title: Comparison of the treatment outcomes of intensity-modulated radiotherapy and two-dimensional conventional radiotherapy in nasopharyngeal carcinoma patients with parapharyngeal space extension.
abstract: OBJECTIVE
  This study investigated the contribution of intensity-modulated radiotherapy (IMRT) to improved treatment outcome in patients with nasopharyngeal carcinoma (NPC) and parapharyngeal space (PPS) extension.
  
  
  METHODS
  A total of 1052 cases with PPS extension were retrospectively reviewed, including 512 (48.7%) patients treated with two-dimensional conventional radiotherapy (2D-CRT) and 540 (51.3%) patients treated with IMRT.
  
  
  RESULTS
  Significant differences in local relapse-free survival (LRFS) and overall survival (OS) (P<0.001, P<0.001, respectively), but not distant metastasis-free survival (DMFS; P=0.383), were observed between the 2D-CRT and IMRT groups in univariate analysis. The radiotherapy technique was found to be an independent prognostic factor for death (HR=0.674, 95% CI: 0.537-0.846, P=0.001) and local recurrence (HR=0.486, 95% CI: 0.324-0.727, P<0.001), but not for DMFS. IMRT improved local control in patients with carotid space (CS) involvement compared to 2D-CRT (P<0.001). LRFS was significantly different between patients with and without CS extension in the 2D-CRT group (P<0.001), but not in the IMRT group (P=0.215).
  
  
  CONCLUSIONS
  Compared to 2D-CRT, IMRT improved LRFS in patients with PPS extension, especially patients with CS extension, but did not improve DMFS. CS extension was not statistically prognostic for local control in NPC patients with PPS extension.
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Ling-Long
authors: LL
authors: Tang
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Lei
authors: L
authors: Chen
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Yan-Ping
authors: YP
authors: Mao
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Wen-Fei
authors: WF
authors: Li
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Ying
authors: Y
authors: Sun
authors: Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Li-Zhi
authors: LZ
authors: Liu
authors: Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors: Ai-Hua
authors: AH
authors: Lin
authors: Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Hai-Qiang
authors: HQ
authors: Mai
authors: Department of Molecular Diagnostics, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Jian-Yong
authors: JY
authors: Shao
authors: Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China.
authors: Li
authors: L
authors: Li
authors: Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. Electronic address: majun2@mail.sysu.edu.cn.
authors: Jun
authors: J
authors: Ma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000517:prevention & control; D010614:Pharynx; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods* / Q000401:mortality; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Intensity-modulated radiotherapy; Magnetic resonance imaging; Nasopharyngeal carcinoma; Parapharyngeal space; Prognosis