Magnetic resonance imaging in active surveillance of prostate cancer: a systematic review

Context: There is great interest in using magnetic resonance imaging (MRI) for men on active surveillance for prostate cancer.

Objective: To systematically review evidence regarding the use of MRI in men with low- or intermediate-risk prostate cancer suitable for active surveillance.

Evidence acquisition: Ovid Medline and Embase databases were searched for active surveillance, prostate cancer, and MRI from inception until April 25, 2014 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses process. Identified reports were critically appraised according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria.

Evidence synthesis: A lesion on MRI suspicious for prostate cancer (positive MRI) is seen in two-thirds of men otherwise suitable for active surveillance. A positive MRI makes the identification of clinically significant disease at repeat biopsy more likely, especially when biopsies are targeted to suspicious MRI lesions. Radical prostatectomy data show that positive MRI is more likely to be associated with upgrading (Gleason score>3+3) than a negative MRI (43% vs 27%). A positive MRI is not significantly more likely to be associated with upstaging at radical prostatectomy (>T2) than a negative MRI (10% vs 8%). Although MRI is of interest in the monitoring of men on active surveillance, robust data on the use of repeat MRI in active surveillance are lacking. Prospective studies with clear definitions of radiological significance and progression are needed before this approach can be adopted.

Conclusions: MRI is useful for detection of clinically significant disease at initial assessment of men considering active surveillance. To use MRI as a monitoring tool in surveillance, it will be necessary to define both radiological significance and radiological progression.

Patient summary: This review assesses evidence for the use of magnetic resonance imaging (MRI) in men on active surveillance for prostate cancer. MRI at the start of surveillance can detect clinically significant disease in one-third to half of men. There are few data to assess the use of MRI as a monitoring tool during surveillance, so there is a need to define significant disease on MRI and significant changes over time.