In men requiring repeat biopsy for suspicion of prostate cancer, multiparametric MRI (mpMRI) overlooks few clinically significant prostate lesions, Joseph M. Norris, PhD, of the University College London in the United Kingdom reported at the 36th annual European Association of Urology virtual congress.
Dr Norris and colleagues performed a secondary analysis of the PICTURE (Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation) trial. A total of 195 men underwent mpMRI, followed by 5 mm transperineal template mapping biopsy (a repeat biopsy). Nonsuspicious mpMRI findings were defined as Likert 1 or 2.
Results showed that mpMRI missed 2.9% of clinically significant prostate cancers according to definition 1 (Gleason score 4+3 or higher cancer of any amount or maximum cancer core length [MCCL] of 6 mm or longer of any grade). The proportion of missed cancers increased to 6.5% using definition 2 (Gleason score 3+4 or higher or MCCL of 4 mm or longer). Further, mpMRI missed 4.8% of cancers with any Gleason score of 7 or higher, and 9.3% of cases with positive cancer cores.
The most clinically significant prostate cancers according to definition 1 that were missed by mpMRI had a significantly lower overall Gleason score and maximum Gleason grade than cancers detected by mpMRI. Prostate cancers missed by mpMRI also had significantly shorter MCCL than cancers detected by mpMRI using any of the 4 definitions.
When the investigators incorporated a PSA density threshold of 0.15 ng/mL/mL as an additional criterion, no significant prostate cancers remained undetected by definition 1 and 0.58% remained undetected by definition 2.
“MRI misses very few cancers in men with previous prostate biopsies,” Dr Norris said. “Furthermore, when MRI overlooks a cancer, it is likely that this cancer is of low clinical significance, as defined by various Gleason grading and tumor volume definitions. This work adds to the growing body of MRI research, and reiterates and reinforces the primacy that mpMRI now holds in the diagnostic paradigm for prostate cancer.”
Norris JM, Simmons LAM, Kanthabalan A, et al. Which prostate cancers are undetected by multiparametric magnetic resonance imaging in men with previous prostate biopsy? An analysis from the PICTURE study. Presented at the EAU 2021 virtual conference, July 8-12, 2021. Abstract P0903.