Comparative diagnostic accuracy of multiparametric-MRI and Micro-ultrasound for clinically significant prostate cancer-a bivariate meta-analysis of prospective studies.

[BACKGROUND] Prostate cancer (PCa) remains a leading cause of cancer-related mortality in men. While multiparametric MRI (mpMRI) is an established tool for detecting clinically significant PCa (csPCa), it is limited by cost, access, and acquisition time. Micro-ultrasound (Micro-US) offers real-time imaging with potential advantages in accessibility and integration into routine care. This systematic review and meta-analysis (SR/MA) aimed to compare the diagnostic accuracy of Micro-US versus mpMRI in detecting csPCa, based exclusively on prospective evidence.

[METHODS] A protocol-registered SR/MA (INPLASY202540027) was conducted following PRISMA and PICOTT frameworks. Prospective cohort studies and randomized controlled trials published between 2012 and March 2025 comparing micro-US and mpMRI for csPCa detection, using biopsy or prostatectomy specimens as reference standards, were included. Bivariate random-effects models were used to estimate pooled sensitivity, specificity, and summary ROC curves. Positive/negative predictive values (PPV/NPV) were calculated using pooled prevalence and literature-based prevalence values. Meta-regression assessed modality differences and potential effect modifiers.

[RESULTS] Eight prospective studies (n = 2626 patients) met the inclusion criteria, 1 randomized controlled trial and 7 prospective cohorts. Micro-US demonstrated a pooled sensitivity of 0.87 (95%CI: 0.80-0.92) and specificity of 0.25 (95% CI: 0.17-0.36), while mpMRI showed a sensitivity of 0.88 (95% CI: 0.81-0.93) and specificity of 0.30 (95% CI: 0.18-0.46). sROC confidence regions overlapped for both modalities. Meta-regression detected no significant difference in sensitivity (P = 0.72) but a significant difference in specificity favoring mpMRI (P = 0.003). PPVs were modest (0.41-0.46), and NPVs were high (0.72-0.80) across prevalence scenarios.

[CONCLUSION] Micro-US demonstrates sensitivity comparable to mpMRI for csPCa screening before confirmatory biopsy, although mpMRI retains superior specificity. Micro-US may serve as an accessible alternative or complementary modality, but further high-quality prospective studies are needed to strengthen comparative evidence.