Natural History of Pathologically Benign Cancer Suspicious Regions on Multiparametric Magnetic Resonance Imaging Following Targeted Biopsy.

PURPOSE: We determined the natural history of pathologically benign cancer suspicious regions on multiparametric magnetic resonance imaging following targeted biopsy.

MATERIALS AND

METHODS

Between January 2012 and September 2014, 330 men underwent prostate multiparametric magnetic resonance imaging. A total of 533 cancer suspicious regions were identified and scored on a Likert scale of 1 to 5 based on suspicion for malignancy with 5 indicating the highest suspicion level. Following multiparametric magnetic resonance imaging all men underwent magnetic resonance imaging-ultrasound fusion targeted prostate biopsy using ProFuse software and the ei-Nav|Artemis system (innoMedicus, Cham, Switzerland), and a computer generated 12-core random biopsy. We analyzed a cohort of 34 men with a total of 51 cancer suspicious regions who had benign prostate biopsies and underwent repeat multiparametric magnetic resonance imaging and prostate specific antigen testing at 1 year. Changes in the greatest linear measurement, the suspicion score and serum prostate specific antigen were ascertained.

RESULTS

During 1 year the suspicion score distribution and the mean greatest linear measurement of the cancer suspicious regions decreased significantly (p <0.0001) while mean prostate specific antigen did not significantly change (p = 0.632). Two (3.9%), 15 (29.4%) and 34 cancer suspicious regions (66.7%) showed an increase, no change and decrease in suspicion score, respectively. No (0%), 21 (42.0%) and 29 cancer suspicious regions (58.0%) showed an increase of 20% or greater, no change and a decrease of 20% or greater in greatest linear measurement, respectively. Of the 2 cancer suspicious regions exhibiting an increased suspicion score neither showed a prostate specific antigen increase of 0.5 ng/ml or greater.

CONCLUSIONS

Our study provides compelling evidence that few benign cancer suspicious regions increase in suspicion score and/or the greatest linear measurement within 1 year independent of the baseline suspicion score. Therefore, routinely repeating multiparametric magnetic resonance imaging at 1 year in men with pathologically benign cancer suspicious regions should be discouraged since it is unlikely to influence management decisions.