Here's a study:
Population-based prostate cancer screening with Magnetic Resonance or Ultrasound Imaging: The IP1-PROSTAGRAM study (2021)
"
Abstract
Importance: Screening for prostate cancer using PSA-testing can lead to problems of under- and over-diagnosis. A short, non-contrast MRI or transrectal ultrasound might overcome these limitations.
Objective: To compare the performance of PSA, MRI and ultrasound as screening tests for prostate cancer.
Design, Setting and Participants: This prospective, population-based, blinded cohort study was conducted at seven primary care practices and two imaging centres in the UK. 2034 community based men aged 50-69 years invited for prostate cancer screening and 408 were consented. Interventions: All participants underwent screening with a PSA test, MRI (T2-weighted and diffusion) and ultrasound (b-mode and shearwave elastography).-The tests were independently interpreted without knowledge of other results. Both imaging tests were reported on a validated 5-point scale of suspicion. If any test was screen-positive, a systematic 12-core biopsy was performed. Additional image-fusion targeted biopsies were taken if the MRI or ultrasound was positive.
Main Outcomes and Measures: The proportion of men with screen-positive MRI or ultrasound (defined as either score 3-5 or 4-5) or screen-positive PSA (defined as PSA≥3g/L). Key secondary outcomes were the number of clinically-significant and clinically-insignificant cancers detected if each test was used exclusively. Clinically-significant cancer was defined as any Gleason score≥3+4.
Results: The proportion with a screen-positive MRI (score 3-5) was higher than the proportion with a screen-positive PSA (72/406, 17.7%[95%CI 14.3-21.8] vs. 40/406,9.9%[95%CI 7.3-13.2]; p<0.001). The proportion with a screen-positive ultrasound (score 3-5) was also higher than PSA (96/405, 23.7% [95%CI 19.8-28.1];p<0.001). For an imaging threshold of score 4-5, the proportion with a screen-positive MRI was similar to PSA (43/406, 10.6%[95%CI 7.9-13.2];p=0.71), as was the proportion with a screen-positive ultrasound (52/405, 12.8%[95%CI 9.9-16.5];p=0.15). PSA(≥3ng/ml) detected 7 clinically-significant cancers.-MRI (score 3-5) detected 14 and MRI (score 4-5) detected 11. Ultrasound (score 3-5) detected 9 and ultrasound (score 4-5) detected 4. Clinically-insignificant cancers were diagnosed by PSA in 6 cases, by MRI (score 3-5) in 7, MRI (score 4-5) in 5, ultrasound101 (score 3-5) in 13 and ultrasound (score 4-5) in 7.
Conclusions and Relevance: When screening the general population for prostate cancer, MRI using a score of 4 or 5 to define a screen-positive test compared to PSA alone at ≥3ng/ml, might lead to more men diagnosed with clinically-significant cancer, without increasing the number of men recommended to have a biopsy or over-diagnosed with clinically-insignificant cancer. There was no evidence that ultrasound would have better performance compared to PSA alone."
___________________________
[Emphasis mine] Of course what we don't want to do is just pick up more G3 (6+6) disease. From the Abstract, I'm not sure the MRIs did any better than PSA for high-grade disease. The promise of "liquid biopsies" (on blood or urine) is that they will be specific for clinically significant disease (G7 and up). As with many new ideas, we have to see how these MRIs pan out (notice the "might lead to" in the highlighted sentence).
Djin