[(11)C]Choline uptake with PET/CT for the initial diagnosis of prostate cancer: relation to PSA levels, tumour stage and anti-androgenic therapy.

Purpose The accuracy of positron emission tomography (PET)/CT with [11C]choline for the detection of prostate cancer is not well established. We assessed the dependence of [11C]choline maximum standardized uptake values (SUVmax) in the prostate gland on cell malignancy, prostate-specific antigen (PSA) levels, Gleason score, tumour stage and anti-androgenic hormonal therapy. Methods In this prospective study, PET/CT with [11C]choline was performed in 19 prostate cancer patients who subsequently underwent prostatectomy with histologic sextant analysis (group A) and in six prostate cancer patients before and after anti-androgenic hormonal therapy (bicalutamide 150 mg/day; median treatment of 4 months; group B). Results In group A, based on a sextant analysis with a [11C]choline SUVmax cutoff of 2.5 (as derived from a receiver-operating characteristic analysis), PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 72, 43, 64, 51 and 60%, respectively. In the patient-by-patient analysis, no significant correlation was detected between SUVmax and PSA levels, Gleason score or pathological stage. On the contrary, a significant (P<0.05) negative correlation was detected between SUVmax and anti-androgenic therapy both in univariate (r 2=0.24) and multivariate (r 2=0.48) analyses. Prostate [11C]choline uptake after bicalutamide therapy significantly (P<0.05) decreased compared to baseline (6.4±4.6 and 11.8±5.3, respectively; group B). Conclusion PET/CT with [11C]choline is not suitable for the initial diagnosis and local staging of prostate cancer. PET/CT with [11C]choline could be used to monitor the response to anti-androgenic therapy.