- Design
- Prospective multicentre diagnostic trial
- Population
- 199 men with ISUP GG1 prostate cancer on active surveillance
- Primary outcome
- Upgrading to GG2 or higher at surveillance biopsy
- Effect
- Stockholm3 ≥15: sensitivity 0.93, NPV 0.87; 19% biopsies spared
The prospective STHLM3-AS NorDCaP trial, published in July, gave 199 men with grade group 1 prostate cancer on active surveillance in Sweden, Denmark and Norway a Stockholm3 blood test before their surveillance biopsy.
36% were upgraded. At a threshold of 15, Stockholm3 had sensitivity 0.93 and negative predictive value 0.87, and would have spared 19% of biopsies, missing five upgrades — none grade group 3 or higher. Its AUC (0.71) was similar to PSA density (0.71) and MRI PI-RADS 3 or more (0.72).
Stockholm3 is not available in India. The practical lesson is that combining PSA density and MRI already gives similar discrimination and can guide who needs a surveillance biopsy.
- Use PSA density and MRI together to decide the timing of surveillance biopsy.
- Consider a blood-based risk test where available as an additional input.
- Do not omit biopsy on one negative marker alone.
- Document the reasoning for deferring a scheduled biopsy.
Why it matters
Repeated surveillance biopsies drive men off active surveillance, and fewer of them could keep more men on it.
Don't overread it
199 men in one trial; an AUC of 0.71 is only moderate discrimination.
The statistics, in plain English
Sensitivity of 0.93 means 93% of upgrades were flagged. Specificity of 0.26 means most men without upgrading were still flagged for biopsy, which is why only 19% were spared.
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