CATEGORY: MEN’S HEALTH
In a randomized trial of 13,153 Swedish men aged 50 to 60, adding an MRI scan to prostate cancer screening and skipping the biopsy when that scan was clear was followed by 57% fewer diagnoses of harmless prostate cancer, with no detectable loss in finding the dangerous kind.1 Fewer diagnoses is the benefit here, which takes a moment to see. Prostate screening’s central problem is overdiagnosis: finding slow-growing cancers that would never have caused symptoms, then treating them with surgery or radiation that can leave men incontinent or unable to have erections.
Twelve-Sample Biopsy Versus Skipping Biopsy After Clear MRI
Men were invited from the population register for a PSA blood test, which measures a protein made by the prostate. Anyone with a raised result had an MRI scan. At that point they were randomly assigned to one of two paths: the standard approach, a systematic biopsy taking twelve tissue samples plus targeted samples of anything suspicious on the scan, or an MRI-guided approach in which men whose scan showed nothing suspicious had no biopsy at all. Men were re-invited for further rounds of screening at two, four or eight years depending on their PSA level, so this covers repeated screening rather than a single test. Every cancer was classified by a pathologist examining the tissue, which is how the harmless and the dangerous were told apart.
Cancer Found in 2.8% Versus 4.5% of Men
Prostate cancer of any kind was found in 2.8% of the MRI-guided group and 4.5% of the systematic-biopsy group—about 1.7 fewer men diagnosed per 100 screened. In counts, 185 men in the MRI-guided group and 298 in the systematic-biopsy group were diagnosed.1 Diagnoses of clinically insignificant cancer, the grade least likely to ever cause harm, were 57% lower, with a range of 43% to 68%. Reducing these harmless diagnoses was the trial’s prespecified main outcome, while finding the dangerous kind was a secondary one.1 Detection of clinically significant cancer showed no significant difference between the two groups.
Half as Many in Round One, a Quarter Later
In the first round of screening the MRI-guided approach produced about half as many harmless diagnoses. In later rounds it produced about a quarter as many. Serious complications were rare in both groups: five in total across more than 13,000 men.
Median Follow-Up 3.9 Years, Too Short for Deaths
Median follow-up was 3.9 years. That is long enough to count diagnoses but not deaths, so this trial does not show that either approach saves more lives; the mortality analysis is years away. Cancers classed as advanced or high-risk were fewer in the MRI-guided group, 15 against 23, but the numbers are too small to draw a conclusion from. The men were Swedish, aged 50 to 60, and screened in a system with high-quality MRI and experienced radiologists—the scan quality is the assumption the whole approach rests on. Funding came from Swedish cancer charities and public research bodies, not from industry.
STHLM3-MRI Found 15% Less Aggressive Cancer Detected
A separate analysis of another Swedish screening trial, STHLM3-MRI, found the trade-off less clean: among men whose scan flagged a suspicious area, dropping the twelve standard tissue samples and relying on targeted ones alone lowered detection of aggressive cancer by about 15%, and for each harmless cancer avoided roughly four aggressive ones went unfound.2 How much a scan-led approach spares men may depend on which biopsies are skipped.
Key Takeaways
- Among 13,153 men randomly assigned, an MRI-first approach cut diagnoses of harmless prostate cancer by 57% while finding a similar number of the cancers that matter.
- Avoiding a diagnosis is the benefit: harmless prostate cancers, once found, are often treated with surgery or radiation carrying lasting side effects.
- The trial counted diagnoses, not deaths—after 3.9 years it cannot say whether either approach saves more lives.
References
- Hugosson J, Godtman RA, Wallström J, et al. Results after Four Years of Screening for Prostate Cancer with PSA and MRI. New England Journal of Medicine. 2024;391(12):1083–1095. link
- Chandra Engel J, Eklund M, Jäderling F, et al. Diagnostic effects of omitting systematic biopsies in prostate cancer screening. European Urology Oncology. 2025;8(2):435–443. link.