LAS VEGAS — Focused ultrasound ablation for prostate cancer proved at least equivalent to radical prostatectomy for failure-free survival, according to a randomized trial reported here.

After 3 years of follow-up, treatment failure had occurred in 5.6% of patients treated with focused ablation and 7.9% of the prostatectomy groups. The difference did not achieve statistical significance but met the trial’s primary endpoint of non-inferiority for focal ablation versus surgery.

The FARP (Focal Ablation versus Radical Prostatectomy) study was the first randomized controlled trial of focal ultrasound ablation and surgery for prostate cancer and has implications for future management of intermediate-risk prostate cancer, said Eduard Baco, MD, PhD, of Oslo University Hospital in Norway, at the American Urological Association (AUA) meeting.

“Our final 3-year results met the primary endpoint of showing non-inferiority between the two arms of the trial, with the results showing a lower rate of treatment failure in the focal ablation arm compared to the robotic prostatectomy arm,” said Baco. “The findings from this randomized controlled trial provide significant additional evidence that support the use of focal ablation with ultrasound energy for the management of organ-localized prostate cancer, in particular HIFU [high-intensity focused ultrasound].”

Part of a program that included studies of multiple focal ablation technologies, the FARP trial reflects the growing interest in therapeutic alternatives to surgery and radiation, said David Chen, MD, of Fox Chase Cancer Center in Philadelphia.

“We’ve gone from being a fringe option to being recognized as a level of treatment on par with surgery and radiation,” Chen told MedPage Today. “All of these [technologies] are probably similar in their effectiveness, and we’re gaining a better understanding of the specific scenarios that one may have some particular benefit over another.”

Fielding questions after his presentation of the FARP data, Baco said 8% of patients in the focal ablation arm required repeat treatment. Patients randomized to focal ablation were treated with HIFU or transurethral ultrasound ablation (TULSA). HIFU was used for all retreatment procedures, he said.

The FARP results added to growing evidence that focal ultrasound ablation offers a safe and effective treatment option for selected patients with localized prostate cancer. The results resembled those of a large non-randomized French study reported a year ago at AUA, showing that 89.8% of patients treated with HIFU were free of the need for salvage treatment after 30 months, as compared with 86.2% of patients who had radical prostatectomy.

Based in Norway, FARP included 213 patients with intermediate-risk, unilateral prostate cancer on MRI and biopsy. Eligible patients had >5 mm International Society of Urological Pathology (ISUP) grade 1 lesions or any ISUP grade 2-3 lesions, prostate specific antigen level ≤20 ng/mL, and age younger than 80.

Patients randomized to focal ablation received HIFU for posterior tumors and TULSA for anterior tumors. Patients randomized to surgery underwent robotic unilateral nerve-sparing prostatectomy. All patients had follow-up that included PSA measurement, and patients treated with focal ablation had MRI assessment and systematic biopsies at 1 and 3 years.

The primary endpoint was treatment failure. For the focal ablation group, failure was defined as need for secondary radical prostatectomy or radiation therapy because of high-risk prostate cancer ineligible for repeat ablation. In the prostatectomy group, failure was defined as a postoperative PSA value >0.2 ng/mL.

Subsequently, five patients refused any treatment. The crossover rate was 13%, primarily from radical prostatectomy to focal ablation.

The study population had a mean age of about 65, PSA value of 8.5 ng/mL, tumor diameter on MRI of 14-15 mm, and prostate volume of 41 mL. More than 70% of patients had ISUP 2 lesions, and about a fourth had ISUP 3 lesions.

By intention-to-treat analysis, the 2.3% difference in treatment failure at 3 years fell well within the prespecified non-inferiority threshold of 15% for comparison of focal ablation versus prostatectomy. A per-protocol analysis yielded treatment failure rates of 5.3% for focal ablation and 9.1% after radical prostatectomy.

Baco previously reported that focal ablation was associated with significantly fewer serious (Clavien-Dindo ≥3) complications (2% vs 13%, P<0.001). Rates of Clavien-Dindo 1/2 complications numerically favored focal ablation (17% vs 25%, P=0.18).

Please enable JavaScript to view the

comments powered by Disqus.