Is MRI Overutilized in Prostate Cancer Imaging?

Findings from a recent study suggest that magnetic resonance imaging (MRI) may be overutilized in subsequent biennial screening for men with elevated prostate-specific antigen (PSA) levels and prior negative screening for prostate cancer.

For the study, a secondary analysis of the STHLM3-MRI randomized trial recently published in JAMA Network Open, researchers assessed the use of repeat prostate cancer (PCa) screening in 1,500 men (median age of 67) two to three years after prior negative screening results with PSA levels 1.5 ng/mL or greater. The study authors noted that 617 of 667 men with PSA levels at 3 ng/mL or greater had MRI exams.

The researchers found that 533 of the men with elevated PSAs (79.9 percent) had no suspicious findings on MRI for PCa. The study authors noted equivocal findings on MRI (PI-RADS 3 scores) for 51 patients (7.6 percent) while 33 patients (4.9 percent) had PI-RADS 4 or PI-RADS 5 scores for at least one suspicious lesion.

Out of 10 patients who had a PI-RADS 5 lesion in the second round of PCa screening, the researchers noted that none of the patients had an MRI.

“The high proportion of negative MRI results is striking, and it would lead to an overutilization of MRI resources if used for biannual prostate cancer screening in combination with PSA levels of 3 ng/mL or greater as the cutoff for a single biomarker strategy for further workup. This supports the use of reflex testing in men with moderately elevated PSA,” wrote lead study author Tobias Nordstrom, M.D., Ph.D., who is affiliated with the Department of Medical Epidemiology and Biostatistics and the Department of Clinical Sciences at the Karolinska Institute in Stockholm, Sweden, and colleagues.

The researchers pointed out that prior negative results on MRI in the initial PCa screening round led to similar results for a significant majority of patients at subsequent MRI screening two to three years later.

“The proportion of MRI scans with lesions suspicious for cancer (PI-RADS score ≥4) was low among men with a previous negative MRI result (10 of 383 [2.6%]). No lesions with PI-RADS scores of 4 or 5 were found among men with a previous positive MRI result followed by benign findings at biopsy,” added Nordstrom and colleagues.

(Editor’s note: For related content, see “Can Combination of mpMRI and Extracellular Vesicle-Based Biomarkers Enhance csPCa Detection?,” “What Post-Void MRIs May Reveal About Midline Radiotracer Activity on PSMA PET/CT” and “Emerging Predictive Model with mpMRI Findings May Reduce Up to 43 Percent of Unnecessary Systematic Prostate Biopsies.”)

In regard to study limitations, the researchers noted the lack of long-term mortality outcomes and pointed out the cohort was limited to men who had follow-up screening two to three years after having PSA levels of 1.5 ng/mL or greater at an initial screening.