Elevated IsoPSA Selects for Clinically Significant Prostate Cancer Without a Preference for Any Particular Adverse...

To explore if elevated IsoPSA selects for particular adverse radiographic or histopathologic features among men destined to undergo radical prostatectomy (RP) because of clinically significant prostate cancer identified at biopsy.

Single center, retrospective review of patients who had undergone IsoPSA testing, prostate biopsy and RP at our institution from 2019-2021. A consecutive cohort of patients whom had undergone RP within the same period without pre-operative IsoPSA served as controls. Pre-operative prostate Magnetic Resonance Imaging (MRI) was included in our analysis. Adverse histopathologic and MRI features were compared between both groups. Concordance, downstaging, and upstaging grade group rates (GG) was evaluated. Pearson Chi-Square test was used to compare categorical variables, Wilcoxon-Rank sum test for quantitative variables, and binary logistic regression to identify predictors of upstaging at RP.

Eighty-three patients underwent IsoPSA and RP while 44 patients were controls. The IsoPSA group had significantly higher pre-operative PSA (IsoPSA group: 7.8 ng/mL vs Control group: 5.2 ng/mL, P<.001 ). Elevated IsoPSA index (>6.0) did not select for any specific adverse histopathologic features at RP. Excluding PSA density, elevated IsoPSA was not selective for adverse MRI features. There were no differences in concordance, downstaging, and upstaging GG rates from biopsy to RP. IsoPSA testing was not a predictor of GG upstaging (Odds Ratio: 0.63, P .58).

Elevated IsoPSA is a diagnostic tool that can detect clinically significant prostate at the time of biopsy. In doing so, it does not select for any particular adverse prostate MRI or pathologic feature at RP.