In a Canadian phase III trial reported in JAMA Oncology, Klotz et al found that multiparametric magnetic resonance imaging (MRI) with targeted biopsy was noninferior to systematic 12-core transrectal ultrasonography biopsy in detecting International Society of Urological Pathology grade group 2 (GG2) or greater prostate cancer in biopsy-naive men with clinical suspicion for prostate cancer.
In the multicenter trial, 453 patients with clinical suspicion for prostate cancer were randomly assigned between April 2017 and November 2019 to undergo MRI with targeted biopsy (n = 226) or transrectal ultrasonography biopsy (n = 227). In the MRI with targeted biopsy group, biopsy was performed only if a lesion with a Prostate Imaging Reporting and Data System (PI-RADS v2.0) score of 3 or greater was identified on MRI. Clinical suspicion was defined as a 5% or greater chance of GG2 or greater prostate cancer using the Prostate Cancer Prevention Trial Risk Calculator version 2. Patients had to have prostate-specific antigen levels of ≤ 20 ng/mL and no contraindication for MRI. The primary outcome measure was the proportion of men with a diagnosis of GG2 or greater cancer in the intention-to-treat population with a noninferiority margin of –5%.
MRI followed by selected targeted biopsy is noninferior to initial systematic biopsy in men at risk for prostate cancer in detecting GG2 or greater cancers.— Klotz et al
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Cancers of GG2 or greater were identified in 79 (34.8%) of patients in the MRI with targeted biopsy group vs 67 (29.7%) in the transrectal ultrasonography biopsy group (absolute difference = 5%, 97.5% 1-sided confidence interval [CI] = −3.4% to ∞), with MRI with targeted biopsy meeting the noninferiority criterion. A test for superiority showed no significant difference between groups (P = .27).
Among 219 vs 202 patients in the per-protocol population, GG2 or greater disease was identified in 36.1% vs 33.2% (absolute difference = 2.9%, 95% 1-sided CI = –6.2% to 12.0%), with a test for superiority not being significant (P = .54).
Among 221 patients who underwent MRI, a lesion with PI-RADS score of 3 or greater was found in 138 (62.4%), with lesions with scores of 3, 4, and 5 found in 12.1%, 38.1%, and 14.0%, respectively. A total of 83 (37.6%) had a negative MRI result and avoided biopsy.
There were fewer diagnoses of GG1 cancer in the MRI with targeted biopsy group (10.1% vs 21.7%, absolute difference = –11.6%, 95% CI = −18.2% to −4.9%, P < .001).
Adverse events occurred in 40% vs 64% of patients, with grade ≥ 3 events occurring in 3.5% vs 4.4%. Among patients undergoing biopsy, 37% vs 53% reported that undergoing another biopsy would be a problem.
The investigators concluded, “MRI followed by selected targeted biopsy is noninferior to initial systematic biopsy in men at risk for prostate cancer in detecting GG2 or greater cancers.”
Laurence Klotz, CM, MD, of Sunnybrook Health Sciences Centre, Toronto, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was funded by grants from the Ontario Institute of Cancer and Prostate Cancer Canada. For full disclosures of the study authors, visit jamanetwork.com.