Radiation-Induced Rhinosinusitis After Treatment of Nasopharyngeal and Selected Sinonasal Cancers: A Narrative Review

Radiotherapy is central to the treatment of nasopharyngeal carcinoma and selected sinonasal malignancies, but sinonasal toxicity remains incompletely characterized. Radiation-induced rhinosinusitis (RIR) is increasingly recognized after head-and-neck radiotherapy, particularly in nasopharyngeal carcinoma, where the paranasal sinuses and drainage pathways may receive substantial incidental dose. Reported prevalence varies widely because studies use different endpoints, including radiologic mucosal thickening, endoscopic inflammation, and patient-reported symptoms. Across available nasopharyngeal carcinoma cohorts, imaging-defined sinonasal inflammatory changes are common, with reported rates generally ranging from approximately 30% to more than 70% depending on timing, radiation technique, and diagnostic criteria. This narrative review summarizes current evidence on the epidemiology, pathophysiology, dosimetric predictors, imaging findings, prevention, and management of RIR. Radiation-induced sinonasal injury appears to arise from epithelial damage, impaired mucociliary clearance, altered local defense, and chronic mucosal remodeling. Available data suggest that higher doses to the paranasal sinuses and drainage pathways, baseline sinus disease, and tumor extension into sinonasal structures increase risk, although validated dose constraints are not yet established. We propose a harmonized reporting framework that integrates symptoms, endoscopy, imaging, dosimetry, baseline sinonasal status, and oncologic context. Greater recognition of RIR as a clinically meaningful survivorship toxicity may support more consistent outcome reporting, prospective studies, and future radiation-planning strategies aimed at reducing sinonasal morbidity.