ISOPSA Large Scale Prospective Validation Study: Performance of the ISOPSA Test in Patients Aged 50-69 Years

Document Type

Conference Proceeding

Publication Date

5-2025

Publication Title

Journal of Urology

Abstract

NTRODUCTION AND OBJECTIVE: IsoPSA is a novel structure-based (blood) assay with statistically significant negative and positive predictive characteristics for high-grade clinically actionable prostate cancer (Grade Group≥2). In this subgroup analysis, we aimed to assess the statistical performance of IsoPSA in patients aged 50-69 years. METHODS: From a large scale prospective validation study of IsoPSA, 750 patients with age≥50 years & total PSA≥4 ng/mL comprised the evaluable study population undergoing prostate cancer (PCa) early detection. All patients received prostate biopsy and IsoPSA. Patients and investigators were blinded to all IsoPSA results. IsoPSA performance in the subgroup of patients aged 50-69 years was assessed in relation to the high-grade PCa outcome on prostate biopsy by: 1) prevalence based likelihood ratio analysis of pre-test risk (prevalence) and post-test risk at an IsoPSA Index lower cutoff = 6.0and an IsoPSA Index upper cutoff = 10.0 2) sensitivity (SN) and negative predictive value (NPV) at the IsoPSA Index lower cutoff; specificity (SP) and positive predictive value (PPV) at the IsoPSA Index upper cutoff. RESULTS: Of 750 patients comprising the overall study population 501 (67%) had age 50-69 years. In this subgroup, IsoPSA displays highly statistically informative negative and positive predictive characteristics: 1) post-test risk point estimates at the lower IsoPSA Index cutoff of ≤6.0 (7.69%; 95% CI 2.88%-15.99%) and at the upper IsoPSA Index cutoff of >10.0 (44.70%; 95% CI 38.60%-50.91%) are substantially below and above the pre-test risk (prevalence) point estimate (30.14%), respectively. 2) pre-test risk point estimate falls outside of the 95% CI for post-test risk at both lower and upper IsoPSA Index cutoffs by likelihood ratio (LR) analysis. 3) IsoPSAI ndex SN and NPV at the lower cutoff=96.03% and 92.31%, respectively; SP and PPV at the upper cutoff=58.29% and 44.70%, respectively. CONCLUSIONS: IsoPSA displays highly statistically informative negative and positive predictive value for patients aged 50-69 years which aligns with the Early Detection of Prostate Cancer: AUA/SUO Guideline (2023) and the Recommendation Statement on Prostate Cancer: Screening (U.S. Preventive Services Task Force)

Volume

213

Issue

5S

First Page

e1094

Last Page

e1095

Comments

American Urological Association Annual Meeting, April 26-29, 2025, Las Vegas, NV

DOI

10.1097/01.JU.0001110100.38838.c8.27

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