MRI-Guided Focused Ultrasound Ablation Shows Promising Early Outcomes in the Treatment of Prostate Cancer

Targeted focal therapy using MRI-guided focused ultrasound ablation was safe and effectively treated patients with localized intermediate-risk prostate cancer, according to early data from a study published in Radiology.¹

The early oncologic and functional outcomes were encouraging to the research team, suggesting the current options such as surgery and radiation therapy that eliminate the cancer but often leave patients with incontinence and sexual dysfunction can be improved upon.

“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, said in a press release.²

Of the 44 men with prostate cancer who successfully underwent treatment, 36 men had grade group (GG) 2 and 8 had GG 3 disease. Median age for the 44 patients examined with prostate cancer was 67 years (interquartile range [IQR], 62–70 years).

At 5-month biopsy, 41 of the 44 patients examined (93%; 95% CI, 82%-98%) were free from clinically significant prostate cancer (³6 mm GG 1 disease or any volume ³GG 2 disease). There were no major adverse events observed.

More, the median International Index of Erectile Function-15 (IIEF-15) and International Prostate Symptom Score (IPSS) scores were similar at baseline and 5-months. The IIEF-15 score at baseline was 61 (IQR, 34–67), and at 5 months was 53 (IQR, 24–65.5, P = .18). For IPSS, the score was 3.5 at baseline (IQR, 1.8–7) and 6 at 5 months (IQR, 2–7.3, P = .43).

Looking at ablations larger than 15 cm3, the research team found an association of larger ablations with a decline in IIEF-15 scores at 6 weeks (adjusted P = .01) and at 5 months (adjusted P = .07) when compared with smaller ablations.

“The results so far have been very good,” Ghai said in a press release. “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.”

This study included men treated with transrectal MRI-guided focused ultrasound between February 2016 and July 2019 with clinically significant prostate cancer visible at MRI. The primary end point was 5-month biopsy, with follow-up of IIEF-15 and IPSS scores at 6 weeks and 5 months.

The research team acknowledged that due to the focus on early outcomes, a limitation of the data is the short follow-up period. More, the population was small and limited to men with unifocal clinically significant prostate cancer, which may not be generalizable to other patients with prostate cancer.

“Targeted focal therapy of intermediate-risk prostate cancer performed with transrectal MRI-guided focused ultrasound has encouraging early oncologic outcomes and a low rate of genitourinary adverse effects,” wrote the investigators.

References:

1. 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. Radiology 2021;298(3):695-703. doi: 10.1148/radiol.2021202717

2. Ultrasound technique treats prostate cancer with minimal side effects. News release. Radiological Society of North America. February 2, 2021. Accessed February 9, 2021. https://www.eurekalert.org/pub_releases/2021-02/rson-utt012621.php