Intensity-modulated radiotherapy prolongs the survival of patients with nasopharyngeal carcinoma compared with conventional two-dimensional radiotherapy: A 10-year experience with a large cohort and long follow-up

Background To evaluate the survival benefit of intensity-modulated radiotherapy (IMRT) compared with conventional two-dimensional radiotherapy (2D-CRT) in nasopharyngeal carcinoma (NPC) using a large cohort with long follow-up. Methods We retrospectively analysed 7081 non-metastatic NPC patients who received curative IMRT or 2D-CRT from February 2002 to December 2011. Results Of the 7081 patients, 2245 (31.7%) were administered IMRT, while 4836 (68.3%) were administered 2D-CRT. At 5 years, the patients administered IMRT had significantly higher local relapse-free survival (LRFS), loco-regional relapse-free survival (LRRFS), progression-free survival (PFS) and overall survival (OS) (95.6%, 92.5%, 82.1% and 87.4%, respectively) than those administered 2D-CRT (90.8%, 88.5%, 76.7% and 84.5%, respectively; p < 0.001). The distant metastasis-free survival (DMFS) was higher for IMRT than 2D-CRT, with borderline significance (87.6% and 85.7%, respectively; p = 0.056). However, no difference was observed between IMRT and 2D-CRT in nodal relapse-free survival (NRFS; 96.3% and 97.4%, respectively; p = 0.217). Multivariate analyses showed that IMRT was an independent protective prognostic factor for LRFS, LRRFS and PFS, but not NRFS, DMFS or OS. Conclusions IMRT provided an improved LRFS, LRRFS and PFS in both the early and advanced T classifications and overall stage for non-disseminated NPC compared with 2D-CRT. However, no significant advantage was observed in NRFS, DMFS or OS when IMRT was used.