Defining the learning curve for multi-parametric MRI of the prostate using MRI-TRUS fusion guided transperineal prostate biopsies as a validation tool - Abstract

OBJECTIVES: To determine the accuracy of multiparametric Magnetic Resonance Imaging (mpMRI) during the learning curve of radiologists using MRI targeted, transrectal ultrasound guided transperineal fusion biopsy (MTTP) for validation.

MATERIAL AND METHODS: Prospective data on 340 men who underwent mpMRI (T2 weighted and DW-MRI) followed by MTTP prostate biopsy, was collected according to Ginsburg and STARD standards. MRI were reported by two experienced radiologists and scored on a Likert scale. Biopsies were performed by consultant urologists blinded to the MRI result and men had both targeted and systematic sector biopsies which were reviewed by a dedicated uropathologist. The cohorts were divided into groups representing five consecutive time intervals in the study. Sensitivity and specificity of positive MRI reports, Prostate cancer (CaP) detection by positive MRI, distribution of significant Gleason score and negative MRI with false negative for CaP were calculated. Data were sequentially analyzed and the learning curve was determined by comparing the first and last group.

RESULTS: We detected a positive mpMRI in 64 patients from group A (91%) and 52 patients from group E (74%). CaP detection rate on mpMRI increased from 42% (27/64) in group A to 81% (42/52) in group E (p value < 0.001). CaP detection rate by targeted biopsy increased from 27% (17/64) in group A to 63% (33/52) in group E (p value < 0.001). The negative predictive value of MRI for significant cancer (> Gleason 3+3) was 88.9% in group E compared to 66.6% in group A.

CONCLUSION: We demonstrate an improvement in detection of CaP for MRI reporting over time, suggesting a learning curve for the technique. With an improved negative predictive value for significant cancer, decision for biopsy should be based on patient/surgeon factors and risk attrubutes alongside the MRI findings.

Written by:
Gaziev G, Wadhwa K, Barrett T, Koo BC, Gallagher FA, Serrao E, Frey J, Seidenader J, Carmona L, Warren A, Gnanapragasam V, Doble A, Kastner C.   Are you the author?
Department of Urology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.

Reference: BJU Int. 2014 Aug 7. Epub ahead of print.
doi: 10.1111/bju.12892

PubMed Abstract
PMID: 25099182 Prostate Cancer Section