In men with clinical suspicion of prostate cancer (elevated PSA or abnormal DRE), multiparametric magnetic resonance imaging of the prostate may be useful as a triage test to reduce the number of unnecessary biopsies while enhancing the detection of clinically significant prostate cancer (CS-PCa). The recent paper from the PRECISION study group reported that, in biopsy-naïve men, CS-PCa detection (any core with Gleason score ≥3+4) was significantly higher and the risk of cancer detection was significantly lower in men undergoing MRI-targeted biopsy when compared to the standard transrectal ultrasound-guided biopsy (N Engl J Med March 18, 2018 [Epub ahead of print]).
The authors identified 500 patients with elevated PSA and/or abnormal DRE and randomized 252 men to the MRI-targeted biopsy group and 248 to the standard-biopsy group. Of the 252 men in the MRI-targeted biopsy group, 181 (72%) with suspicious lesions (defined as PIRADS 3-5) underwent biopsy of the target lesions only while 71 men (28%) with a normal MRI (PIRADS 1 or 2) did not undergo a biopsy at all. While the standard-biopsy group had systematic biopsy with an average of 12 cores, the MRI targeted biopsy obtained an average of four cores per patient.
Ninety-five men (38%) in the MRI-targeted biopsy group had CS-PCa compared to 64 (26%) in the standard-biopsy group (p=.005). Fewer men were diagnosed with low-risk prostate cancer in the MRI-targeted biopsy group (23 men, 9%) than in the standard-biopsy group (55 men, 22%, p<.001).
In men with the MRI demonstrating a targetable lesion, 51 of 175 (29%) had a PI-RADS score 3, 70 (40%) had a score of 4, and 54 (31%) had a score of 5. CS-PCa rate for PIRADS score 3, 4, and 5 was 12%, 60%, and 83%, respectively. Conversely, the negative biopsy rate for PIRADS score 3, 4, and 5 was 67%, 31%, and 6%, respectively.
Percentage of biopsy cores with cancer was significantly higher in the MRI-targeted biopsy group (422 of 967 cores, 44%) than in the standard-biopsy group (515 of 2,788 cores, 18%); ie, much fewer cores were needed to detect a higher rate of CS-PCa. Post-biopsy complications were less common in the MRI-targeted group than the standard-biopsy group, including hematuria (30% vs. 63%), hematospermia (32% vs. 60%), pain (13% vs. 23%), rectal bleeding (14% vs. 22%), and erectile dysfunction (11% vs. 16%), respectively. This difference in the patient-reported 30-day complication rate is explained by the fact that fewer men in the MRI-targeted group needed a biopsy and only a few cores were obtained per biopsy session.