Magnetic resonance imaging target fusion biopsy vs. transrectal ultrasound-guided biopsy - A comparative study of ISUP score upgrading risk in the final radical prostatectomy specimen

Abstract

Objectives: The aim of this study was to com-Summary pare the risk of International Society of Urological Pathology (ISUP) score upgrading between magnetic resonance imaging targeted fusion biopsy (MRI-TB) and transrectal ultrasound-guided biopsy (TRUS-B) in the final radical prostatectomy (RP) specimen pathological report. Materials and methods: This retrospective single center study included 51 patients with prostate cancer (PCa) diagnosed with MRI-TB and 83 patients diagnosed with TRUS-B between October/2019 and July/2021. We compared the rates of ISUP score upgrading between both groups after robotic-assisted radical prostatectomy (RARP) and the specific transition of each ISUP score based on biopsy modality. The rate of ISUP score concordance and downgrading were also assessed. To define the intra and interobserver concordance for each ISUP score in biopsy and RP specimen for each biopsy modality, the Cohen’s Kappa coefficient was calculated. ISUP scores and biopsy modality were selected for multivariate analysis and a logistic regression model was built to provide independent risk factors of ISUP score upgrading. Results: The difference of the rate of upgrading between MRI-TB group and TRUS-B group was statistically significant (p = 0.007) with 42.2% of patients of TRUS-B group experiencing an upgrade in their ISUP score while only 19.6% in MRI-TB group. Concordance and downgrading rates did not statistically differ between the two groups. Strength of concordance using Cohen’s Kappa coefficient was fair in both groups but higher in MRI-TB group (TRUS-B group k = 0.230; p < 0.001; concordance: 47% vs. MRI/TB group k = 0.438; p < 0.001; concordance: 62.7%). Biopsy modality and ISUP 1 on biopsy were independent predictors of ISUP upgrading after RP. Conclusions: MRI-TB is highly accurate with lower risk of PCa upgrading after RP than TRUS-B. Patients with ISUP 1 on biopsy have greater susceptibility to upgrading their ISUP score.