Role of 18F-Choline PET/CT in the Initial Staging of High Risk Prostate Cancer and Comparison with Conventional Imaging Techniques

ABSTRACT

Objective: To assess the diagnostic accuracy of 18F-Choline PET/CT in the initial staging of high-risk prostate cancer (PC), and to compare it with conventional imaging techniques and to assess the changes in therapeutic attitude derived from its results. Secondary Objectives: To assess the concordance between 18F-Choline PET/CT and conventional study and to find related prognostic factors. Material and Methods: Retrospective observational study of 78 patients with high-risk PC undergoing 18F-Choline PET/CT after conventional initial staging (CT + BS). Sensitivity, specificity and predictive values of 18F-Choline PET/CT and CT + BS were calculated. The golden standard was histological result or follow-up. Tumor characteristics were collected and univariate and multivariate analyzes were performed. Results: The median age was 67 years old and mean PSA was 42.39 ng/mL. The sensitivity, specificity and NPV in global initial staging for PET/CT 18F-Choline and conventional imaging were 92.9% vs 38.5%, 83.3% vs 42.3%, and 90.9% vs 40.7%, respectively. Lymph node staging sensitivity 96.3% vs 61.5% and specificity 80% vs 76%, respectively. Bone staging sensitivity 91.7% vs 21.4% and specificity 97.4% vs 83.8%, respectively. There was agreement in 25 patients (32%) (p = 0.004), Kappa index 0.134 (p = 0.011). The treatment was modified in 47.4% patients. PSA, PSADT% positive cores and cT were related to PET results. PSA level <8.9 ng/mL was considered an independent protective factor for positive PET (OR 0.03) (95% CI 0.002-0.435, p 0.010). Conclusions: 18F-Choline PET/CT seems to be superior to CT + BS for initial staging in high-risk PC. It could be considered because its results can change the treatment decision in almost half of the patients (AU)