Jean-Yves Chapelon, Ph.D
Directeur de Recherche
INSERM Unite 281
Lyon Cedex03 - France
Transrectal High-Intensity Focused Ultrasound: Minimally Invasive
therapy of localiZed prostate cancer.
With the advent of the PSA test, an increasing number of
prostate cancers are being detected at a local stage. Since
1989, our group has been developing a research project with
the aim of establishing treatment of localized prostate cancer
by means of High-Intensity Focused Ultrasound (HIFU). The
treatment is administered transrectally, using ultrasound
guidance only. The quality of HIFU treatment depends on four
factors: the intensity of the wave emitted, the exposition-time,
the signal frequency, and the time between two firing-bursts.
The lesions are created by a thermal effect. Criteria for
determining the durability of the response to transrectal
HIFU ablation of prostate cancer have been recently established.
A series of 82 patients (mean age 71 ± 5.7 years) with
biopsy-proven localized (stage T1-T2) cancer who were not
candidates for radical surgery underwent transrectal HIFU
ablation with the Ablatherm™ machine. Progression was
rigidly defined as any positive biopsy result, regardless of
PSA levels, or 3 successive PSA increases for patients with
a negative biopsy (PSA velocity ≥ 0.75). Times to
specific events (positive biopsy and PSA elevation) were
analyzed with Kaplan-Meier survival analysis. Overall, 62%
of the patients exhibited no evidence of disease progression
60 months after transrectal HIFU ablation. In particular, the
disease-free rate was 68% for the moderate risk group of 45
patients (PSA <15.0 ng/ml, Gleason sum < 8, prostate
volume < 40 cm3 and number of positive biopsies
< 5). For the low risk group of 27 patients (PSA <
10 ng/ml and Gleason sum < 7), the disease-free survival
rate was 83%. These data indicate that transrectal HIFU
prostate ablation is an effective therapeutic alternative
for patients with localized prostatic adenocarcinoma.
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