Outcomes and prognostic factors of conformal radiotherapy versus intensity-modulated radiotherapy for nasopharyngeal carcinoma

This study retrospectively compared outcomes and prognostic factors of nasopharyngeal carcinoma (NPC) treated with conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT). The treatment records of 182 patients treated with IMRT and 198 patients treated with CRT from April 2005 to December 2007 in our hospital were reviewed. The clinical characteristics, treatment outcomes (including survival analysis and acute and late toxicity), and prognostic factors of the two groups were compared. The 4-year local-regional control (LRC), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) of the IMRT and CRT groups were 93.6 and 85.3 %, 79.1 and 73.6 %, 74.7 and 65.0 %, and 83.5 and 72.1 %, respectively. The acute radiation dermatitis and xerostomia of the two groups were significantly different (P < 0.05). In the IMRT group, OS between different T stages could not be well separated. Multivariate analysis revealed that, in the CRT group, the clinical stage and T and N stages were significant prognostic factors for OS, DMFS, and DFS and that T stage was a significant prognostic factor for LRC. In the IMRT group, T and N stages had no predictive value for outcomes. Compared with CRT, IMRT has a better prognosis and less adverse effects. For IMRT, T stage was not a significant prognostic factor for LRC, DMFS, DFS, or OS. An effective treatment strategy is needed for distant control. With the increasing use of IMRT and continued modulation of treatment strategies for NPC, the current staging system faces great challenges.