The Failure Patterns of Nasopharygeal Carcinoma After Intensity-Modulated Radiotherapy and Implications for Surveillance.

High rate of local-regional control can be achieved for patients with NPC after IMRT, while distant metastasis remains as the major cause of failures. Patients with advanced N classification has high risk to develop distant metastasis, and most occurred within 5 years. Developing rational and individualized surveillance strategies based on the high risk factors of recurrence is helpful to balance the survival benefit and medical cost.