title: Impact of FDG-PET/CT for the Detection of Unknown Primary Tumours in Patients with Cervical Lymph Node Metastases.
abstract: OBJECTIVE
  Because the detection of the primary tumour is of importance to optimize the patient's management and allows a targeted therapy, the performance of hybrid positron emission tomography-computed tomography (PET/CT) using fluorodeoxyglucose (FDG) in the detection of primary tumors and unrecognized metastases with cervical lymph node metastases were evaluated in a retrospective study.
  
  
  METHODS
  Twenty patients with cervical lymph node metastases of unknown primary tumors underwent staging with FDG-PET/CT. All underwent head and neck examinations, computed tomography (CT), and/or magnetic resonance imaging (MRI), panendoscopies, and biopsies of head and neck mucosal sites. The diagnostic accuracy of FDG-PET/CT in detecting primary tumors was compared with that of histopathology and clinical follow-up. The ability of FDG-PET/CT to detect distant metastases was also tested.
  
  
  RESULTS
  PET/CT was positive with an increased FDG uptake suggesting the potential primary site in 45% of patients (9/20). PET/CT findings were true positive in 7, true negative in 10, false positive in 2, and false negative in 1 patients, resulting in a sensitivity of 87%, a specificity of 83%, an accuracy of 85%, a positive predictive value of 77% and a negative predictive value of 90%. Also, PET/CT showed distant metastases in seven patients.
  
  
  CONCLUSIONS
  FDG-PET/CT can be successfully used for the identification of the primary site and distant metastases in patients with cervical lymph node metastases from an unknown primary cancer.
  
  
  BACKGROUND
  None declared.
authors.affiliation: Şifa University School Medicine, Deparment of Nuclear Medicine, İzmir, Turkey.
authors.forename: Inanç
authors.initials: I
authors.lastname: Karapolat
authors.forename: Kamil
authors.initials: K
authors.lastname: Kumanlıoğlu
keywords: Fluorodeoxyglucose F18; Neoplasms; head and neck neoplasms; lymphatic metastasis; neoplasm metastasis; positron-emission tomography/computed tomography; unknown primary