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Urinary Creatine Riboside Complements PSA to Improve Disease Detection in the Diagnostic Gray Zone of Prostate Cancer

Patel DP, Casiano AS, Toulabi L, Khan M, Dorsey TH, Mathé EA, Harris CC, Wang XW et al.

2026

668 participants

Abstract

Circulating prostate-specific antigen (PSA) discriminates poorly in the diagnostic gray zone (3.0–9.99 ng/mL), where ~75% of biopsies yield no clinically significant prostate cancer (PCa). We evaluated whether urinary creatine riboside (CR), a tumor-derived metabolite excreted through the prostatic urethra, complements PSA for gray-zone detection and independently predicts prostate-cancer-specific mortality (PCSM). In the NCI-Maryland PCa Case-Control Study (951 cases, 962 controls; 47.6% African American men; median follow-up 11.5 years), urinary CR was quantified by UPLC-MS/MS. Within the PSA gray zone ( n = 668), urinary CR was complementary to PSA, with markedly higher single-marker discrimination than PSA (AUC 0.93, 95% CI 0.88–0.98 vs 0.77, 0.66–0.89) and additive when combined (ΔAUC +0.17, p < 0.001; 91.4% sensitivity at 80% specificity). After adjustment for 11 clinical and sociodemographic covariates, urinary CR independently predicted PCSM complementary to PSA (Fine–Gray SHR 1.72, 1.35–2.19 for CR; 1.35, 1.08–1.68 for PSA; Harrell’s C 0.85 for CR + PSA vs 0.77 for PSA alone), with strongest signal in African American men (SHR 2.43, 1.57– 3.75 for CR). We conclude that urinary CR is a candidate non-invasive biomarker complementary to PSA — improving gray-zone triage and predicting PCSM; prospective validation in biopsy-referred cohorts is warranted.

How strong is the evidence?

Evidence Hub reads this as a case-control. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 668 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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