Microultrasonography positioned as alternative to MRI for image-guided prostate biopsy

Microultrasonography-guided biopsy demonstrated noninferiority to MRI/conventional ultrasonography fusion-guided biopsy in the detection of clinically significant prostate cancer in biopsy-naïve men, according to data from the randomized OPTIMUM trial (NCT05220501).¹

According to the authors, these findings suggest that microultrasonography-guided biopsy may provide a viable alternative to MRI for image-guided prostate biopsy.

The results were presented at the European Multidisciplinary Congress on Urological Cancers (EMUC) in Prague. The findings were also previously presented at the European Association of Urology (EAU)’s Annual Meeting in March 2025 and concurrently published in JAMA.¹

“These results are a game-changer for urologists and patients, as we now have an in-office diagnostic tool proven non-inferior to MRI that is easy-to-use, affordable, and speeds the diagnosis process for patients,” said Laurence Klotz, MD, FRCSC, professor in the department of surgery at the University of Toronto and chair of prostate cancer research at Sunnybrook Health Sciences Center, in a news release on the findings.² “I believe the technology has the potential to improve standard of care and reduce care disparities, especially for those with limited access to MRI.”

In total, the open-label study enrolled 802 men with clinical suspicion of prostate cancer across 20 international clinical trial sites. Patients were randomly assigned to receive microultrasonography (n = 137) via the ExactVu micro-ultrasound platform, MRI/conventional ultrasonography (n = 402), or microultrasonography/MRI (n = 263). Baseline characteristics were well-balanced between all 3 arms. Overall, 88% of patients in the microultrasonography group, 82% of patients in the MRI/conventional ultrasonography group, and 86% of patients in the microultrasonography/MRI group underwent prostate biopsy.

Across all cohorts, clinically significant prostate cancer (grade group 2 or higher) was detected in 47.1% of patients (n = 57) in the microultrasonography group, 42.6% of patients (n = 141) in the MRI/conventional ultrasonography group, and 46.9% of patients (n = 106) in the microultrasonography/MRI group.

The study met its primary end point by showing that microultrasonography (both the microultrasonography group and the microultrasonography/MRI group) was non-inferior to MRI fusion-guided biopsy (46% vs 43%; difference, 3.52%; 95% CI, −3.95% to 10.92%; noninferiority P < .001) in the detection of clinically significant prostate cancer.

The trial also met its secondary end point of detection of clinically significant prostate cancer by combined microultrasonography/MRI-guided biopsy compared with MRI/conventional ultrasonography-guided biopsy. Overall, grade group 2 or higher prostate cancer was detected in 47% of patients (n = 106) who underwent microultrasonography/MRI-guided biopsy vs 43% of patients (n = 141) who underwent MRI/conventional ultrasonography-guided biopsy (difference, 4.29%; 95% CI, −4.06% to 12.63%; noninferiority P < .001).

There was no significant difference between the groups in the detection of grade group 1 cancer. These rates were 11.6% in the microultrasonography group, 15.4% in the MRI/conventional ultrasonography group, and 17.3% in the microultrasonography/MRI group (1-way analysis of variance [ANOVA], P = .3).

Further, there were no significant differences between the arms in the rates of Gleason grade group 2 or higher cancer diagnosed by targeted biopsy only. Specifically, the targeted biopsy-only detection rate was 38.0% in the microultrasonography group, 34.1% in the MRI/conventional ultrasonography group, and 40.3% in the microultrasonography/MRI group.

“The JAMA publication and EAU presentation of the OPTIMUM trial, and its subsequent presentation at EMUC 2025, are major validations for micro-ultrasound technology and a defining milestone for the company,” concluded Randy AuCoin, president and CEO of Exact Imaging, in the news release.² “The results underscore the transformative potential of micro-ultrasound to make high-quality prostate imaging available to every patient, regardless of access to MRI.”

REFERENCES
1. Kinnaird A, Luger F, Cash H, et al. Microultrasonography-guided vs MRI-guided biopsy for prostate cancer diagnosis: The OPTIMUM randomized clinical trial. JAMA. 2025 May 20;333(19):1679-1687. doi:10.1001/jama.2025.3579

2. Micro-ultrasound proven non-inferior to MRI for prostate cancer diagnosis in OPTIMUM randomized trial. News release. Exact Imaging. November 19, 2025. Accessed November 19, 2025. https://www.businesswire.com/news/home/20251119703366/en/Micro-ultrasound-Proven-Non-Inferior-to-MRI-for-Prostate-Cancer-Diagnosis-in-OPTIMUM-Randomized-Trial