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.
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.