18F-FCH (Fluorocholine)-PET/MR in Staging of High-Risk Prostate Cancer

Up to 60% of patients treated with radical prostatectomy or external beam radiotherapy for prostate cancer will have biochemical failure at 5 years. This may be due to several reasons, including presence of sub-clinical metastases at time of local therapy. Currently, patients with high risk prostate cancer are staged by MRI of the prostate (to assess local extent of disease), CT of the abdomen(to detect spread to lymph nodes) and bone scan (to assess for spread to bones). However, these standard imaging exams do not always identify all sites of disease. Recent research has suggested that performing positron emission tomography (PET) scanning with a tracer called fluorocholine (FCH) improves identification of lymph node and bone metastases in prostate cancer, resulting in more accurate diagnosis. The main goal of this study is to find out whether staging high risk prostate cancer patients with FCH PET-CT and MRI of the whole body will improve detection of primary tumors and metastases compared to current standard imaging exams. Improved staging of patients with prostate cancer may impact patient care as it will help to select more appropriate therapy. In this study, participants will undergo either combined PET/MRI or PET-CT and MRI after standard evaluations. The accuracy of each staging approach (standard vs. PET and MRI) will be evaluated. In addition, we will incorporate novel methods for data interpretation by creating imaging maps combining data from PET and MRI (termed "Multiparametric maps"). The goal of this novel approach is to find out whether mapping 2 or more characteristics of a tumor at the same time will improve tumor detection and accuracy of diagnosis. About 40 men from the Princess Margaret Hospital will take part in this study. The study should take about 2 years to complete enrollment and the results should be known within 36 months of completion of enrollment.