High-intensity focused ultrasound (HIFU) for prostate cancer treatment

Prostate cancer is the most common form of cancer among men. In 2020 alone, the American Cancer Society estimates that 191,930 men in the United States will be diagnosed with the disease. Although survival rates are high (estimated at 98% ten years after treatment), prostate cancer remains the second leading cause of cancer death for American men. Treatment of the disease typically consists of radiation therapy or surgery. However, a recently published study in The Journal of Urology revealed that high-intensity focused ultrasound (HIFU) can be used as a treatment for localized prostate cancer.

HIFU uses a transducer with much higher energy than those used for diagnostic imaging and focuses sound waves on the target area. These waves generate heat at a single point within the body to destroy the target. Within just 20 seconds, the transducer can heat the issue up to 150 °F. The physician may repeat this process multiple times until the lesion or tumor is destroyed.

The research team from the University of Southern California said the HIFU treatment would give patients the ability to avoid more invasive treatment options, such as surgery or radiation. Both options are known to come with a whole host of side effects, such as risk of infection during surgery or fatigue after radiation therapy. HIFU’s non-invasive nature would increase patient comfort and lower the risk of side effects.

As the first and largest study in this area, the results showed promising outcomes for patients using HIFU. The lead researcher, Andre Luis Abreu, M.D., assistant professor of clinical urology, and his team worked to assess whether HIFU could be effective as a strategy to target a specific area of the prostate, thereby controlling cancer spread. The team’s results proved HIFU to be effective at doing so. Such a development gives more than 90 percent of men with localized prostate cancer the opportunity to avoid or delay radical treatment options.

“Short-term results of focal indicate safety, excellent potency and continence preservation, and adequate short-term prostate cancer control,” the researchers wrote.

Diagram showing high-intensity focused ultrasound (HIFU) use on the prostate to control cancer
Diagram showing how high-intensity ultrasound (HIFU) is performed

Enrolling 100 men with localized prostate cancer, the study was conducted in a four year period from December 2015 to December 2019. The average age of participants was 65. Upon entering the study, participants’ prostate cancer had varying levels of risk. Half of the men had intermediate favorable risk. In addition, 8 percent had very low risk, 20 percent had low risk, 17 percent had intermediate unfavorable risk, and 5 percent had high risk.

Moreover, the researchers collected data on erectile dysfunction (ED), complications 90 days after high-intensity focused ultrasound, and prostate symptoms score. The outcomes of participants were assessed for an average of 20 months. The study defined failure as prostate cancer recurrence, need for radical treatment, metastasis, systemic therapy, or mortality specifically from prostate cancer.

Upon reviewing participant outcomes, the study found that 73 percent of men avoided treatment failure. Additionally, 76 percent had no evidence of clinically significant prostate cancer. High-intensity focused ultrasound’s non-invasive nature also meant that 100 percent retained continence – something which is typically affected in more radical treatments. Two years following treatment, 91 percent of the participants were able to avoid radical treatment. Only 13 percent of the men experienced minor complications.

Focal One HIFU machine
An example of a HIFU system from Focal One

“We believe these data represent the actual clinical practice in the United States,” wrote the researchers. “This study provides the initial U.S. HIFU data to prostate cancer stakeholders, including clinicians, patients, and the FDA.”

In the future, high-intensity focused ultrasound may become a standard option for prostate cancer treatment. The non-invasive approach eliminates many of the side effects commonly experienced with other methods, and the initial results of the study show that it could have a significant place in the physician’s toolbox. Ultrasound use for therapeutic applications has expanded in recent years with some researchers trying to use the modality as a treatment option for Alzheimer’s and diabetes. HIFU’s newfound potential as a prostate cancer treatment is only a glimpse into the many applications ultrasound may have in the future.