- Design
- Biomarker model derivation with external validation across 11 practices and direct head-to-head comparison with multiparametric MRI
- Population
- 330 patients with grade group 1 prostate cancer scheduled for active surveillance biopsy; 85% had prebiopsy MRI; all had 12 or more systematic cores plus targeted cores of PI-RADS 3 or above lesions
- Primary outcome
- Prediction of upgrading to grade group 3 or above and grade group 2 or above at biopsy
- Effect
- Area under the curve 0.82 vs 0.73 (grade group 3 or above) and 0.74 vs 0.64 (grade group 2 or above); 64% of unnecessary biopsies avoided missing 3.2% of grade group 3 upgrades, versus PI-RADS 3 or above avoiding 50% and missing 18%
Active surveillance depends on repeated biopsies, and repeated biopsies are the reason patients leave surveillance. Multiparametric MRI was supposed to reduce them and has been an imperfect filter. This study derived and externally validated a urine biomarker model, MyProstateScore 2.0 Active Surveillance, requiring no digital rectal examination, and compared it head to head with MRI across 11 practices.
The validation cohort was 330 patients with grade group 1 cancer scheduled for a surveillance biopsy; 85% had prebiopsy MRI. On biopsy, 31 (9.4%) upgraded to grade group 3 or above and 123 (37%) to grade group 2 or above. The urine test gave a higher area under the curve than MRI for both thresholds: 0.82 versus 0.73 for grade group 3 or above, and 0.74 versus 0.64 for grade group 2 or above.
The clinical translation is where it matters. Using the urine test to decide on biopsy would have avoided 64% of unnecessary biopsies while missing 3.2% of grade group 3 upgrades and 4.9% of grade group 2 upgrades. Using PI-RADS 3 or above as the trigger would have missed 18% of grade group 3 upgrades and 35% of grade group 2 upgrades, while avoiding fewer biopsies (50%). Performance held across confirmatory and surveillance biopsies and in Black and non-Black patients - the latter matters because prostate biomarkers have repeatedly failed to validate across populations.
The honest caveats: patients were selected because they were already scheduled for biopsy, all had grade group 1 disease, and Indian validation does not exist. The test is commercially available in the US and not in India, where the relevant comparison is against a surveillance protocol that often has no MRI at all.
So where this test is available, it should displace MRI as the primary trigger for surveillance biopsy on this evidence. Where it is not, the finding still argues against treating a reassuring MRI as sufficient reason to skip a scheduled biopsy - it missed nearly a fifth of the upgrades that mattered.
- Do not skip a scheduled surveillance biopsy on a negative MRI alone - 18% of grade group 3 upgrades were missed
- Where the urine test is available, use it as the primary trigger for surveillance biopsy
- Quote the residual risk: about 3% of significant upgrades were missed by the urine test
- Note the population - all had grade group 1 disease and were already due for biopsy
- No Indian validation exists; the test is not available here
The statistics, in plain English
An area under the curve of 0.82 against 0.73 means the urine test ranks an upgrading patient above a non-upgrading one 82% of the time versus 73% for MRI - a meaningful gap, though both are far from perfect. The clinically useful pair of numbers is biopsies avoided against upgrades missed: 64% and 3.2% for the urine test, 50% and 18% for PI-RADS, and it is the second figure that should decide, because a missed grade group 3 cancer is the harm surveillance exists to prevent. With only 31 grade group 3 upgrades in the cohort, the 3.2% miss rate rests on one patient, so its precision is poor even though the comparison with MRI is stark.
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