Postradiation nasopharyngeal necrosis (PRNN) frequently develops after second-course radiotherapy for nasopharyngeal carcinoma (NPC). PRNN can lead to internal carotid artery (ICA) massive hemorrhage due to ICA rupture, resulting in sudden death. This study aims to explore the pretreatment of the ICA to prevent fatal massive hemorrhage in PRNN patients.Retrospective cohort study.Sun Yat-sen University Cancer Center.Patients diagnosed with NPC and PRNN from January 2010 to September 2022 were included. The Cox proportional hazards regression analysis was performed to analyze risk factors for massive hemorrhage and survival. A nomogram was developed to integrate prognostic models and perform parameter calibration.Two hundred and fifty-four PRNN patients were included in this study. Prophylactic ICA occlusion significantly reduced the risk of ICA hemorrhage compared to no prophylactic ICA occlusion (3.6% vs 40.6%, P < .001). Surgical repair on necrosis significantly prevented hemorrhage and improved survival. The nomogram, incorporating the above 2 factors and the nearest distance from necrosis to ICA ≤ 3 mm, exhibited excellent discriminative ability for hemorrhage. We identified 3 high-risk factors that indicate the need for prophylactic ICA management in PRNN patients: (1) exposure of ICA by rhinoscopy; (2) signs of ICA erosion on MRA scanning; (3) the depth of soft tissue coverage surrounding the ICA wall within the necrotic cavity is less than 3 mm on magnetic resonance imaging.We have identified 3 high-risk factors for PRNN patients that necessitate prophylactic ICA management. These findings are expected to contribute to improving the quality of life and overall survival of PRNN patients.© 2023 American Academy of Otolaryngology-Head and Neck Surgery Foundation.