- Design
- Single-centre prospective paired diagnostic study
- Population
- 66 biopsy-eligible men with PI-RADS 3 lesions and ≥1 high-risk feature
- Primary outcome
- Clinically significant cancer detection: PET-targeted vs MRI-targeted biopsy
- Effect
- 15% vs 6% (difference 9%, 95% CI 2–18%); NPV 100%
A single-centre prospective paired study enrolled biopsy-eligible men with an equivocal PI-RADS 3 lesion and at least one high-risk feature. Each had PSMA PET/MRI before transperineal MRI-targeted, PET-targeted (if positive) and systematic biopsy. Sixty-six completed the protocol.
PSMA PET was positive in 32%. PET-targeted biopsy found clinically significant cancer in 15% of men, compared with 6% for MRI-targeted biopsy (difference 9%, 95% CI 2% to 18%). PET had sensitivity 100%, specificity 82% and negative predictive value 100%. A negative PET would have spared 45 of 66 men (68%) a biopsy, and none of them had significant cancer.
The numbers are small, events few, and the tracer used is not widely available. The authors call for multicentre studies before biopsy deferral based on a negative scan.
For now, it suggests a role for PSMA PET as a triage step in PI-RADS 3 lesions where available, within research or carefully audited pathways.
- Consider PSMA PET/MRI for PI-RADS 3 lesions in men with additional risk features, where available.
- Target biopsy to PET-positive areas as well as the MRI lesion.
- Do not yet defer biopsy on a negative PET outside a study or audited pathway.
- Weigh PSMA PET cost and access against biopsy in local practice.
Why it matters
PI-RADS 3 lesions are the commonest source of uncertain biopsies, and a reliable rule-out test would spare many men.
Don't overread it
Sixty-six men from one centre; a 100% negative predictive value rests on very few cancers.
The statistics, in plain English
A negative predictive value of 100% means no man with a negative PET had significant cancer here, but with only 10 cancers in total the true value could be lower. The 9% detection difference has a confidence interval from 2% to 18%.
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