title: [The clinical significance of poststyloid space extension in nasopharyngeal carcinoma].
abstract: OBJECTIVE
  To explore the clinical significance of poststyloid space extension in nasopharyngeal carcinoma.
  
  
  METHODS
  One hundred and ninety-eight patients with newly treated nasopharyngeal carcinoma (stage I-IV a) were analyzed. These patients were divided into two groups depending on whether the poststyloid space was extended or normal. The 5-year survival rate, relapse and distant metastasis after the treatment were estimated using the Kaplan-Meier, Log-Rank methods.
  
  
  RESULTS
  The rates of patients with oropharyngeal extension for these two groups were 72.1% and 16.8% respectively (P < 0.001). The rates of the cases with involvement of the 9, 10, 11, 12th cranial nerves were 20.9% and 6.2% respectively (P < 0.01). The rates of metastasis to cervical lymph node were 69.8% and 35.4% respectively (P < 0.01). The 5-year survival rates were 46.76% and 68.88% respectively (P = 0.0027). The local control rates were 63.7%, 78.7% respectively (P = 0.0862). The distant metastasis free survival rates were 71.7% and 84.2% respectively (P = 0.0468). These results showed that the survival rate, the local control rate were reduced and the distant metastasis was increased for patients with poststyloid space extension.
  
  
  CONCLUSIONS
  The poststyloid space extension was an important prognostic factor with poorer treatment outcome. It is reasonable to classify such condition as stage T3 of nasopharyngeal carcinoma.
authors.affiliation: Department of Radiotherapy, Cancer Center, Sun Yet-sen University of Medical Science, Guangzhou 510060, China.
authors.forename: C
authors.initials: C
authors.lastname: Zhao
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Zeng
authors.forename: T
authors.initials: T
authors.lastname: Lu
authors.forename: N
authors.initials: N
authors.lastname: Cui
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009959:Oropharyngeal Neoplasms / Q000473:pathology*; D011379:Prognosis