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PURPOSE: Detection of recurrence in prostate cancer patients with biochemical failure after radical prostatectomy by [(11)C]choline PET/CT depends on the prostate-specific antigen (PSA) level. The role of other clinical and pathological variables has not been explored. METHODS: A total of 2,124 prostate cancer patients referred to our Institution for [(11)C]choline PET/CT from December 2004 to January 2007 for restaging of disease were retrospectively considered for this study. Inclusion criteria were: previous treatment by radical prostatectomy, and biochemical failure, defined as at least two consecutive PSA measurements of >0.2 ng/ml. These criteria were met for 358 patients. Binary logistic analysis was used to investigate the predictive factors of [(11)C]choline PET/CT. PET/CT findings were validated using criteria based on histological analysis, and follow-up clinical and imaging data. Receiver operating characteristic (ROC) analysis was used to assess the performance of [(11)C]choline PET/CT in relation to PSA levels. RESULTS: The mean PSA level was 3.77 +/- 6.94 ng/ml (range 0.23-45 ng/ml; median 1.27 ng/ml). PET/CT was positive for recurrence in 161 of 358 patients (45%). On an anatomical region basis, [(11)C]choline pathological uptake was observed in lymph nodes (107/161 patients, 66%), prostatectomy bed (55/161 patients, 34%), and in the skeleton (46/161 patients, 29%). PET/CT findings were validated using histological criteria (46/358, 13%), and follow-up clinical and imaging criteria (312/358, 87%). Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were, respectively, 85%, 93%, 91%, 87%, and 89%. In multivariate analysis, high PSA levels, advanced pathological stage, previous biochemical failure and older age were significantly (P < 0.05) associated with an increased risk of positive PET/CT findings. The percentage of positive scans was 19% in those with a PSA level between 0.2 and 1 ng/ml, 46% in those with a PSA level between 1 and 3 ng/ml, and 82% in those with a PSA level higher than 3 ng/ml. ROC analysis showed that PET/CT-positive and PET/CT-negative patients could be best distinguished using a PSA cut-off value of 1.4 ng/ml. CONCLUSIONS: In addition to PSA levels, pathological stage, previous biochemical failure and age should be considered by physicians when referring prostate cancer patients with biochemical failure after radical prostatectomy to [(11)C]choline PET/CT.

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

Dear Sir, Anti-androgenic therapy compromises not only the quality of life of many unfortunate men with prostate cancer (PCa), but also makes the lives of diagnosticians uncomfortable. In a recent paper published in the EJNMMI, Giovacchini et al. [1] reported their experience using [C]choline PET/CT for detecting PCa in 12 hormone-naive patients and seven patients with anti-androgenic treatment for PCa. All patients had PCa, known from a pre-imaging biopsy and confirmed by later radical prostatectomy and routine sextant histopathological analysis, which was used as gold standard for imaging results. The authors present a detailed report of the results of histopathological sextant analysis and sextant SUVmax of [ C]choline above a threshold of 2.5, used as a surrogate marker for malignancy (Table 2 of ref. [1]). From these data, it is immediately clear that, in all hormone-naive patients, at least two sextants with histopathologically demonstrated PCa were correctly identified by SUVmax of [C]choline, resulting in a sensitivity of 100% for detecting PCa on a patient basis in this patient sample of 12 subjects. Seven patients under anti-androgenic treatment had virtually identical serum PSA concentrations (10.3±7.9 vs 12.9± 8.4 ng/ml, p=0.7) and lower SUVmax of [ C]choline (3.1± 1.0 vs 5.4±1.7, p 10 mm movement between PET and CT depending on bladder and bowl distension and a sampling error due to different slice thickness of histopathology (10 μm) and PET (4–5 mm), rendering comparative evaluation of histopathology and imaging very difficult. Nevertheless, complete demonstration of all intra-prostatic multi-focal manifestations of PCa by any non-invasive imaging modality is one of the hot unresolved issues in diagnostic oncologic imaging, whereas as shown in Table 2 of ref. [1], two of six sextants afflicted by PCa could be demonstrated with [C]choline PET/CT in hormone-naive patients similar to the results reported by other authors [3–5]. T-staging of PCa involves the assessment of capsular penetration, seminal vesical infiltration and/or infiltration of neurovascular bundles, structures which can only be reliably imaged with MRI, thus needing the latter imaging approach [6] for staging purposes. Finally, we find it difficult to draw any conclusions on clinical management based on 12 evaluable patients: this Eur J Nucl Med Mol Imaging (2008) 35:1740–1741 DOI 10.1007/s00259-008-0839-5