MRI-targeted biopsy shows value in prostate cancer

By Erik L. Ridley, staff writer

February 5, 2021 -- Multiparametric MRI-targeted biopsy for clinically significant prostate cancer can yield detection rates similar to systematic transrectal ultrasound-guided (TRUS) biopsy, while potentially enabling over one-third of prostate biopsies to be avoided, according to research published online February 4 in JAMA Oncology.

In a multicenter, prospective, and randomized phase III study called PRostate Evaluation for Clinically Important Disease: MRI vs. Standard Evaluation Procedures (PRECISE), a team of researchers from Canada found that providing targeted biopsies after a positive multiparametric MRI scan was noninferior to systematic TRUS biopsies for detecting prostate cancers with an International Society of Urological Pathology grade group (GG) of 2 or higher.

What's more, the MRI-first strategy yielded a nearly 40% decrease in the biopsy rate and a substantial reduction in the rate of biopsy findings of GG1 cancer or no cancer, as well as fewer adverse events.

"My colleagues and I are thrilled about these results that show, without a doubt, that imaging and targeted biopsies are the future of prostate cancer diagnosis," said first author Dr. Laurence Klotz of Sunnybrook Health Sciences Center in Toronto in a statement. "We can catch more of the cancers we should be treating, avoid unnecessary treatment at the same time, and improve the quality of life for our patients."

Although MRI with targeted biopsy offers an appealing alternative to systematic 12-core TRUS-guided biopsy, the method hasn't yet been widely adopted, according to the researchers. To assess whether MRI-targeted biopsy was noninferior to TRUS biopsy, they enrolled 453 patients with a clinical suspicion of prostate cancer at five Canadian academic health sciences centers between April 2017 and November 2019. Of these, 226 men were assigned to the systematic TRUS biopsy arm and 227 were allocated to the MRI arm.

The researchers reported that 83 (37%) of the 221 men who ultimately received an MRI had negative findings (PI-RADS score ≤ 2) and avoided biopsy.

Performance of MRI-guided biopsy for prostate cancer
  Systematic TRUS-guided biopsy study arm MRI-targeted biopsy study arm
Detection of cancers ≥ GG2 67 of 225 patients (29.7%) 79 of 227 patients (34.8%)
Percentage of patients who received biopsies that detected cancers ≥ GG2 33.2% 58.1%
GG1 cancers detected 49 (21.7%) 23 (10.1%)
Mean number of biopsy cores per patient 11.4 6.3
Mean number of positive biopsy cores per patient 4.4 4.4

The difference in detection of cancers ≥ GG2 was not statistically significant (p = 0.23). In other results, the MRI study arm also experienced 25% fewer adverse events such as prostatitis, hematuria, hematospermia, and incontinence.

Given its noninferiority for detecting clinically significant prostate cancer along with its other benefits, the strategy of MRI before biopsy appears to be superior, according to the researchers.

However, in an accompanying invited commentary, Dr. Olivier Rouvière, PhD, of Hospital édouard Herriot in Lyon, France, said that the ideal diagnostic pathway for prostate cancer in biopsy-naive patients is unlikely to be based only on MRI as a triage test, or having every patient receive MRI followed by a combination of systematic and targeted biopsy.

"Most likely, MRI findings will be used in conjunction with other biomarkers such as PSA density to select, among the patients with positive MRI findings, those who need targeted biopsy (and those who may safely avoid it), and among the patients with negative MRI findings, those who may still deserve systematic biopsy," he wrote.

In addition, quality assurance will need to be strictly implemented at the institution level for monitoring the interpretation of the MRI exams and the execution of both of the targeted and systematic biopsies, according to Rouvière.

Copyright © 2021

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