Investigations with FDG-PET scanning in prostate cancer show limited value for clinical practice

The aim of this study was to investigate FDG-PET (fluorodeoxyglucose positron emission tomography) imaging in the management of prostate cancer. Twenty-two patients were studied during different disease phases of prostate cancer, for staging or restaging to clarify specific clinical questions. FDG-PET was performed encompassing the thorax, abdomen and pelvis using the Penn PET 300H scanner. Scanning was begun 60 min after F-18 fluorodeoxyglucose marker. Patients were catheterized and administered diuretics to minimize urinary activity. Information obtained with FDG-PET was concordant with findings from other investigations in 7/22 (32%) patients, discordant in 15/22 (68%) patients and equivalent in one patient (4%). PET indicated progressive disease in five patients with prostate-specific antigen (PSA) <4 ng/L. The impact on management of the patients was high in 46% of cases, low in 41% and for 14% there was no impact on management. The accuracy of FDG-PET was 72% (95% CI 50-89) as confirmed by invasive diagnostics: follow-up. FDG-PET can provide useful information and improve the clinician's decision on further management procedures in selected patients with low PSA and bone or lymph node changes. A negative PET scan in prostate cancer should be interpreted with caution.