Risk stratification of 'equivocal' PI-RADS lesions in mp-MRI of the prostate

To systematically analyze patients with PI-RADS-3-lesions (called 'equivocal' according to PI-RADS v2) in multiparametric prostate MRI (mp-MRI) and MR-targeted plus systematic transrectal ultrasound-guided (TRUS-GB) biopsies as reference standard.

One hundred and twenty consecutive patients with a PI-RADS overall score of 3 after mp-MRI (T2WI, DWI, DCE-MRI) at 3T and subsequent targeted MRI/US fusion-guided (FUS-GB) plus systematic 12-core TRUS-GB were retrospectively included in this study. As endpoints prostate cancer (PCa) detection rates, distribution of Gleason scores, location of PCa, and risk stratification by subgroup analyses were defined.

PCa was detected in 13 of 118 patients (detection rate 11%) including five patients with a Gleason score (GS) ≥3+4=7 (4.2%). 1.4% of the lesions within the transition zone (3/212) and 9.4% within the peripheral zone (6/64) were positive for PCa. Patients with PCa showed in 54% MRI patterns of peripheral prostatitis combined with diffuse stromal hyperplasia. Prostate volume was significantly lower in PCa patients (p=0.015), whereas differences in PSA levels were not statistically significant (p=0.87). PSA density was higher in patients with PCa (0.19 vs. 0.12 ng/ml/ml).

In patients with a PI-RADS overall score of 3 low-grade PCa (GS 3+3=6) can occur. PCa with a GS ≥3+4=7 can be detected in mp-MRI with a high degree of certainty, GS ≥4+3=7 PCa is very unlikely in PI-RADS-3-lesions. Therefore, these patients primarily should receive follow-up MRI. In patients with a combination of MRI aspects of extensive prostatitis and diffuse stromal hyperplasia, low prostate volume, and/or high PSA density biopsy might be considered.

The Journal of urology. 2017 Sep 20 [Epub ahead of print]

T Ullrich, M Quentin, C Arsov, A K Schmaltz, A Tschischka, N Laqua, A Hiester, D Blondin, R Rabenalt, P Albers, G Antoch, L Schimmöller

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf, Germany., University Dusseldorf, Medical Faculty, Department of Urology, D-40225 Dusseldorf, Germany.


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