PSMA PET found more significant cancers than MRI targeting in equivocal PI-RADS 3 lesions

Design

Single-centre prospective paired diagnostic study

Population

66 biopsy-eligible men with PI-RADS 3 lesions and at least one high-risk feature

Primary outcome

Detection of clinically significant prostate cancer

Effect

PSMA-targeted 15% vs MRI-targeted 6%; difference 9% (95% CI 2% to 18%)

This single-centre prospective paired study enrolled biopsy-eligible men with an equivocal PI-RADS 3 lesion and at least one high-risk feature. All had PSMA PET/MRI before transperineal biopsy, which included MRI-targeted cores, PSMA-targeted cores where the scan was positive, and systematic cores. Sixty-six of 83 men completed the pathway.

PSMA PET was positive in 21 men (32%). PSMA-targeted biopsy found clinically significant cancer in 10 men (15%) against 4 (6%) with MRI-targeted biopsy, a difference of 9 percentage points (95% CI 2 to 18). Sensitivity and negative predictive value of PSMA PET were both 100%, and specificity 82%. None of the 45 men with a negative scan had significant cancer.

PI-RADS 3 lesions are a frequent source of uncertainty and unnecessary biopsies. These results are promising, but 66 men from one centre using one tracer are not enough to justify skipping biopsy on a negative scan, as the authors themselves say. PSMA PET access and cost also limit its use in India.

• Consider PSMA PET in men with PI-RADS 3 lesions and high-risk features where available, as a research-stage triage tool.
• Continue to biopsy PI-RADS 3 lesions with high-risk features under current practice; this study does not justify omitting biopsy.
• Use PSA density and other risk factors to decide which PI-RADS 3 lesions need biopsy.
• Watch for larger multicentre studies before changing pathways.

Why it matters

Equivocal MRI lesions generate many negative biopsies; a reliable rule-out test would spare men that procedure.

Don't overread it

With 66 men and few cancers, a 100% negative predictive value is fragile; one missed cancer would change it.

The statistics, in plain English

A negative predictive value of 100% came from 45 men with no significant cancer. With so few cancers overall (10), the true value in a larger group could be meaningfully lower.

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