Table 1.

Inclusion and exclusion criteria for patient enrollment.

Inclusion criteria

Exclusion criteria

* Pathologically confirmed non-keratinizing undifferentiated or differentiated NPC * Late T-stage NPC (T3-4N0-3M0, staged or restaged according to the AJCC 8th staging system) * Patients who received induction chemotherapy followed by definitive concurrent chemoradiotherapy * The radiotherapy modality was VMAT or tomotherapy * The radiotherapy plan was available for review * Patients who received treatment at our hospital from November 2016 to December 2020

* Early T-stage or metastatic NPC (T1-2N0-3M0 or T1-4N0-3M1, staged or restaged according to the AJCC 8th staging system) * Patients who did not receive induction chemotherapy * Patients who received palliative radiotherapy * The radiotherapy modality was not VMAT or tomotherapy * The radiotherapy plan was not available for review * Patients who received treatment before November 2016

VMAT, volumetric modulated arc therapy.