The role of FDG PET in the diagnosis of occult primary with cervical lymph node metastases: A meta-analysis study

BackgroundDetection of the primary tumor has a key role in the management of patients with unknown primary tumors (UPT).PurposeThe aim of this study is to assess the efficacy of 18F-FDG PET in locating occult primary lesions in patients with metastatic cervical lymphadenopathy.MethodsA systematic search was performed by the PubMed/MEDLINE to identify and select the relevant studies published within the last 20 years (up to 25/08/2011). Reported detection rates, sensitivities and specificities were metaanalyzed. Subgroup analyses were performed if results of individual studies were heterogeneous.ResultsThirty studies met the inclusion criteria. The overall sensitivity, specificity and accuracy rates of FDG-PET in detecting unknown primary tumors were 80.6%, 82.1% and 81.5% respectively.Furthermore, FDG-PET detected 33.5% of tumors that were not apparent after conventional workup. Whereas PET/CT scans’ overall sensitivity, specificity and accuracy were 82.5%, 80.2% and 81.4% respectively. Furthermore, PET/CT detected 30.7% of tumors that were not apparent after conventional workup. There were no significant differences between the diagnostic accuracies of FDGPET and PET/CT scans.Conclusions18F-FDG PET could be useful in patients with UPT for the detection of the primary tumor. 18F-FDG PET has high sensitivity, indicating the existence of few false-negative results, an important feature in the management of oncologic patients that could suggest its utility in the initial stages of the management process.