Feedback on Baseline Use of Staging Images is Important to Improve Image Overuse with Newly Diagnosed Prostate Cancer Patients

Background: The objective of this study was to evaluate baseline use and positive rates of staging images (bone scan, CT) in newly diagnosed patients with prostate cancer (PCa) and to improve staging image overuse. Materials and Methods: This retrospective study covered a consecutive series of patients with PCa who underwent stage imaging at our institution between 2006 and 2011. Various clinical and pathological variables (age, PSA, biopsy Gleason score, clinical T stage, positive biopsy core rate) were evaluated by multivariate logistic regression analysis for their ability to predict a positive staging image. All patients were stratified according to the NCCN risk stratification and positive rates were compared in each risk group. Results: 410 patients (100%) underwent a bone scan and 315 patients (76.8%) underwent a CT scan. Some 51 patients (12.4%) had a positive bone scan, clinical T3 and T4 being significant independent predictors. Positive bone scan rates for low-, intermediate-, high-, and very high-risk groups were 0%, 0%, 8.25%, and 56.6%. Some 59 (18.7%) patients had a positive CT scan, with elevated PSA and clinical T3, T4 as significant independent predictors. Low-, intermediate-, high- and very high-risk group rates were 0%, 0%, 13.8% and 80.0%. Conclusions: The incidences of positive staging image in low- and intermediate- risk group were reasonably low. Following feedback on these results, staging in low- and intermediate- risk groups could be omitted.