Clinical implications of a multiparametric magnetic resonance imaging based nomogram applied to prostate cancer active surveillance.

Purpose: Multiparametric magnetic resonance imaging may be beneficial in the search for rational ways to decrease prostate cancer intervention in patients on active surveillance. We applied a previously generated nomogram based on multiparametric magnetic resonance imaging to predict active surveillance eligibility based on repeat biopsy outcomes.
Materials and Methods: We reviewed the records of 85 patients who met active surveillance criteria at study entry based on initial biopsy and who then underwent 3.0 Tesla multiparametric magnetic resonance imaging with subsequent magnetic resonance imaging/ultrasound fusion guided prostate biopsy between 2007 and 2012. We assessed the accuracy of a previously published nomogram in patients on active surveillance before confirmatory biopsy. For each cutoff we determined the number of biopsies avoided (ie reliance on magnetic resonance imaging alone without rebiopsy) over the full range of nomogram cutoffs.
Results: We assessed the performance of the multiparametric magnetic resonance imaging active surveillance nomogram based on a decision to perform biopsy at various nomogram generated probabilities. Based on cutoff probabilities of 19% to 32% on the nomogram the number of patients who could be spared repeat biopsy was 27% to 68% of the active surveillance cohort. The sensitivity of the test in this interval was 97% to 71% and negative predictive value was 91% to 81%.
Conclusions: Multiparametric magnetic resonance imaging based nomograms may reasonably decrease the number of repeat biopsies in patients on active surveillance by as much as 68%. Analysis over the full range of nomogram generated probabilities allows patient and caregiver preference based decision making on the risk assumed for the benefit of fewer repeat biopsies.
(Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)