MRI-Targeted vs Standard Biopsy in Prostate Cancer Diagnosis
In the international PRECISION trial reported in The New England Journal of Medicine, Kasivisvanathan et al found that magnetic resonance imaging (MRI)-targeted biopsy resulted in a significantly higher rate of diagnosis of clinically significant prostate cancer and a lower rate of diagnosis of clinically insignificant disease compared with standard transrectal ultrasonography–guided biopsy in men with clinically suspected prostate cancer.
Study Details
In the trial, 500 men with elevated prostate-specific antigen (PSA) level, abnormal digital rectal exam, or both who had not undergone prior biopsy from 23 sites in 11 countries in Europe and North America were randomized between February 2016 and August 2017 to receive multiparametric MRI with or without targeted biopsy (n = 252) or standard transrectal ultrasonography-guided biopsy (n = 248). Patients had to have PSA level ≤ 20 ng/mL and results on digital rectal exam not suggestive of extracapsular disease.
Patients in the MRI-targeted biopsy group underwent targeted biopsy (without standard biopsy cores) only if MRI was suggestive of prostate cancer (Prostate Imaging–Reporting and Data System, version 2 [PI-RADS v2] score of > 2); those without such findings (PI-RADS score ≤ 2) were not offered biopsy. Standard biopsy was a 10- to 12-core biopsy.
The primary outcome measure was the proportion of men who received a diagnosis of clinically significant cancer on intention-to-treat analysis. Noninferiority was established if the lower boundary of the 95% confidence interval (CI) for the difference in rates of detection of clinically significant cancer in the MRI-targeted biopsy group vs the standard biopsy group was greater than –5%. Superiority was claimed if the lower boundary was greater than zero. Secondary outcomes included the proportion of men who received a diagnosis of clinically insignificant cancer.
Detection of Clinically Significant Cancer
In the MRI-targeted biopsy group, 71 (28%) of 252 men had MRI results not suggestive of prostate cancer and did not undergo biopsy. Clinically significant cancer was detected in 95 men (38%) in the MRI-targeted biopsy group vs 64 (26%) of 248 in the standard biopsy group. The adjusted difference was 12%, with a 95% CI of 4%–20% (P = .005 for superiority), meeting the criteria for noninferiority and superiority. A diagnosis of clinically insignificant prostate cancer was received by 23 men (9%) in the MRI-targeted biopsy group vs 55 (22%) of those in the standard biopsy group (adjusted difference = –13%, 95% CI = –19% to –7%, P < .001).
In patients with cancer, the mean maximum cancer core length was 7.8 mm in the MRI-targeted biopsy group vs 6.5 mm in the standard biopsy group (adjusted mean difference = 1.0 mm, P = .053). In total, 422 (44%) of 967 cores were positive for cancer in the MRI-targeted biopsy group vs 515 (18%) of 2,788 in the standard biopsy group. Among patients with positive MRI findings, the proportions with clinically significant cancer were 83%, 60%, and 12% among those with PI-RADS scores of 5, 4, and 3, respectively.
Adverse Events
No difference between groups was observed in health-related quality of life at 24 hours or 30 days after intervention using the EuroQol-5 Dimension Self-Report Questionnaire. Immediate postintervention discomfort and pain were similar in the two groups. Patient-reported complications at 30 days were less common in the MRI-targeted biopsy group, including blood in the urine (30% vs 63%), blood in the semen (32% vs 60%), pain at the procedure site (13% vs 23%), rectal bleeding (14% vs 22%), and erectile dysfunction (11% vs 16%); these differences reflect a lower percentage of men undergoing biopsy and acquisition of fewer biopsy cores in the MRI-targeted biopsy group. Serious adverse events occurred in 2% of patients in each group.
The investigators concluded, “The use of risk assessment with MRI before biopsy and MRI-targeted biopsy was superior to standard transrectal ultrasonography–guided biopsy in men at clinical risk for prostate cancer who had not undergone biopsy previously.”
The study was funded by the National Institute for Health Research and the European Association of Urology Research Foundation.
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