Management of Radiologically Indeterminate Magnetic Resonance Imaging Signals in Men at Risk of Prostate Cancer

Background Multiparametric magnetic resonance imaging (mp-MRI) is becoming an increasingly important diagnostic tool for prostate cancer. So far there has been little focus on management for indeterminate mp-MRI results. Objective To describe outcomes for a cohort of men rated as having an indeterminate mp-MRI result. Design, setting, and participants Patients were identified retrospectively from a single UK centre between October 2010 and January 2015. Patients were included if they had a Likert score of 3/5 on a first MRI scan without any prior prostate biopsy. Patients were offered one of two initial management strategies. Strategy 1 was an immediate targeted biopsy of the MRI lesion. Strategy 2 was a surveillance process comprising prostate-specific antigen monitoring and/or mp-MRI at intervals of 6–12 mo, with biopsy on a for-cause basis. Outcome measurements and statistical analysis Cancer detection and treatment outcomes were compared for the two strategies. Results and limitations Of 168 patients, 73 (43%) chose strategy 1 and 95 (57%) chose strategy two. The overall proportion of men with clinically significant cancer detected was 14% (23/168). The risk profile for cancer identified in the initial surveillance group was similar to that identified in the immediate biopsy group. Limitations of the study include the short follow-up. Conclusions Men with indeterminate mp-MRI were willing to forego immediate biopsy for a strategy of surveillance involving PSA measurement and/or mp-MRI repeated at intervals. The risk profile of the cancers identified by both strategies appeared similar, but many men in the surveillance group avoided the risks, complications, and costs of biopsy. Long-term results are awaited. Patient summary This report compares two approaches for an uncertain magnetic resonance imaging result for clinically important prostate cancer: immediate biopsy versus surveillance with delayed biopsy if required. Delayed biopsy did not result in identification of cancer with adverse features, and many men benefited from avoiding a biopsy and its complications.