Abstract：Objective: To evaluate the role of whole body PET/CT scan with (18)F-fluorodeoxyglucose(FDG) in the detection of the primary tumor in patients with metastatic cancer from unknown primary origin. Methods: Fifty-four consecutive patients, with biopsy proven tumor metastases from unknown primary site, underwent a whole-body FDG-PET/CT study. Results: The primary tumor site was correctly identified by FDG-PET/CT in 41 patients(41/54, 75.9%). In 13 patients(13/54, 24.1%), the primary tumor site was not localized. However, in 35 cases(35/54, 64.8%) of them, FDG-PET/CT scan identified further unexpected metastases, modifying the stage of disease. Conclusion: Our data strongly support that the whole body FDG-PET/CT is a useful tool in the evaluation of patients with cancer with unknown primary site and PET/CT is able to find more metastatic lesions.
2008, Vol. 19 
