Diagnostic role of fluorodeoxyglucose positron emission tomography-computed tomography in prostate cancer

The role of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) in prostate cancer remains controversial due to a limited number of previous clinical investigations. The aim of the present retrospective study was to assess the diagnostic value of FDG PET-CT in prostate cancer, with an emphasis on the detection of metastatic disease. Twenty-five relevant cases of patients with newly diagnosed prostate cancer, referred for staging, or with a history of prostate cancer or recent prostate specific antigen (PSA) relapse, referred for the detection of metastatic disease, were included in the present study. None of the patients had known imaging or pathological evidence of metastatic disease prior to FDG PET-CT, however, the PSA levels had been recorded in all patients in the two months prior to FDG PET-CT imaging. Verification of the FDG PET-CT observations was made by biopsy, regional diagnostic CT and/or whole-body bone scintigraphy. The sensitivity of FDG PET-CT in identifying untreated primary lesions was only 33% (3/9). However, FDG PET-CT detected metastatic disease in six of the nine patients who underwent initial staging. Out of 16 patients with previous treatments and recent PSA relapse, FDG PET-CT successfully identified metastatic diseases in 12 and tumor recurrence within the prostatic fossa of two patients. The difference in the PSA levels was identified to be statistically significant between the FDG PET-CT-positive and -negative subgroups of the 16 restaging patients. The results indicated that FDG PET-CT is not useful for the diagnosis of prostate cancer, but may aid with the detection of metastatic disease in appropriately selected patients.