(UroToday.com) The 2024 European Association of Urology (EAU) annual meeting featured a game changing session for guideline changes in screening and diagnosis for prostate cancer, and a presentation by Dr. Veeru Kasivisvanathan discussing results from the PRIME study assessing the comparison of biparametric and multiparametric MRI for prostate cancer detection.
Dr. Kasivisvanathan notes that a number of high-profile studies, including PRECISION,1 have led to international guidelines and panels recommending multiparametric MRI for clinical suspicion of prostate cancer. So, why consider biparametric MRI? Only 62% of men who need a prostate MRI in the UK get one, thus the demand is much higher than the supply. Multiparametric MRIs have several phases, including diffusion-weighted, T2-weighted, and contrast enhanced, which is time consuming (30-40 minutes), requires an injection, and requires a doctor:
Thus, the proposed benefits of biparametric MRI are that it (i) avoids cannulation, (ii) avoids the need for a doctor, (iii) avoids gadolinium contrast, and (iv) is a shorter, cheaper scan. Limitations of previous studies assessing bp-MRI are as follows:
- Small or single center or retrospective
- Only use PI-RADS v2.1
- No strict blinding of the radiologist
- Biopsies performed only on mpMRI information
- No MRI quality control
Thus, PRIME is a prospective, international, within-patient, multicenter, level 1 evidence trial, with an aim to assess whether bpMRI is non-inferior to mpMRI in detecting clinically significant prostate cancer. The trial schema for PRIME is as follows:
This is a true international trial encompassing 5 continents, 22 sites, and 12 countries. There were 1,406 men considered for the trial, of which 555 were enrolled and underwent MRI, with 490 included in the primary analysis. The baseline characteristics are as follows:
The proportion of scans scored >= 3 on MRI leading to a biopsy indication included 56% for bpMRI and 57% for mpMRI. Dynamic contrast enhancement identified new areas of suspicion in 31/490 (6.3%) of cases, including 21 (4.3%) new areas not see on bpMRI, and 10 (2.0%) of cases having existing lesions that were much larger on mpMRI. Clinically significant prostate cancer was detected in 29.2% of patients from mpMRI and 28.8% of patients from bpMRI (p = 0.50), with a difference of 0.4% (95% CI -0.4 to 1.2) above the non-inferiority margin of -5%:
Thus, biparametric MRI is non-inferior to multiparametric MRI for clinical significant prostate cancer diagnosis, with no increase in number of men with a biopsy indication based on bpMRI. Additionally, the diagnostic test performance characteristics were very comparable between the two MRI techniques:
Clinically insignificant cancer (Gleason 3+3) was detected in 10.0% from mpMRI and 9.6% from bpMRI. With regards to the impact of treatment decisions, dynamic contrast enhancement made a difference to treatment eligibility in 20/469 (4%) of cases and made a difference in treatment planning in 14/469 (3%) of cases:
Thus, Dr. Kasivisvanathan states that dynamic contrast enhancement had a minimal impact on treatment decisions or how treatments are delivered. Overall, 70% of scans were of optimal PI-QUAL 5 quality, with the reason for 30% being <= PI-QUAL 4 being issues with T2W or DWI (21%) or issues with DCE (9%). Moreover, 80% of issues were patient factors rather than technical factors.
Dr. Kasivisvanathan concluded his presentation discussing results from the PRIME study with the following summary statements and conclusions:
- Biparametric MRI without dynamic contrast enhancement, in the presence of good quality of scans, results in:
- No difference in clinically significant or insignificant cancer detection
- No increase in biopsies
- No difference in specificity or false positives
- Minor differences in treatment eligibility decisions and treatment planning
- Biparametric MRI without dynamic contrast enhancement should become the new standard of care for prostate cancer diagnosis in men with suspected prostate cancer, providing image quality is good
- This will increase accessibility, cost-effectiveness, and adoption of prostate MRI
- This will help us achieve our goal of ensuring every man who needs an MRI scan will be able to get one
Presented by: Veeru Kasivisvanathan, MBBS, Associate Professor, University College London, London, UK
Written by: Zachary Klaassen, MD, MSc - Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, WellStar MCG Health, @zklaassen_md on Twitter during the 2024 European Association of Urology (EAU) annual congress, Paris, France, April 5th - April 8th, 2024
References:
- Kasivisvanathan V, Rannikko AS, Borghi M, et al. MRI-targeted or standard biopsy for prostate cancer diagnosis. N Engl J Med 2018;378(19):1767-1777.