COMMENTARY

HIFU for Prostate Cancer: Efficacy Data 'Lacking'

FDA Considers Denying Ablatherm's Approval in Absence of Evidence

Gerald Chodak, MD

Disclosures

August 11, 2014

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This is Dr. Gerald Chodak, for Medscape. This week, I want to discuss a US Food and Drug Administration (FDA) panel recommendation about the Ablatherm® HIFU (high-intensity focused ultrasound) device (EDAP TMS; Lyon, France).

The recommendation of the panel was that it should not be approved for routine use in men with low-risk prostate cancer. Most people on the panel felt that it was not safe, and an almost unanimous group felt that its effectiveness was unclear.

How did they get to this decision? What were the data that went into their analysis? Originally, a comparative trial with cryotherapy for low-risk disease was planned, but that trial was discontinued owing to poor recruitment. They ended up with case studies and a meta-analysis looking at 920 men with low-risk disease, of whom only 227 were available for a variety of exclusion reasons. Part of the problem was that some men had received transurethral resection of the prostate (TURP) procedures, androgen-deprivation therapy, or a combination of these treatments, making any analysis or comparison with other therapies more difficult.

The panel found that the overall effectiveness of HIFU was unclear. The studies were not mature. Biochemical recurrence was used as an outcome, and the FDA doesn't consider that a valid outcome. They consider either metastasis or overall survival, and there were very limited data on those endpoints. In fact, only 94 men out of the 227 were followed for more than 8 years, so the analysis was based on a small number of patients.

The complications and side effects were significant. Urinary retention occurred in 1%-20%, urinary tract infection occurred in 2%-48%, incontinence occurred in 1%-34% and erectile dysfunction occurred in 20%-82% of men. The bottom line is that the efficacy was very low and the high rate of side effects, although comparable to radical prostatectomy, was difficult to accept in the absence of data proving efficacy.

Another problem was that 15% of the patients were re-treated within 1 year and 34% had salvage therapy, which frequently was a repeat procedure. Overall at 8 years, the failure rate or the need to re-treat was about 40%.

It is difficult to understand why people are so enthusiastic about HIFU in the absence of better data. A major argument has been that some 40,000 men worldwide have been treated with HIFU in the past 15 years, and despite that number of men, the data demonstrating efficacy have been lacking. A review by a Canadian group[1] and a review from France[2] concluded that the data were just too immature and inadequate to make valid comparisons of its effectiveness overall.

We have yet another therapy for which due diligence has not been done to prove efficacy, and despite the enthusiasm that treaters have for this treatment, the fact is that there are no good data supporting its use. To cite a large number of men who seemingly did well is certainly not proof of benefit because, as we know, a high percentage of those men had a treatment that they didn't need -- and certainly didn't benefit from.

For now, hopefully the FDA will follow this recommendation and deny an approval for the Ablatherm device. There is a Sonablate® device (SonaCare; Charlotte, North Carolina) also going through clinical trials, but that is being tested in men who have failed local therapy. Hopefully those data will be better.

We also can hope that the manufacturer of Ablatherm will do better trials to try to demonstrate whether this is truly an effective treatment for prostate cancer, but until then, men throughout the United States should realize that not only is HIFU not approved in the United States, but the FDA panel found noncompelling evidence that it was an effective treatment for low-risk prostate cancer.

I look forward to your comments. Thank you.

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