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A multi-marker blood test tested in a large Swedish trial identified substantially more cases of potentially life‑threatening prostate cancer than the long‑standing PSA screen, suggesting a route to earlier, more precise detection without a rise in unnecessary follow-up procedures. The findings, published this week in the Annals of Internal Medicine, arrive as experts warn metastatic prostate cancer rates have been climbing — a trend that makes better screening tools urgent.
Trial results and what they mean
Researchers at Karolinska Institutet enrolled more than 12,000 men, mostly from Sweden and other European countries, aged 50 to 74 and followed them for two years. Every participant received both the conventional test and the new assessment, known as Stockholm3. During the monitoring period, 443 men were diagnosed with what the investigators classified as aggressive prostate cancer.
The study reports that Stockholm3 identified about 90% of those aggressive cases, compared with roughly 74% detected by the standard PSA blood test. The new test missed markedly fewer serious cancers, while the rates of men flagged as high risk — who would typically undergo further imaging or biopsy — remained similar between the two tests.
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- Participants: >12,000 men, ages 50–74
- Follow-up: 2 years
- Aggressive cases detected: 443
- Detection rate: Stockholm3 ~90% vs PSA ~74%
- False high‑risk classification: comparable between tests
Clinical implications
A more selective screening tool could change how clinicians triage men for MRI and invasive sampling. When aggressive prostate tumors are caught while still confined to the gland, five‑year survival is near complete — a central reason researchers see value in a test that finds more clinically significant cancers earlier.
Thorgerdur Palsdottir, a co‑author from Karolinska’s Department of Medical Epidemiology and Biostatistics, said the trial shows the test can single out the cancers that matter most without adding follow‑up burden. Another investigator, Dr. Vigneswaran, stressed that while PSA has been the dominant screening tool since the 1990s, it is imperfect: it can trigger costly, invasive workups, lead to overdiagnosis of indolent disease and still miss a portion of aggressive tumors.
Limits and next steps
The authors caution that Stockholm3 is still an investigational device in many markets. It is not currently sold in the United States, and the test does not replace a diagnostic biopsy, which remains the definitive method to confirm cancer.
The company developing Stockholm3 has said it will seek U.S. regulatory clearance and intends to produce additional data — including studies in American populations — to support such an application.
Experts say broader validation is needed across diverse populations and longer follow‑up to understand how the test affects downstream outcomes, such as the number of biopsies performed, treatment decisions and long‑term survival. Still, the new evidence raises the possibility of refining prostate cancer screening to prioritize detection of curable, aggressive disease while limiting unnecessary procedures.
