Magnetic resonance imaging and spectroscopic imaging: Improved patient selection and potential for metabolic intermediate endpoints in prostate cancer chemoprevention trials

In the design of prostate cancer chemoprevention trials there is a clear ne ed for improved patient selection and risk stratification, as well as the u se of biomarkers that could provide earlier assessment of therapeutic effic acy. Studies in preprostatectomy patients have indicated that the metabolic information provided by 3-dimensional magnetic resonance spectroscopic ima ging (3D-MRSI] combined with the morphologic information provided by magnet ic resonance imaging (MRI) can improve the assessment of cancer location an d extent within the prostate, extracapsular spread, and cancer aggressivene ss. Additionally, pre- and posttherapy studies have demonstrated the potent ial of MRI/3D-MRSI to provide a direct measure of the presence and spatial extent of prostate cancer after therapy, a measure of the time course of re sponse, and information concerning the mechanism of therapeutic response. T hese studies suggest that the addition of MRI/3D-MRS data to prostate-speci fic antigen and biopsy data may improve patient selection and risk stratifi cation for chemoprevention trials, improve tissue sampling for ex vivo mole cular marker analysis, and provide shorter-term endpoints in chemopreventio n trials. However, future studies are necessary to establish the ability of MRI/3D-MRSI to accurately assess patients with premalignant or very early malignant changes, to validate metabolic markers as intermediate endpoints in chemoprevention trials, and to correlate metabolic endpoints with other promising intermediate biomarkers. (C) 2001, Elsevier Science Inc.