title: Prognostic value of parapharyngeal extension in nasopharyngeal carcinoma treated with intensity modulated radiotherapy.
abstract: OBJECTIVE
  The development of improved diagnostic and therapeutic techniques has revolutionized the management of nasopharyngeal carcinoma (NPC). The purpose of this study is to revaluate the prognostic value of parapharyngeal extension in NPC in the IMRT era.
  
  
  METHODS
  We retrospectively reviewed data from 749 biopsy-proven non-metastatic NPC patients. All patients were examined with magnetic resonance imaging (MRI) and received intensity-modulated radiotherapy (IMRT) as the primary treatment.
  
  
  RESULTS
  The incidence of parapharyngeal extension was 72.1%. A significant difference was observed in the disease-free survival (DFS; 70.3% vs. 89.1%, P<0.001), distant metastasis-free survival (DMFS; 79.3% vs. 92.0%, P<0.001), and local relapse-free survival (LRFS; 92.8% vs. 99.0%, P=0.002) of patients with and without parapharyngeal extension. Parapharyngeal extension was an independent prognostic factor for DFS and DMFS in multivariate analysis (P=0.001 and P=0.015, respectively), but not LRFS. The difference between DMFS in patients with or without parapharyngeal space extension was statistically significant in patients with cervical lymph node metastasis (P<0.001).
  
  
  CONCLUSIONS
  In the IMRT era, parapharyngeal extension remains a poor prognosticator for DMFS in NPC, especially in patients with positive lymph node metastasis. Additional therapeutic improvements are required to achieve a favorable distant control in NPC with parapharyngeal extension.
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Ling-Long
authors.initials: LL
authors.lastname: Tang
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Wen-Fei
authors.initials: WF
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Li-Zhi
authors.initials: LZ
authors.lastname: Liu
authors.affiliation: Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
authors.affiliation: Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China. Electronic address: majun@sysucc.org.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009361:Neoplasm Invasiveness; D010614:Pharynx / Q000473:pathology*; D011379:Prognosis; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies
keywords: Intensity-modulated radiotherapy; Magnetic resonance imaging; Nasopharyngeal carcinoma; Parapharyngeal extension; Prognostic value