title: The value of 18F-FLT PET for detecting second primary cancers and distant metastases in head and neck cancer patients.
abstract: OBJECTIVE
  Diagnostic efficacy of (18)F-FLT PET was compared with that of (18)F-FDG PET regarding second primary cancers and distant metastases of head and neck squamous cell cancers (HNSCCs).
  
  
  METHODS
  A total of 88 patients with HNSCCs were qualitatively examined with FLT PET and FDG PET for regions of focally increased metabolism. Final diagnoses of second primary cancer and distant metastasis were established on the basis of histological findings or clinical follow-up.
  
  
  RESULTS
  FDG PET had 1 false-negative finding with lung metastasis, and FLT PET had 4 false-negative findings with 1 liver metastasis, 1 bone metastasis, and 2 lung metastases. There were no false-positive findings with FLT PET in contrast to 9 with FDG PET (1 in lung, 4 in mediastinum, 1 in rectum, and 3 in stomach). Overall accuracy of FDG PET and FLT PET for pretreatment metastasis staging was 92% and 98%, respectively. Five distant metastases in 3 patients occurred after the initiation of chemoradiotherapy. FLT PET missed 2 metastatic lesions (1 in liver and 1 in lung), whereas FDG PET could not discriminate intracranial metastasis because of FDG uptake in the brain.
  
  
  CONCLUSIONS
  FLT PET does not appear to be recommendable to replace FDG PET for pretreatment metastasis staging in HNSCC cases because of its lower sensitivity and higher background activity in the liver and bone marrow. However, it might provide additional diagnostic specificity and biological information.
authors: Department of Otolaryngology, Faculty of Medicine, Kagawa University, Kagawa, Japan. hiro@kms.ac.jp
authors: Hiroshi
authors: H
authors: Hoshikawa
authors: Takehito
authors: T
authors: Kishino
authors: Terushige
authors: T
authors: Mori
authors: Yoshihiro
authors: Y
authors: Nishiyama
authors: Yuka
authors: Y
authors: Yamamoto
authors: Nozomu
authors: N
authors: Mori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015224:Dideoxynucleosides; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D012680:Sensitivity and Specificity
chemical_list: D015224:Dideoxynucleosides; C002854:alovudine