Nasopharyngeal necrosis, Nasopharyngeal carcinoma, Intensity modulated radiation therapy, Dose constraint, Least absolute shrinkage and selection operator logistic regression, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282

Abstract Objectives This study aimed to investigate the incidence of post radiation nasopharyngeal necrosis (PRNN) in primary NPC after intensity modulated radiation therapy (IMRT) and identify the predictors of risk. Methods Data of 5798 NPC patients who received IMRT-based treatment between April 2009 and December 2015 were retrospectively reviewed. PRNN was diagnosed by MRI or nasopharyngoscopy. Dosimetric factors were selected by the least absolute shrinkage and selection operator logistic regression and applied to Cox proportional hazards modeling with clinical predictors. Results Among the 5798 patients, 53 developed PRNN—an incidence rate of 0.89%. Age > 55 years, diabetes, LDH > 170 U/L, and tumor volume of nasopharynx > 60.5 cm3,were independently associated with risk of PRNN(all p 55 years, diabetes mellitus, LDH > 170 U/L, tumor volume of nasopharynx > 60.5 cm3, D0.5cc EQD2 > 80.20 Gy, and V77.0 80.20 Gy and V77.0 80.20 Gy is a reliable evidence-based new complement to dose constraint, especially for T3-4 disease, who received high prescribe dose in China.