Magnetic Resonance Imaging to Locate and Characterize Prostate Cancer

Accurate spatial delineation and biologic characterization of tumors within the prostate gland by non-invasive means, such as MR imaging, stands to impact the spectrum of prostate cancer care. At present there are no imaging techniques that can accurately delineate tumor extent. With dynamic contrast enhanced MRI (DCE-MRI), signal intensity can be plotted over time for various regions of interest within the prostate, and reflect physiological parameters such as tissue perfusion, blood flow, vascular density and vascular permeability. Preliminary studies suggest that malignant tumors demonstrate a more rapid and intense uptake of contrast, as well as a more rapid washout compared with the normal peripheral zone. However, histopathologic confirmation of these findings has been limited. This study strives to establish a correlation between K(trans) calculated from DCE-MRI data and the corresponding tissue histopathology. This will be achieved by acquiring needle biopsies with the APT-MRI (Access to Prostate Tissue under MRI-guidance) system in accurate spatial and temporal reference to DCE-MR images. The study will accrue 80 patients over a 2-year period with the primary analysis relating K(trans) to the probability of malignancy using Generalized Estimating Equations. Patients who have undergone a TRUS-guided biopsy for suspected prostate cancer or patients with a pathological diagnosis of prostate cancer will be potential candidates for enrollment. Prior to the procedure, blood will be drawn and urine collected to measure PSA level and for protein profiling. Patients will then undergo endorectal coil MR imaging of the prostate gland, including conventional anatomic imaging and dynamic-contrast-enhanced MRI. During MR imaging, 4 to 10 needle biopsy cores of the prostate will be obtained using a trans-rectal needle guide system (APT-MRI). The ability to obtain prostate biopsy cores from all prostatic subzones and sites of interest will be documented, as will the overall procedure time and acute toxicities associated with the procedure. Histopathology and laboratory results of needle core biopsies will be compared to corresponding DCE-MRI measurements, prior TRUS-biopsy results, and/or prostatectomy specimens. This procedure may be repeated at a later time through the patient's course of observation, therapy, or follow up. This is not a therapeutic trial. Patients admitted to this protocol will only be admitted to other protocols of experimental treatments if they also specifically meet the eligibility criteria for those protocols. Patients may derive benefit from the MRI-guided biopsy, which will be stated in the protocol consent document.