[(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 [(11)C]choline for the detection of prostate cancer is not well established. We assessed the dependence of [(11)C]choline maximum standardized uptake values (SUV(max)) 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 [(11)C]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 [(11)C]choline SUV(max) 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 SUV(max) and PSA levels, Gleason score or pathological stage. On the contrary, a significant (P < 0.05) negative correlation was detected between SUV(max) and anti-androgenic therapy both in univariate (r (2) = 0.24) and multivariate (r (2) = 0.48) analyses. Prostate [(11)C]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 [(11)C]choline is not suitable for the initial diagnosis and local staging of prostate cancer. PET/CT with [(11)C]choline could be used to monitor the response to anti-androgenic therapy.