Extension of Local Disease in Nasopharyngeal Carcinoma Detected by Magnetic Resonance Imaging: Improvement of Clinical Target Volume Delineation

In patients presenting with NPC, local disease spreads stepwise from proximal sites to more distal sites. Tumors extend quickly through privileged pathways such as neural foramina. The anatomic sites surrounding the nasopharynx are at low risk of concurrent bilateral tumor invasion. Selective radiotherapy of the local disease in NPC may be feasible.