MRI Cuts Prostate Cancer Screening Over-Diagnosis by Half

Using MRI to screen for prostate cancer can potentially cut over-diagnosis by half while detecting just as many clinically significant tumors.

According to research published July 9 in the New England Journal of Medicine, relying on MRI rather than prostate-specific antigen (PSA) to screen for cancer can reduce the number of unnecessary biopsies, saving patients pain and worry.

The study, called STHLM3MRI, was conducted by a group of investigators from Karolinska Institutet in Sweden, and results were presented during the European Association of Urology Conference.

“Our results from a large, randomized study show that modern methods for prostate cancer screening maintain the benefits of screening, while decreasing the harms substantially,” said study leader Tobias Nordström, associate professor of urology at Danderyd Hospital at Karolinska Institutet. “This addresses the greatest barrier to the introduction of nationwide screening.

To date, only one nation – Lithuania – has instituted a national prostate cancer screening program because too many problems exist. Using MRI over PSA could not only be good for patients, the team noted, but it could also generate financial benefits for healthcare systems. In particular, they said, the cost saving from fewer biopsies and less over-treatment could, in fact, balance out the additional costs associated with the modality.

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According to the team, MRI can pinpoint areas in the prostate that are suspicious for cancer, paving the way for more targeted biopsies and eliminating the need in men who have no visible lesions. As a result, the cancers detected are usually clinically significant.

To date, however, investigators have not examined the role MRI can play in prostate cancer screening. In an effort to determine its utility, Nordström’s team conducted the STHLM3MRI trial with 12,750 men eligible for prostate cancer screening between 2018 and 2021. Of the group, 1,532 had PSA levels above 3 ng per milliliter, and those individuals were randomly assigned to either a standard ultrasound biopsy protocol (603 patients) or the new MRI exam protocol (929 patients). Men with positive MRI results underwent standard and targeted biopsy.

Based on their evaluation, the team determined the MRI-targeted, combined biopsy method was statistically comparable to the standard biopsy protocol in identifying clinically significant cancers. It did, however, outperform standard biopsies in detecting clinically insignificant cancers.

Overall, the team said, for men with high PSA levels and a positive MRI exam, using the combined approach reduced the number of identified clinically insignificant tumors by 64 percent over the standard biopsy method – and it did so without performance degradation with clinically significant cancers.

These results – a reduction in unnecessary biopsies and diagnoses of clinically insignificant cancers – show that it is possible to overcome the roadblocks that exist to prostate cancer screening programs.

“We are finally able to show that men can also reduce their risk of malignant cancer through nationwide prostate-cancer screening that utilizes modern methods,” Nordström said.