11C-Choline Positron Emission Tomography/Computerized Tomography for Preoperative Lymph-Node Staging in Intermediate-Risk and High-Risk Prostate Cancer: Comparison with Clinical Staging Nomograms

BackgroundConventional imaging (CI) techniques are inadequate for lymph node (LN) staging in prostate cancer (PCa).ObjectivesTo assess the accuracy of 11C-Choline positron emission tomography/computerized tomography (PET/CT) for LN staging in intermediate-risk and high-risk PCa and to compare it with two currently used nomograms.Design, Setting, and ParticipantsFrom January 2007 to September 2007, 57 PCa patients at intermediate risk (n = 27) or high risk (n = 30) were enrolled at two academic centres. All patients underwent preoperative PET/CT and radical prostatectomy with extended pelvic LN dissection (PLND). Risk of LN metastasis (LNM) was assessed using available nomograms.MeasurementsSensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and number of correctly recognized cases for LNM detection at PET/CT were assessed. The accuracy of PET/CT for LNM detection was compared with the accuracy of nomograms for LNM prediction by using receiver operating characteristic (ROC) analysis.Results and LimitationsFifteen patients (26%) had LNMs, and a total of 41 LNMs were identified. On a patient analysis, sensitivity, specificity, PPV, NPV, and number of correctly recognized cases at PET/CT were 60.0%, 97.6%, 90.0%, 87.2%, and 87.7% while, on node analysis, these numbers were 41.4%, 99.8%, 94.4%, 97.2%, and 97.1%. The mean diameter (in mm) of the metastatic deposit of true-positive LNs was significantly higher than that of false-negative LNs (9.2 vs 4.2; p = 0.001). PET/CT showed higher specificity and accuracy than the nomograms; however, in pairwise comparison, the areas under the curve (AUCs) were not statistically different (all p values >0.05).ConclusionsIn patients with intermediate-risk and high-risk PCa, 11C-Choline PET/CT has quite a low sensitivity for LNM detection but performed better than clinical nomograms, with equal sensitivity and better specificity.