Utility of F-18 fluorodeoxyglucose posıtron emıssıon tomography/computed ın carcınoma of unknown primary

Int J Clin Exp Pathol. 2014 Dec 1;7(12):8941-6. eCollection 2014.

Abstract

Carcinoma of unknown primary (CUP) is a heterogeneous group of tumors with various clinical features causing diagnostic and therapeutic challenges. The aim of this study was to evaluate the ability of F-18 FDG PET/CT for localizing the primary tumor, disclosing additional metastases, and changing the treatment in patients with CUP. One hundred and twelve metastatic patients (female = 40, male = 72, median age = 60.5 years) in whom conventional diagnostic work-up failed to disclose the primary tumor were included in the study. F-18 FDG PET/CT imaging was performed in a standard protocol (patient supine, arms on patient's side, vertex to thigh, 369.3 MBq (296-444 MBq) F-18 FDG, a 60-minute uptake period, 6-7 bed position). Histopathology was taken as the only reference standard. F-18 FDG PET/CT correctly detected primary tumor in 37 of 112 (33.03%) patients. The most common site of primary tumor detected by F-18 FDG PET/CT was lung (n = 18), which was followed by nasopharynx (n = 7), pancreas (n = 5), tonsil (n = 2), breast (n = 2), thyroid (n = 1), uterus (n = 1) and colon/rectum (n = 1). F-18 FDG PET/CT imaging disclosed additional previously undetected metastases in 32 (28.5%) and changed the treatment in 33 (29.4%) of 112 patients. There were false positive F-18 FDG PET/CT results in 21 (18.5%) patients. F-18 FDG PET/CT is able to disclose the primary tumor, disclose new metatases and change the treatment in about one third of patients with CUP.

Keywords: Carcinoma of unknown primary; F-18 FDG PET/CT; metastases; treatment change.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Male
  • Middle Aged
  • Multimodal Imaging / methods*
  • Neoplasms, Unknown Primary / diagnostic imaging*
  • Positron-Emission Tomography / methods
  • Radioisotopes*
  • Tomography, X-Ray Computed / methods
  • Young Adult

Substances

  • Radioisotopes
  • Fluorodeoxyglucose F18