Novel HIFU approach effective as alternative to radical prostate cancer treatments

Magnetic resonance (MR)–guided focused ultrasound (MRgFUS) focal therapy has shown promise as alternative to surgery, chemotherapy, and radiation in some men with intermediate-risk prostate cancer, according to findings published in Lancet Oncology.^1,2

Results from a phase 2b study (NCT01657942) of MRgFUS showed that at 24 months, 88% of men had no evidence of grade group 2 or 3 prostate cancer in the treatment area according to targeted prostate biopsy. Additionally, 60% of men had no evidence of grade group 2 or 3 disease anywhere in the prostate gland, including outside of the treatment area. Serum PSA levels decreased by almost 50% after treatment and stabilized after 6 months.

Behfar Ehdaie, MD

“We believe this novel treatment strategy will improve the lives of many prostate cancer patients,” lead study investigator Behfar Ehdaie, MD, MS, a urologic surgeon at Memorial Sloan Kettering Cancer Center, stated in a news release. “To draw a parallel with how breast cancer treatment changed 30 years ago, you could think of focal therapy as a ‘male lumpectomy.’ Instead of removing all the tissue in a breast or prostate, we have learned that it is safe and effective to treat specific areas and greatly reduce the burden on patients.”

Ehdaie and colleagues explored MRgFUS as an alternative therapy that reduces side effects while maintaining cancer control by targeting areas of no cancer within the prostate gland. The ExAblate MR-guided focus ultrasound device delivers targeted high intensity focused ultrasound therapy through the rectum.

The study was a single-arm, multicenter trial. Men (N = 101) were treated at 7 academic centers and 1 private practice. MRgFUS was delivered focally to the lesion with a margin of normal tissue of greater than or equal to 5 mm based on planning. Treatment was monitored with real-time MR thermometry. Concurrent grade group 1 prostate cancer foci were not treated.

Men with untreated unilateral and more visible, grade group 2 or 3 prostate cancer were eligible. Patients were excluded if they were unable to undergo MRI or had large calcification between the rectum and the planned targeted treatment zone that could interfere with treatment.

Patients underwent targeted and systematic biopsies at 6 and 24 months after treatment, and examinations with quality of life measurements every 3 months.

The primary end points were efficacy and safety. Secondary end points included change in baseline patient-reported quality of life at 24 months.

The average patient age was 63 years and 86% of the cohort was White. The median PSA was 5.7 ng/mL. Eighty-four patients had at least clinical stage T1c disease. Seventy-eight percent of patients were in grade group 2 and 22% were in grade group 3.

Investigators recorded no serious adverse events (AEs). Most minor or moderate AEs self-resolved by 90 days. Two patients had ejaculation disorder and 1 had hematospermia beyond 90 days.

Erectile function scores were slightly worse at 24 months compared with baseline (HR, -3.5; 95% CI, -5.4 to -1.6). Ten (13%) reported no sexual activity and 81% of patients achieved erections adequate for intercourse.

Lower urinary tract symptoms were similar at baseline and 24 months (mean score difference, 1.1; 95% CI, 0.33-1.8).

“Advancements in prostate cancer over the past two decades have been headlined by successes that have benefited all patients, and now focal therapy provides another exciting area that can move the needle in prostate cancer management,” stated Ehdaie.

References

1. Ehdaie B, Tempany CM, Holland F, et al. MRI-guided focused ultrasound focal therapy for patients with intermediate-risk prostate cancer: a phase 2b, multicentre study [published online ahead of print]. Lancet Oncol. doi: 10.1016/S1470-2045(22)00251-0.

2. High-Intensity Focused Ultrasound (HIFU) Can Control Prostate Cancer With Fewer Side Effects. Published online June 14, 2022. Accessed June 27, 2022. https://bit.ly/3OAfvvk.