title: Is primary tumor volume still a prognostic factor in intensity modulated radiation therapy for nasopharyngeal carcinoma?
abstract: OBJECTIVE
  To evaluate the prognostic value of gross primary tumor volume (GTV-P) in nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiotherapy (IMRT).
  
  
  METHODS
  A total of 694 nonmetastatic and histologically proven NPC patients who underwent IMRT were retrospectively reviewed. Samples were split randomly into a training set (n=232) and a test set (n=462) to analysis. The receiver operating characteristic (ROC) curves were calculated to identify the cut-off point and test the prognostic validity of the GTV-P. The correlations between GTV-P and the American Joint Committee on Cancer (AJCC) disease stages were also analyzed.
  
  
  RESULTS
  The 5-year disease-free survival (DFS), overall survival (OS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) rates for NPC patients with GTV-P<19 vs. ≥19 ml were 94.9% vs. 64.8%, 97.0% vs. 76.4%, 98.2% vs. 92.5% and 97.1% vs. 75.2%, respectively (all P<0.05) in all patients. Multivariate analysis indicated GTV-P was an independent prognostic factor. The ROC curve verified that the predictive ability of T classifications was improved when combined with GTV-P (P<0.001).
  
  
  CONCLUSIONS
  GTV-P is an independent prognostic indicator for treatment outcome after IMRT, and significantly improves the prognostic validity of T classifications in NPC.
authors.affiliation: Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Yu
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Yin
authors.forename: Wen-Fei
authors.initials: WF
authors.lastname: Li
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Chen
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.forename: Li-Zhi
authors.initials: LZ
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D002945:Cisplatin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009367:Neoplasm Staging; D011379:Prognosis; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D047368:Tumor Burden
chemical_list: D002945:Cisplatin