MRI-guided HIFU shows strong potential in localized prostate cancer

February 4, 2021
Jason M. Broderick

MRI-guided focused ultrasound ablation was highly effective with minimal side effects.

MRI-guided high-intensity focused ultrasound (HIFU) achieved impressive early outcomes in patients with localized intermediate-risk prostate cancer, according to phase 2 findings published in the journal Radiology.1,2

Among 44 patients treated with the MRI-guided focused ultrasound ablation technique, 93% (41 patients) no longer had clinically significant prostate cancer at the treatment site on a biopsy (median, 7 cores) done at 5 months posttreatment, meeting the primary end point of the trial.

The study defined clinically significant prostate cancer as a patient having ≥6 mm grade group (GG) 1 disease or any volume of ≥GG2 disease.

The investigators also reported that at 5 months’ follow-up, scores for erectile function and prostate symptoms were similar to baseline scores.

The procedure was associated with “minimal side effects,” according to the paper, with no incidents of major treatment-related adverse events.

"By combining the high-intensity focused ultrasound device with MRI, we can target our treatment to the exact location, because we're able to pinpoint precisely where the tumor is," principal investigator and lead author Sangeet Ghai, MD, Toronto's Joint Department of Medical Imaging, part of the University Health Network Sinai Health and Women's College Hospital, stated in a press release.

"The results so far have been very good," added Ghai. "We treated a smaller area using this device, yet still had very good results. At the same time the patients preserved their erectile and urinary function."

Eligible men were aged 50 years or older and had intermediate-risk prostate cancer, a prostate-specific antigen (PSA) level of 20 ng/mL or less, and less than 20 mm of MRI-visible GG 2 or GG 3 disease as determined by transrectal US-guided systematic and targeted biopsy.

The 44 patients received transrectal MRI-guided focused ultrasound. Thirty-six of the 44 patients had GG2 disease and the remaining 8 had GG3. The median age was 67 years (interquartile range, 62-70).

Highlighting a benefit of using MRI with HIFU, Ghai stated, "MRI almost instantaneously gives feedback as to the temperature that we've been able to achieve at the site. If the temperature was not what I wanted to get, I can reheat that area so that chances for successful treatment increase."

Across the patient population, median scores on the International Index of Erectile Function-15 (IIEF-15) were 61 at baseline and 53 at 5 months (P = .18). International Prostate Symptom Score (IPSS) results were 3.5 at baseline and 6 at 5 months (P = .43).

About 20% to 30% of all patients with prostate cancer who undergo surgery or radiation therapy would be candidates to receive some form of focal therapy such as MRI-guided HIFU, according to Ghai.

(Credit for image on homepage associated with article: Radiological Society of North America.)

References

1. Ultrasound technique treats prostate cancer with minimal side effects. Published online February 2, 2021. Accessed February 4, 2021. https://bit.ly/3rpQfMS.

2. Ghai S, Finelli A, Corr K, et al. MRI-guided focused ultrasound ablation for localized intermediate-risk prostate cancer: early results of a phase II trial [published online ahead of print February 2, 2021]. Radiology. doi: 10.1148/radiol.2021202717