YuLin Zhen, Photography Editor

Prostate cancer is the second-leading cause of death among American men, killing one in 44. In the United States, 3.3 million men are survivors of prostate cancer, and the risk for developing the disease varies by race, ethnicity and age. 

A new study, co-led by Yale researchers and published in the Journal of the American Medical Association, or JAMA, found that high resolution micro-ultrasound, or microUS, is just as effective for guiding prostate cancer biopsies as MRI, or magnetic resonance imaging. 

The study was based on a randomized clinical trial with 678 participants. The researchers wanted to determine if high-resolution micro-ultrasonography-guided biopsy was better than MRI fusion-guided biopsy for detecting prostate cancer in a clinical setting. The study found that microUS was, in fact, a promising alternative to MRI.

“This is a game changer as MRI is a limited resource, with inadequate access globally. Even in the United States, only one-third of men have an MRI prior to biopsy, and this is decreased in the rural USA,” Dr. Adam Kinnaird, chair of prostate cancer research at the University of Alberta, told the News. “Micro-ultrasound can be used anywhere there is electricity and has the potential for reaching men at risk of prostate cancer worldwide.” 

Micro-ultrasound is an advanced ultrasound platform that utilizes 29 megahertz, or MHz, as opposed to the traditional ultrasound which performs at around seven to nine MHz. This makes the quality of the microUS more advanced, as it can assess glandular structure. 

Unlike MRI, which often requires multiple appointments and costly equipment, microUS enables clinicians to both scan and biopsy in a single session. This could streamline care and lower the barriers for patients, promoting equity in diagnosing prostate cancer in men. 

“Micro-ultrasound platform is less expensive than purchasing an MRI,” Dr. Joseph Renzulli, urologist at Yale, told the News. “The benefits of micro ultrasound are the ability to identify areas within the prostate that are concerning for potential prostate cancer and then targeting those areas with biopsy real time. This can all be done during one visit for the patient.”  

This shift from imaging-dependent referrals to point of care diagnostics led by urologists could lower costs dramatically in underserved and rural areas, shorten time to diagnosis in high-risk prostate cancer cases and reduce MRI bottlenecks in systems that are overburdened. 

The clinical trial took place across 20 centers in eight different countries, from December 2021 to September 2024, where each center did a noninferiority trial of biopsy-naive men. A noninferiority trial focuses on demonstrating that a new diagnostic tool, in this case microUS, is not worse than the current standard for detection, which in this case is MRI. This trial specifically worked with male patients who had never undergone a prostate biopsy but were being considered for one. The men were chosen based on elevated levels of prostate-specific antigen — a protein produced by the prostate — or abnormal rectal examination findings. 

The wider applicability of this technology is being investigated by other specialties. The learning curve for clinicians using microUS technology involves a combination of structured training and hands-on-experience. Clinicians must complete online training modules, become familiar with the PRIMUS scoring system for identification of ultrasound-visible lesions and work closely with company representatives to build proficiency. 

While early use is manageable with support, experts acknowledge that reaching a high level of diagnostic accuracy takes time. As a result, widespread implementation of this technology may be slowed by the need for comprehensive training, particularly in institutions without immediate access to training resources or experienced users. 

Implementing new technologies for tests that already have existing, effective procedures is challenging due to high costs, concerns with data privacy, cost of training staff and integrating with existing workflows to ensure the return on investment for the centers searching to change their technology. 

“I think in general for any new technology, there will be some resistance from providers who have an established workflow and are comfortable with their current approach. I do think that microUS technology does have the potential advantage of avoiding the need for MRI, which may save a significant amount of healthcare dollars and avoid a long and expensive exam for some patients,” Dr. Joseph Brito, urologist at Yale, told the News when asked about the challenges in implementing this technology. 

The American Urologic Association publishes practice guidelines that many urologists across the country use on a daily basis to inform their practice. The current guidelines discuss MRI as an option prior to prostate biopsy and recommend this targeted biopsy for anyone with a lesion identified on the MRI. There is no mention of microUS in the American Urologic Association, but it is a fairly new technology. 

JAMA is a peer-reviewed medical journal published 48 times a year by the American Medical Association.