207 of them developed nasopharyngeal necrosis (NPN). The clinical characteristics and baseline laboratory results were collected and analyzed. Independent predictive factors were selected using the Cox proportional model and incorporated into the nomogram. The receiver operating characteristic curve and the calibration curve were used to verify discrimination and calibration. Results: The experience of re-irradiation contributed most to the occurrence of NPN (HR, 15.56, 95% CI 10.84–22.35, p<0.001). Clinical factors including age, pathology type, history of diabetes, and original T stage were independent predictors of NPN. Factors reflecting patients’ baseline nutritional and inflammatory status such as hemoglobin, albumin, and C-reactive protein were also significantly associated with the development of NPN. With all independent predictive factors incorporated, a nomogram was generated, and it showed excellent discrimination and calibration. Conclusion: This study was the first large-scale cohort study focusing on the development of NPN and established a nomogram to predict its occurrence based on the clinical and laboratory indicators. The nomogram demonstrated good discriminative capacity and satisfactory agreement, which would offer valuable clues for clinicians to distinguish the high-risk NPN population and maintain close surveillance.