Diagnostic accuracy of abbreviated biparametric MRI for prostate cancer screening: a prospective feasibility study (ReIMAGINE study).

OBJECTIVES

To evaluate the diagnostic accuracy and imaging findings of an abbreviated biparametric MRI (bpMRI) protocol for prostate cancer (PCa) screening.

MATERIALS AND METHODS

In this single-centre, prospective study, men aged 50-75 years were randomly selected for invitation to screening through participating general practices. Participants underwent screening with abbreviated bpMRI (axial T2-weighted and b2000 diffusion-weighted sequences) and PSA testing between October 2019 and December 2020. Screening MRIs were independently reported by two radiologists as either positive or negative by screening criteria, with a third radiologist if there was disagreement. Positive MRI or raised PSA density (PSAd) (≥ 0.12 ng/mL) triggered standard-of-care NHS PCa assessment. Outcomes of the NHS assessment were collated as a composite reference standard and included multiparametric MRI ± biopsy, and a 2-year healthcare record follow-up. Diagnostic accuracy was evaluated using positive predictive value (PPV).

RESULTS

Among 303 men who completed screening (median age 62 years [IQR 56, 68]), 16% (48/303) had a positive screening MRI, and an additional 5% (16/303) had raised PSAd alone. Of 61 men referred to secondary care, 48% (29/61) had clinically significant PCa, with 2 (3%, 2/61) additional diagnoses during 2-year follow-up. Of 31 men with clinically significant PCa, 87% (27/31) had a positive screening MRI and 42% (13/31) had raised PSAd. The PPV of the screening MRI was 59% (27/46, 95% CI: 44, 72).

CONCLUSION

Abbreviated bpMRI may have value in PCa screening independently of PSA testing. However, prospective multicentre evaluation is needed to assess the feasibility and cost-effectiveness of MRI-based screening at a national level.

KEY POINTS

Question MRI may reduce over- and under-diagnosis from prostate-specific antigen (PSA) testing in PCa screening, but its use is limited by long scan times, cost, and availability. Findings Abbreviated bpMRI identified more men with clinically significant cancer than PSAd (≥ 0.12 ng/mL), with a PPV of 59% (95% CI: 44, 72). Clinical relevance Prostate MRI may improve cancer detection independently of PSA testing, with abbreviated protocols enhancing feasibility and scalability. While MRI may offer an opportunity for early diagnosis, further prospective, multicentre evaluation is needed to explore its potential role in screening settings.