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Sonablate Phase I/II Study
The December 2007 Journal of Urology included an article entitled “Phase
I/II Trial of High Intensity Focused Ultrasound for the Treatment
of Previously Untreated Localized Prostate Cancer” (hereinafter “Phase
I/II Trial”). It was written by Michael O. Koch, Thomas Gardner,
Liang Cheng, Russell J. Fedewa, Ralf Seip, and Narendra T. Sangvhi—all
associated with the Department of Urology at Indiana University
School of Medicine and/or Focus Surgery, Inc., the manufacturer
of the Sonablate 500 HIFU device. The article provides a review
of the study performed using the Sonablate 500 as the first step
toward trying to get FDA approval for the device. The results portion
of the study abstract follows:
Results: A total of 19 patients had complete
followup. Serious adverse events related to treatment were
limited with the most common adverse event being transient
urinary retention more than 30 days in duration in only 10%
of patients. Rectal injury occurred in 1 patient. With 1 to
3 treatments 42% of the patients achieved prostate specific
antigen less than 0.5ng/ml and a negative prostate biopsy.1
If the goal of the study was to demonstrate the safety and efficacy
of the Sonablate device,2 it does not appear that
this goal was achieved. In 60% of the cases, at least one additional
HIFU treatment was required. More importantly, even with multiple
treatments, only 42% of patients had a PSA of <0.5ng/ml and
a negative prostate biopsy; i.e., in 58% of patients the Sonoblate
did not effectively treat the cancer.
Dr. Christian Chaussy, one of the most experienced physicians
using HIFU in the world, in his editorial comment on the article,
stated “According to the authors the primary goal of the
study was to document the safety of the method and secondarily
to show the potential efficacy of transrectally delivered HIFU
with the Sonablate. Neither topic shows convincing results.” In
addition, “a 5% incidence of rectourethral fistula and
a urinary incontinence rate of 20% do not represent a low complication
rate.”
Patients should compare the Sonablate results detailed in its
FDA trial study with study results using the Ablatherm HIFU device.
In a presentation to the Northeastern Sectional meeting of the
American Urological Association in September 2007, Dr. Magdy
Hassouna of Toronto presented Maple Leaf HIFU’s results
using the Ablatherm:
- With a patient profile similar to the one in the Sonablate
study above (Gleason score 7 (3+4) or less, pretreatment PSA
10 ng/ml or less, and stage T1–T2 disease), 88% of Maple
Leaf patients achieved a PSA nadir of less than 0.5 ng/ml at
3 months.
- Only 2% of the patients treated represented biochemical (PSA
nadir + 2.0) or pathological (biopsy proven local recurrence/persistence)
failures.
- The remaining 10% of patients currently show no evidence
of biochemical or pathological failure. It is probable that
the success rates for this group as a whole will prove to be
even higher than the current 88%.
Morbidity rates are similarly in favor of Ablatherm. None of
Maple Leaf HIFU’s patients has developed a rectourethral
fistula (indeed, there have been no cases of fistulae reported
worldwide since software parameters were changed on the Ablatherm
in 2002). Incontinence issues, if any, were limited to irritative
symptoms experienced during the first three months and were resolved
by six months.
The high success rate obtained by Maple Leaf HIFU mirrors those
achieved with thousands of Ablatherm treatments across the world.
The total lack of rectourethral fistulae since 2002 and the virtual
absence of Type III urinary incontinence (significantly less
than 1%) are undoubtedly due to the failsafe mechanisms on the
Ablatherm (see http://hifu.ca/patient/hifu_devices.php);
the superior 7.5MHz real time ultrasound imaging; and the computerized
treatment system all of which allow for a precise treatment plan
and markedly reduce complications and/or residual cancer associated
with an operator dependent system.
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