- Design
- Single-centre prospective paired diagnostic study
- Population
- 66 biopsy-eligible men with PI-RADS 3 lesion and ≥1 high-risk feature
- Primary outcome
- Per-patient detection of clinically significant prostate cancer
- Effect
- PSMA-targeted 15% vs MRI-targeted 6%; difference 9% (95% CI 2–18)
PI-RADS 3 lesions are the grey zone of prostate MRI: most are not significant cancer, but some are. This single-centre prospective paired study took 66 biopsy-eligible men with an equivocal PI-RADS 3 lesion and at least one high-risk feature, and performed PSMA PET/MRI before transperineal biopsy. Every man had MRI-targeted and systematic biopsy, plus PSMA-targeted biopsy where the PET was positive.
PSMA PET was positive in 32%. PSMA-targeted biopsy found clinically significant cancer in 15% of men, against 6% for MRI-targeted biopsy (difference 9 points, 95% CI 2 to 18). In this cohort PSMA PET had 100% sensitivity, 82% specificity and 100% negative predictive value; 68% of men had a negative scan and none of them had significant cancer.
The result suggests PSMA PET can both find cancers MRI targeting misses and identify men who may not need biopsy. But with 66 men and 10 cancers, a 100% negative predictive value is fragile, and the authors themselves say deferral of biopsy should be tested in larger multicentre studies first. PSMA PET is costly and limited in availability in India.
- Consider PSMA PET-guided targeting for PI-RADS 3 lesions with high-risk features where PET is available.
- Continue to biopsy men with a negative PSMA PET until larger studies support deferral.
- Combine targeted and systematic sampling, as in the study.
- Discuss the cost and availability of PSMA PET with patients before referral.
- Use PSA density and other risk features to select men for added imaging.
Why it matters
It offers a way through the PI-RADS 3 dilemma that drives many unnecessary biopsies.
Don't overread it
This is a single-centre study of 66 men; the perfect negative predictive value is not yet a basis for avoiding biopsy.
The statistics, in plain English
The 9-point difference has an interval of 2 to 18, so a real advantage is likely but its size is uncertain. A 100% negative predictive value from 45 negative scans and few cancers overall could fall substantially in a larger group.
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