Blood-Based Biomarkers in Prostate Cancer

How to cite: Inman BA. Blood-Based Biomarkers in Prostate Cancer. Grand Rounds in Urology. October 2025. Accessed Jan 2026. https://grandroundsinurology.com/blood-based-biomarkers-in-prostate-cancer/

Summary

Brant A. Inman, MD, MS, FRCSC, Professor of Urology and Oncology, Western University, London, Canada, reviews commonly used serum biomarkers and explains how they improve risk stratification beyond prostate-specific antigen (PSA) alone.

Dr. Inman emphasizes that the primary clinical role of blood-based biomarkers is estimating the probability of prostate cancer at the diagnostic decision point. While biomarkers may also have future applications in prognosis, recurrence detection, and treatment selection, he focuses on how they inform biopsy decisions in everyday practice.

The presentation reviews five major blood-based approaches: total PSA and free PSA, Prostate Health Index (PHI), 4Kscore, Stockholm3, and IsoPSA. All of these tests incorporate PSA and free PSA, but differ in their inclusion of additional PSA isoforms, kallikrein-related markers, clinical variables, genetic information, or structural analysis of PSA. Dr. Inman explains PSA biology in detail, clarifying how prostate cancer alters the relative fractions of PSA isoforms compared with benign prostate tissue and why this underpins the performance of these tests.

By placing biomarkers within the National Comprehensive Cancer Network (NCCN) early detection pathways, Dr. Inman highlights a key decision point following confirmation of an elevated PSA. At this point, clinicians may choose between prostate MRI or a biomarker to determine whether biopsy is appropriate. Using a Prostate Cancer Prevention Trial risk calculator as an example, he demonstrates how adding free PSA substantially changes the estimated cancer risk and influences shared decision-making. Dr. Inman compares PHI and 4Kscore, noting similar diagnostic performance, highlights large prospective data supporting 4Kscore, and reviews emerging evidence for IsoPSA and Stockholm3.

He stresses that blood-based biomarkers consistently outperform PSA alone and are best used to guide decisions about when to biopsy or re-biopsy.

About The 12th Urology Today Conference:

Presented by chair Ryan P. Terlecki, MD, FACS, the 12th Urology Today conference was designed to keep urologists, urologic oncologists, and other healthcare providers educated on the most pertinent issues in urology practices. Areas of focus included urologic oncology, men’s health and reconstruction, female urology, pediatric urology, kidney stones and related conditions, and methods of providing the best care amidst the required logistics of the business side of medicine.

For further educational activities from this conference, visit our collection page.