Utility of early transperineal template-guided prostate biopsy for risk stratification in men undergoing active surveillance for prostate cancer

Abstract

Objective: To assess the accuracy and utility of routine multiparametric magnetic resonance imaging (mpMRI) and transperineal template-guided prostate biopsy (TPB) after enrolment in active surveillance (AS).

Patients and methods: From April 2012 to December 2016 consecutive men from our single institution, diagnosed with low- or intermediate-risk prostate cancer on transrectal ultrasonography-guided biopsy, were offered further staging with early mpMRI and TPB within 12 months of diagnosis. Data were collected prospectively. Eligibility criteria comprised: age ≤77 years; Gleason score ≤3 + 4; clinical stage T1-T2; PSA ≤15 ng/mL; and <50% positive biopsy cores.

Results: A total of 208 men were enrolled, including 196 with Gleason score 3 + 3 and 12 with Gleason score 3 + 4 disease. The median (range) number of TPB cores was 50 (17-161), with a mean TPB core density of 1.2 cores/cm³ prostate volume. A total of 83 men (39.9%) underwent histopathological upgrading after TPB, including 76 men (38.8%) with Gleason score 3 + 3 disease and seven men (58.3%) with Gleason score 3 + 4 disease. Of these, 26 (31.3%) were found to harbour primary pattern Gleason grade ≥4 disease. In all, 24 (28.9%) upgraded cases had Prostate Imaging Reporting and Data System (PI-RADS) score 1 or 2 lesions on mpMRI, including five men with Gleason score ≥4 + 3 disease. Of these, 14 (58.3%) had a prostate-specific antigen (PSA) density of ≥0.15, including four out of the five men with Gleason ≥4 + 3 disease. Overall there was a change in prostate cancer management in 77 men (37.0%) after TPB.

Conclusions: Early TPB during AS is associated with significant upgrading and a change in treatment plan in over a third of men. If TPB was omitted in men with a PI-RADS score <3 and a PSA density <0.15, 12% of those harbouring more significant disease would have been misclassified.

Keywords: active surveillance; prostate cancer; risk stratification; transperineal template-guided prostate biopsy; upgrading.