Can pre-biopsy magnetic resonance imaging (MRI) have an impact in reducing unnecessary biopsies?
Retrospective Study in Sweden Shows Potential Benefits
In a new retrospective study, recently published in JAMA Network Open, researchers in Sweden compared a 2.4-year time period when pre-biopsy MRI use was low (from November 2, 2015 to February 28, 2018) and a subsequent 2.4-year time period (from March 1, 2018 to July 31, 2020) that showed a gradual increase of pre-biopsy MRI use in patients with suspected prostate cancer. The cohort was comprised of 23,802 men (mean age of 60.8) who had prostate-specific antigen (PSA) testing, according to the study. The researchers pointed out that pre-biopsy MRI has been recommended in national prostate cancer guidelines in Sweden since 2018.
Key Findings from the Study:
- The use of pre-biopsy MRI was associated with a 7 percent rate of negative biopsies, compared to 28 percent prior to adoption of pre-biopsy MRI.
- Diagnosis of Gleason score 6 cancers declined by 18 percent (6 percent vs. 24 percent) during the pre-biopsy MRI period of the study.
- Use of pre-biopsy MRI resulted in a 37 percent increase in the proportion of diagnosed Gleason score 7 to 10 cancers (86 percent vs. 49 percent) in comparison to the period prior to wider use of pre-biopsy MRI.
Lead study author David Robinson, Ph.D., who is affiliated with the Department of Urology at Highland Hospital in Eksjo, Sweden, and colleagues wrote, “In this population-based cohort study, the introduction of MRI was associated with a decrease in prostate biopsies, a decrease in negative biopsies, and a decrease in the detection of Gleason score 6 cancer, whereas the detection of Gleason score 7 or higher cancer increased.”
Further Analysis and Recommendations:
For men diagnosed with prostate cancer who had an initial PSA of 3 < 20 ng/mL, a sensitivity analysis revealed a 22 percent reduction in Gleason score 6 cancers detected via pre-biopsy MRI (16 percent vs. 38 percent).
Multivariable regression modeling revealed that higher use of pre-biopsy MRI led to fewer biopsies and a decreased risk of negative biopsies (odd ratio of 0.70) in comparison to the period prior to wider use of pre-biopsy MRI. Robinson and colleagues suggest that all men with PSAs between 3 and 20 ng/mL should undergo MRI before biopsy, but larger cohort studies are needed to validate these findings and explore the impact of pre-biopsy MRI on pertinent subgroup populations.
- The study period coincided with the peak of the COVID-19 pandemic, resulting in a decrease in PSA testing.
- Sweden’s National Prostate Cancer Register (NPCR) lacked clear separation between targeted and systematic biopsies.