Stockholm3 Test is NOT for Monitoring Prostate Cancer
The Stockholm3 test is designed for initial prostate cancer detection and biopsy decision-making in men aged 50-69 years, not for monitoring established prostate cancer. This is a critical distinction that must be understood to avoid misuse of this diagnostic tool.
What Stockholm3 Actually Does
The Stockholm3 test is a blood-based risk prediction model that combines:
- Plasma protein biomarkers (PSA, free PSA, intact PSA, hK2, MSMB, MIC1) 1, 2
- Genetic polymorphisms (232 SNPs) 1, 2
- Clinical variables (age, family history, previous prostate biopsy, prostate exam) 1, 2
Its validated purpose is to predict the risk of clinically significant prostate cancer (Gleason Grade Group ≥2) in men being considered for initial or repeat prostate biopsy 3, 1, 2.
Clinical Performance for Detection (Not Monitoring)
In the primary validation study, Stockholm3 demonstrated:
- AUC of 0.74 for detecting Gleason score ≥7 cancer versus 0.56 for PSA alone 1, 2
- At equivalent sensitivity to PSA ≥3 ng/mL, Stockholm3 reduced biopsies by 32% and avoided 44% of benign biopsies 1, 2
- In a German validation cohort, Stockholm3 detected 92% of clinically significant cancers while reducing unnecessary biopsies by 52% 3
Why This Test Cannot Monitor Prostate Cancer
Common Pitfall: Confusing detection tools with monitoring tools. Stockholm3 was developed and validated exclusively in men without known prostate cancer who were being evaluated for possible disease 1, 2, 4. The test has never been studied or validated for:
- Monitoring disease progression in diagnosed patients
- Assessing treatment response
- Detecting biochemical recurrence
- Guiding active surveillance decisions in men with known cancer
What Should Be Used for Monitoring Instead
For men with established prostate cancer diagnosis:
Active Surveillance Monitoring should include 5:
- Serial PSA measurements (not Stockholm3)
- Periodic prostate biopsies
- Digital rectal examination
- Clinical assessment of disease progression
Post-Treatment Monitoring relies on 5:
- Serial PSA measurements for biochemical recurrence (PSA >0.2 ng/mL after prostatectomy)
- Clinical examination
- Imaging when indicated
The Correct Clinical Context for Stockholm3
Stockholm3 should only be considered in these specific scenarios 1, 2, 4:
- Men aged 50-69 years without prior prostate cancer diagnosis
- Elevated PSA levels requiring biopsy decision
- Men with previous negative biopsies being considered for repeat biopsy
- Initial risk stratification to reduce unnecessary biopsies
The test performs best when used at a threshold of ≥15 for recommending biopsy, which maintains high sensitivity (92%) for clinically significant disease while substantially reducing unnecessary procedures 3.
Comparison to Other Biomarkers
Unlike Stockholm3, the PCA3 test has been evaluated (though with insufficient evidence) for some monitoring applications 5, 6:
- PCA3 has FDA approval specifically for repeat biopsy decisions in men ≥50 years with prior negative biopsy 6
- Even PCA3 lacks evidence for determining disease aggressiveness or guiding treatment decisions 6
- Neither test should replace standard PSA monitoring in diagnosed patients
Bottom line: Stockholm3 is a pre-diagnostic risk stratification tool, not a monitoring test. Using it to monitor known prostate cancer would be off-label use without any supporting evidence and could lead to inappropriate clinical decisions.