Gleason score determination with TRUS-MRI fusion guided prostate biopsies: are we gaining in accuracy?

OBJECTIVE - to evaluate the accuracy of prostate MRI-TRUS targeted biopsy (TB) for Gleason score determination.

PATIENTS AND METHODS - we selected 125 consecutive patients treated with radical prostatectomy (RP) for a clinically localized prostate cancer diagnosed on MRI-TRUS TB and/or systematic biopsy. On multiparametric MRI (mpMRI), each suspicious area was graded according to the PI-RADS score. A correlation analysis between mpMRI and pathological findings was performed. Factors associated with Gleason score determination accuracy on TB were statistically assessed.

RESULTS - pathological analysis of RP specimens detected a total of 230 tumor foci. mpMRI detected a total of 151 suspicious areas. Of these, TB showed 126 cancer foci, in 115 patients, and detected the index lesion in all of them. The primary Gleason grade, secondary Gleason grade and Gleason score of the 126 individual tumors was determined accurately in 114 (90%), 75 (59%) and 85 (67%) cases, respectively. Maximal Gleason score was determined accurately in 80 (70%) patients. Gleason score determination accuracy on TB was significantly higher for low Gleason and high PI-RADS score tumors.

CONCLUSIONS - MRI-TRUS TB allowed for an accurate estimation of Gleason score in more than two third of patients. Gleason score misclassification was mostly due to a lack of accuracy for the determination of the secondary Gleason grade.

J Urol. 2015 Jul 9. pii: S0022-5347(15)04338-4. doi: 10.1016/j.juro.2015.07.021. [Epub ahead of print]

Lanz C1, Cornud F2, Beuvon F3, Lefèvre A2, Legmann P2, Zerbib M1, Delongchamps NB4.

1 Department of Urology, Cochin hospital, Paris Descartes University.
2 Department of Radiology, Cochin hospital, Paris Descartes University.
3 Department of Pathology, Cochin hospital, Paris Descartes University.
4 Department of Urology, Cochin hospital, Paris Descartes University; Inserm U1154, institut Necker-Enfants malades, Paris Descartes University.