Positron emission tomography with ¹¹C-acetate and ¹⁸F-FDG in prostate cancer patients

Visualisation of primary prostate cancer, its relapse and its metastases is a clinically relevant problem despite the availability of state-of-the-art methods such as CT, MRI, transrectal ultrasound and fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET). The aim of this study was to evaluate the efficacy of carbon-11 acetate and ¹⁸F-FDG PET in the detection of prostate cancer and its metastases. Twenty-five patients were investigated during the follow-up of primary prostate cancer, suspected relapse or metastatic disease using ¹¹C-acetate PET; 15 of these patients were additionally investigated using ¹⁸F-FDG PET. Fourteen patients were receiving anti-androgen treatment at the time of the investigation. Lesions were detected in 20/24 (83%) patients using ¹¹C-acetate PET and in 10/15 (75%) patients using ¹⁸F-FDG PET. Based on the results of both PET scans, one patient was diagnosed with recurrent lung cancer. Median ¹⁸F-FDG uptake exceeded that of ¹¹C-acetate in distant metastases (SUV =3.2 vs 2.3). However, in local recurrence and in regional lymph node metastases, ¹¹C-acetate uptake (median SUVs =2.9 and 3.8, respectively) was higher than that of ¹⁸F-FDG (median SUVs =1.0 and 1.1, respectively). A positive correlation was observed between serum PSA level and both ¹¹C-acetate uptake and ¹⁸F-FDG uptake. ¹¹C-acetate seems more useful than ¹⁸F-FDG in the detection of local recurrences and regional lymph node metastases. ¹⁸F-FDG, however, appears to be more accurate in visualising distant metastases. There may be a role for combined ¹¹C-acetate/¹⁸F-FDG PET in the follow-up of patients with prostate cancer and persisting or increasing PSA.