Does It Make Sense to Perform Prostate Magnetic Resonance Imaging in Men with Normal PSA (<4 ng/mL)?

Area of Science:

• Radiology
• Oncology
• Urology

Background:

• Normal prostate-specific antigen (PSA) levels do not always exclude clinically significant prostate cancer (csPC).
• Prostate MRI is increasingly used for prostate cancer detection, but its role in men with normal PSA requires evaluation.

Purpose of the Study:

• To assess the performance and diagnostic relevance of Magnetic Resonance Imaging (MRI) for detecting csPC in men with normal PSA levels (<4 ng/mL).
• To analyze MRI performance across different PSA subgroups and identify reasons for referral.

Main Methods:

• Retrospective analysis of 148 men with PSA < 4 ng/mL referred for prostate MRI, with histopathology or 2-year follow-up as the reference standard.
• Prostate MRIs were reported using the Prostate Imaging and Reporting Data System (PI-RADS); PI-RADS ≥ 3 was considered positive.
• Performance was evaluated for detecting International Society of Urological Pathology (ISUP) grade group ≥ 2 and ≥ 3 csPC.

Main Results:

• Overall, 18.9% of men had ISUP ≥ 2 csPC detected by MRI with 92.9% sensitivity and 39.4% positive predictive value (PPV).
• For ISUP ≥ 3 csPC, MRI sensitivity was 100% but PPV was 21.2%.
• In men with PSA < 2 ng/mL, no csPC was found, and MRI yielded false positives in 33.3% of cases.

Conclusions:

• Prostate MRI is valuable for detecting csPC in men with normal PSA if other clinical suspicion factors are present.
• While MRI demonstrates high sensitivity, its low PPV necessitates careful interpretation to avoid unnecessary procedures.
• The value of MRI is limited in men with PSA < 2 ng/mL due to a high rate of false positives and absence of csPC.