HIFU for hemiablation of localized prostate cancer

A major plenary presentation at the upcoming annual meeting of the American Urological Association (AUA) will provide data from a rather small French trial of  high-intensity focused ultrasound (HIFU) in the focal management of localized prostate cancer.

The presentation by Rischmann et al. (Plenary Session I; abstract no. 1150) will address the use of HIFU in the ablation of a single (cancer-containing) lobe of the prostate among a prospective cohort of men > 50 years of age with clinical stage T1c/T2a, a PSA of < 10 ng/ml, and a Gleason score of ≤ 7. All the patients were evaluated with a multiparametric MRI and biopsied prior to treatment. The trial was supervised by the French Urological Association.

The primary outcome of the trial was absence of clinically significant cancer (CSC) on post-treatment biopsy (Gleason < 7, less than two positive cores, and no cancer core length > 3 mm, regardless of grade).

Here are the data that Rischmann et al. will be presenting next month:

  • A total of 111 patients were enrolled and treated in this study.
  • The average (mean) age of the patients was 64.8 ± 6.2 years.
  • The average PSA level of the patients was 6.2 ± 2.6 ng/ml.
  • 74 percent of the patients had a Gleason score of 6 or less.
  • Patients were followed for 2 years post-treatment.
  • The radical treatment-free survival rate (no surgery, no radiation therapy, etc.) at 2 years was 89 percent.
  • The average (mean) decrease in PSA at 2 years was 62.9 percent from baseline.
  • The rate of adverse events was 12.6 percent for Clavien III adverse events.
  • At 12 months post-treatment
    • Urinary function was preserved in 97 percent of patients
    • Erectile function was preserved in 78.4 percent of patients.
    • There was no significant decrease in quality of life score.
  • 15/111 patients (14.9 percent) had clinically significant prostate cancers on re-biopsy post-treatment, of whom
    • 8 patients had prostate cancer in the lobe that had been treated
    • 7 patients had prostate cancer in the lobe that had not been treated.

The authors conclude that

After [h]emiablation HIFU the rate of clinically significant disease was low and associated with low morbidity and preservation of quality of life. This treatment strategy does not preclude future definitive therapies. Longer follow up is needed to confirm these promising results.

Once again, The “New” Prostate Cancer InfoLink is not exactly enthused by these data.

It is unclear how many of these patients really needed treatment at all. It is unclear how many of these patients were clearly told that they might do just as well on active surveillance (at least for a period of time) as they would after focal HIFU. The trial ran from 2009 through 2014, and, since all patients had to be followed for 2 years, this implies that patients were enrolled from 2009 to 2012, which is an average (and low) enrollment rate of 37 patients per year. And then the follow-up period is only 2 years.

As we mentioned earlier, in reference to the TOOKAD Soluble VTP trial (also a trial of focal hemiablation):

The availability of safe and effective treatments for men with low-risk disease will be a good thing … but only if they are used properly in the men who really need such treatment, and not if they are being used in men who would really do just as well (or perhaps even better) on active surveillance.

We need much better data from much larger trials to be able to make a really compelling argument that focal therapy of any type is a better idea for large numbers of men with low-risk disease than just monitoring those men on active surveillance until it is clear that they need treatment. For many of those men, focal therapy may still be a reasonable option at that point in time.

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