title: Nasopharyngeal carcinoma patients with retropharyngeal lymph node metastases: a minimum axial diameter of 6 mm is a more accurate prognostic predictor than 5 mm.
abstract: OBJECTIVE
  The criteria for the diagnosis of metastatic retropharyngeal lymph nodes (RLNs) have not yet been resolved and are not included in the current edition of the American Joint Committee on Cancer (AJCC) staging system (seventh edition) for the staging of nasopharyngeal carcinoma (NPC). The aim of this study was to use MRI to identify an RLN size criterion that can accurately predict prognosis in patients with NPC.
  
  
  METHODS
  Eight hundred seventeen patients with newly diagnosed localized NPC were identified. All of the patients underwent MRI before treatment with definitive radiation therapy. All the MRI studies and medical records were reviewed retrospectively. Overall survival (OS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS) were assessed using SPSS software (version 17.0).
  
  
  RESULTS
  RLN size cutoffs of ≥ 5 mm and of ≥ 6 mm were used. There was no significant difference in OS (p = 0.216), DMFS (p = 0.081), or LRFS (p = 0.067) in patients with RLNs ≥ 5 mm and in those with RLNs < 5 mm. When 6 mm was used as a size cutoff, significant differences in OS (p = 0.000) and DMFS (p = 0.001) were identified; there was no significant difference observed for LRFS (p = 0.380).
  
  
  CONCLUSIONS
  A minimum axial RLN diameter of 6 mm was a more accurate prognostic predictor in NPC patients with RLN metastases than 5 mm.
authors.affiliation: 1 Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Rd East, Guangzhou, Guangdong 510060, People's Republic of China.
authors.forename: Yi-Zhuo
authors.initials: YZ
authors.lastname: Li
authors.forename: Chuan-Miao
authors.initials: CM
authors.lastname: Xie
authors.forename: Yao-Pan
authors.initials: YP
authors.lastname: Wu
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Cui
authors.forename: Zi-Lin
authors.initials: ZL
authors.lastname: Huang
authors.forename: Ci-Yong
authors.initials: CY
authors.lastname: Lu
authors.forename: Pei-Hong
authors.initials: PH
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D002681:China / Q000453:epidemiology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000532:radiotherapy; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control; D009367:Neoplasm Staging; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015996:Survival Rate; D055815:Young Adult
keywords: MRI; nasopharyngeal carcinoma; prognostic value; retropharyngeal lymph node; tumor staging