Underestimation of Prostate Cancer Grade in Transperineal Fusion Biopsy and Its Predictive Factors: Correlation of Biopsy Findings with Post-Da Vinci Radical Prostatectomy Specimens.

: An accurate preoperative assessment of prostate cancer malignancy is crucial for risk stratification and selection of the optimal treatment strategy. This study assessed the concordance of Gleason scores between MRI-TRUS fusion biopsy and radical prostatectomy specimens, and identified clinical and histopathological factors associated with post-procedural Gleason score upgrading. : This retrospective analysis involved patients who underwent transperineal MRI-TRUS fusion biopsy followed by radical prostatectomy from 2020 to 2025. Concordance, upgrading, and downgrading of the Gleason score were assessed by comparing biopsy results with the final histopathological examination. Clinical parameters (age, PSA level, prostate volume, and PSA density) and histopathological features of biopsies (Gleason score and percentage of prostate lobes affected by cancer) were analyzed. Multivariate logistic regression models were stratified by PSA level (<10 ng/mL and >10 ng/mL). : Gleason score concordance was found in 53.1% of the 603 patients analyzed, upgrading in 29.9%, and downgrading in 17.1%. Higher Gleason scores on biopsy were independently associated with a lower risk of upgrading in the entire cohort and in both PSA subgroups. Larger tumor extent on biopsy was associated with a lower risk of upgrading, with heterogeneous dependencies between prostate lobes. The other clinical parameters showed no independent association with upgrading. : Gleason score upgrading remains common after radical prostatectomy. The risk of this progression is primarily related to the histopathological features of the biopsy rather than to baseline clinical parameters, reflecting the limitations of biopsy as a sampling method and the biological heterogeneity of prostate cancer.