HMN 2026: How New blood test detects more high-risk prostate cancer cases

A new blood test may make it easier to detect the most dangerous forms of prostate cancer early. In a study from Karolinska Institutet, the Stockholm3 blood test detected more clinically significant cancer cases than the PSA test, without subjecting more men to unnecessary testing. The study is published in the Annals of Internal Medicine.

In a large population-based study involving 12,670 men ages 50–74, researchers at Karolinska Institutet in Sweden showed that the blood-based Stockholm3 test identified significantly more aggressive prostate cancers than traditional PSA testing. Stockholm3 detected 90% of aggressive cancer cases, compared with 74% for PSA.

Need for better methods

Prostate cancer is one of the most common forms of cancer among men globally. PSA testing has long been used for early detection, but it is controversial because it can both miss aggressive tumors and lead to unnecessary further investigations and biopsies. The new results suggest that Stockholm3 may offer a more accurate alternative.

“The major challenge in prostate cancer screening is not just to find more cancer cases, but to identify the cancers that are truly dangerous,” said Thorgerdur Palsdottir, a researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. “Our results show that Stockholm3 identifies significantly more aggressive cancer cases than PSA, without increasing the number of unnecessary follow-ups.”

The study is based on the population-based STHLM3-MRI study. All participants were tested with both PSA and Stockholm3 and followed for two years through national cancer registries, making it possible to identify cancer cases that were missed during the initial screening.

Missed fewer serious cases

During the follow-up, 443 men were diagnosed with clinically significant, or aggressive, prostate cancer. Stockholm3 missed significantly fewer serious cancer cases than PSA, while the proportion of men incorrectly classified as high risk was similar between the tests.

“These results point toward a potential change in how prostate cancer screening can be conducted. A more precise blood test could enable earlier detection of aggressive disease while reducing the number of unnecessary follow-up examinations and procedures,” Palsdottir said.

The researchers emphasize that longer-term follow-up is needed to fully assess the effects on mortality and long-term outcomes.

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