Multiparametric MRI combined with PSA density as a noninvasive rule-out strategy in active surveillance for prostate cancer

Objective

To evaluate the diagnostic performance of multiparametric MRI (mpMRI), mpMRI combined with PSA density (PSAd) and combined biopsy (CBx) in detecting clinically significant prostate cancer (csPCa) in men undergoing active surveillance, using radical prostatectomy (RP) specimens as the reference standard.

Patients and Methods

In this prospective single-centre study, 91 patients with low-risk prostate cancer under active surveillance underwent mpMRI, PSAd measurement, CBx and ultimately RP. mpMRI was reported using PI-RADS v2.0, and PSAd was dichotomised at 0.12 ng/ml/cm³. Diagnostic accuracy was compared using ISUP grade ≥2 and ≥3 thresholds. Radical prostatectomy pathology served as the reference standard.

Results

For detecting ISUP ≥3 cancer, mpMRI combined with PSAd achieved the highest sensitivity (93.3%) and negative predictive value (94.4%). CBx demonstrated the highest specificity (88.2%) and overall diagnostic balance (Youden index = 0.348). mpMRI alone showed intermediate performance. Differences in classification between strategies were statistically significant (McNemar p < 0.001).

Conclusions

mpMRI combined with PSAd provides high sensitivity and negative predictive value for ruling out aggressive prostate cancer, supporting its use as a non-invasive triage tool in active surveillance. CBx remains the most specific method for histological confirmation. These strategies should be used complementarily to optimise decision-making in active surveillance protocols.