The diagnostic accuracy of MRI PI-RADS scoring in a transperineal prostate biopsy setting - Abstract

OBJECTIVES: To determine the sensitivity, specificity of multiparametric MRI (mp-MRI) for significant prostate cancer with transperineal sector biopsy (TPB) as the reference standard.

PATIENTS AND METHODS: Consecutive men who presented for TPSB between July 2012 and November 2013 following mp-MRI (T2 and diffusion-weighted images, 1.5 Tesla scanner, 8-channel body coil) were included. A specialist uro-radiologist, blinded to clinical details, assigned qualitative PI-RADS (Prostate Imaging Reporting and Data System) scores on a Likert scale of 1 to 5 denoting the likelihood of significant prostate cancer with 1-highly unlikely, 3-equivocal, and 5-highly likely. Transperineal sector biopsies sampled 24-40 cores (depending on prostate size) per patient. Significant prostate cancer was defined as the presence of Gleason pattern 4 or cancer core length ≥6mm.   

RESULTS: Two hundred and one patients went on to analysis. Indications were: prior negative transrectal biopsy with continued suspicion of prostate cancer (103); primary biopsy (83); and active surveillance (15). Mean(±sd) age, PSA and prostate volumes were 65(±7) years, 12.8(±12.4)ng/mL and 62(±36)cm3 respectively. Overall, biopsies were benign, clinically insignificant and clinically significant in 124(62%), 20(10%) and 57(28%) men respectively. 2 of 88 men with PI-RADS score 1 or 2 had significant prostate cancer giving sensitivity (95% confidence intervals) 97%(87 to 99) and specificity 60%(51 to 68) at this threshold. ROC analysis gave an area under the curve (95% confidence intervals) of 0.89 (0.82 to 0.92). The negative predictive value of a PI-RADS score of ≤ 2 for clinically significant prostate cancer was 97.7%.

CONCLUSION: PI-RADS scoring performs well as a predictor for biopsy outcome and may be used in the decision making process for prostate biopsy.

Written by:
Grey A, Chana M, Popert R, Wolfe K, Liyanage S, Acher P.   Are you the author?
Southend University Hospital NHS Foundation Trust.

Reference: BJU Int. 2014 Jul 16. Epub ahead of print.
doi: 10.1111/bju.12862

PubMed Abstract
PMID: 25041307 Prostate Cancer Section