Tri-modal PSMA PET/CT-MRI-US fusion biopsy for clinically significant prostate cancer: a prospective paired diagnostic study.

In 30 seconds

This prospective, single-centre paired diagnostic accuracy study compared tri-modal PSMA PET/CT-MRI-ultrasound fusion biopsy with MRI-ultrasound fusion and systematic biopsy in 308 biopsy-naive men. The primary outcome was patient-level detection of clinically significant prostate cancer (ISUP grade group ≥2). Tri-modal fusion detected 4.9% more clinically significant cancers than MRI-ultrasound fusion (95% confidence interval 2.4%-7.3%; P < 0.001; number needed to biopsy 20.5). Gains were most evident in PSMA-positive lesions < 10 mm and PI-RADS 4 lesions. A simulated risk-guided strategy suggested potential biopsy reduction, but requires validation.

Key findings

• Tri-modal fusion detected 4.9% more clinically significant prostate cancer than MRI-ultrasound fusion (95% confidence interval 2.4%-7.3%; P < 0.001).
• Detection gains were 8.3% for PSMA-positive lesions < 10 mm and 5.8% for PI-RADS 4 lesions.
• The PSMA imaging-based risk score had an area under the curve of 0.933, exceeding the discrimination of the PRIMARY and molecular imaging PSMA scores.
• In a retrospective test-set simulation, risk-guided biopsy would have avoided approximately 42% of biopsies while missing 2.3% of clinically significant cancers.

Why it matters

The findings suggest that adding PSMA imaging to MRI-ultrasound fusion may improve detection beyond MRI-targeted biopsy, including for small PSMA-positive and PI-RADS 4 lesions. The risk score and simulated biopsy reduction also raise the possibility of more selective biopsy strategies. However, the evidence comes from a single-centre study, and the proposed approach is not yet validated for routine use.

What to keep in mind

The study was single-centre, and the test set used for the retrospective risk-guided simulation was small. The authors state that multicentre validation is needed before clinical adoption.