title: Prognostic implications of post-therapy (18)F-FDG PET in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.
abstract: OBJECTIVE
  Reliable prognostic factors that serve as a guide to follow-up of patients with locoregionally advanced nasopharyngeal carcinoma (NPC) have not yet been identified. We sought to investigate the prognostic implications of post-therapy PET in patients with NPC treated with chemoradiotherapy.
  
  
  METHODS
  Patients with locoregionally advanced NPC (stages III and IVa-b) who had completed primary curative treatment for 3 months were eligible. All of the patients underwent (18)F-FDG PET and conventional work-up (CWU) for the assessment of treatment response.
  
  
  RESULTS
  A total of 165 patients were enrolled. Over a median follow-up of 58 months, 30 patients died and 41 had disease recurrence. The results of the 3-month post-therapy PET and total lesion glycolysis (TLG) of the primary tumor were independent predictors of overall survival. TNM tumor stage, TLG, and post-therapy PET findings were independently associated with disease-free survival (DFS). The results of post-therapy PET were more predictive of DFS than TNM tumor stage (P < 0.001 vs. P = 0.005). Among patients with stage IVa-b disease, there was a trend toward better 5-DFS rates in patients with a complete metabolic response (CMR) on PET than in those who showed a complete response in the CWU (5-year DFS = 70.7 vs. 63.1 %). Notably, the 1- and 2-year DFS rates were significantly better in the former group compared with the latter. In contrast, the results of post-therapy CWU were not a reliable predictor for DFS.
  
  
  CONCLUSIONS
  The results of post-therapy PET are an important independent prognostic factor in locoregionally advanced NPC. CMR on PET is associated with better DFS rates and could serve as a guidance to individualize the surveillance protocols for patients with stage IVa-b disease.
authors.affiliation: Department of Nuclear Medicine, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan, Will0911@adm.cgmh.org.tw.
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Chan
authors.forename: Wen-Han
authors.initials: WH
authors.lastname: Kuo
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Joseph Tung-Chieh
authors.initials: JT
authors.lastname: Chang
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Cheng-Lung
authors.initials: CL
authors.lastname: Hsu
authors.forename: Kai-Ping
authors.initials: KP
authors.lastname: Chang
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Yu-Jr
authors.initials: YJ
authors.lastname: Lin
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
mesh_terms: D059248:Chemoradiotherapy; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D017211:Treatment Failure
chemical_list: D019788:Fluorodeoxyglucose F18