title: Differential roles of 18F-FDG PET in patients with locoregional advanced nasopharyngeal carcinoma after primary curative therapy: response evaluation and impact on management.
abstract: This prospective study compares the efficacies of whole-body (18)F-FDG PET and a conventional work-up (CWU) in evaluating the treatment response for patients with locoregional advanced nasopharyngeal carcinoma (NPC) after primary curative therapy and investigates the impact of PET on patient management.
  
  
  METHODS
  Patients who had locoregional advanced NPC (stages III and IVa-b, staged by (18)F-FDG PET and CWU) and who had completed primary curative therapy for 3 mo were enrolled. The curative therapy consisted of concurrent chemoradiotherapy with or without induction chemotherapy. All of the patients also underwent (18)F-FDG PET and CWU to evaluate the response. The criteria for final diagnosis were based on pathology or subsequent follow-up for at least 6 mo. Rates of detection by (18)F-FDG PET and CWU and the impact on management were determined on site and patient bases, respectively.
  
  
  RESULTS
  From January 2002 to August 2005, 131 patients with NPC were eligible, including 71 patients with stage III NPC (group A) and 60 patients with stage IVa-b NPC (group B). Twelve patients were proven to have residual tumors. (18)F-FDG PET had a higher overall sensitivity than CWU in group A (100% vs. 25%) and group B (91.7% vs. 58.3%). The overall specificity of PET was significantly higher than that of CWU in group B (97.6% vs. 91.7%; P = 0.019) but was slightly lower in group A (95.7% vs. 96.7%). The overall accuracy of PET also was significantly higher than that of CWU in group B (97.2% vs. 89.4%; P = 0.002) but was similar to that of CWU in group A (95.8% vs. 95.3%). PET resulted in management changes in 11 patients (15.4%; 11/71) in group A, with positive and negative impacts on 3 and 8 patients, respectively. In group B, the management of 26 of 60 patients (43%) was changed as a result of PET and included positive impacts on 23 patients and negative impacts on 3 patients.
  
  
  CONCLUSIONS
  (18)F-FDG PET plays differential roles in patients with stage III NPC and stage IVa-b NPC after primary curative therapy. PET has higher sensitivity and specificity in evaluating the response and results in better management of patients with stage IVa-b NPC. PET has a less prominent impact on patient management but higher sensitivity in patients with stage III NPC.
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Chan
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Kang-Hsing
authors.initials: KH
authors.lastname: Fan
authors.forename: Joseph Tung-Chieh
authors.initials: JT
authors.lastname: Chang
mesh_terms: D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18