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

Abstract

Background: Conventional imaging (CI) techniques are inadequate for lymph node (LN) staging in prostate cancer (PCa). Objectives: To 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 Participants: From 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. Measurements: Sensitivity, 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 Limitations: Fifteen 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). Conclusions: In 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. © 2008 European Association of Urology.