Visually Directed Transrectal High Intensity Focused Ultrasound For The Treatment Of Prostate Cancer: A Preliminary Report On The Italian Experience

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Cancer / Oncology
Article Date: 14 Feb 2009 - 1:00 PDT

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UroToday.com - Radical prostatectomy is the gold standard in patients with organ-confined prostate cancer, with excellent long-term survival rates, even if surgery is associated with significant morbidity. High-intensity focused ultrasound is a non invasive technique for the thermal ablation of tissue, and it is one of the most attractive options for the non-invasive treatment of localized prostate cancer, even if only more extensive follow up studies and hopefully a randomized control trial comparing HIFU with other form of treatment will definitively place HIFU in the armamentarium of prostate cancer control.

The first point, for a successful procedure, is patient selection: in most series HIFU has been recommended for patients with localised prostate cancer, Gleason score ≤7, PSA value ≤15-20 ng/ml, and it has also been used for locally advanced disease or radiation or brachytherapy failure.

In our experience we treated patients with low, intermediate, high-risk prostate cancer and also limited cT3a disease, with the aim to identify best candidates to HIFU treatment. Effectively, as demonstrated by bNED survival rates and prostate biopsy findings, best results are achieved for low and intermediate-risk disease according to D'amico risk classification, while high and very-high risk disease presented an unacceptable risk of biochemical relapse and/or positive biopsy findings.

The second point is definition of response: the most accepted definition of disease-free status is ASTRO criteria; other authors have used the new Phoenix definition of biochemical failure (i.e., PSA nadir plus 2 ng/ml): according to this definition, overall 5-years biochemical disease-free rate was 77% in patients with low-intermediate risk prostate cancer. According to Phoenix criteria, in our series overall bNED is 78.2%, and the results for low and intermediated risk group are comparable to the outcome of patients treated with brachytherapy.

The third point is the definition of a surrogate for predicting treatment failure. Most authors agree that PSA nadir can be used to predict the risk of biochemical failure or residual disease, but to date the correct PSA-nadir cut-off has not been yet defined even if, like for radical prostatectomy, a value < 0.20 ng/ml seems to be the best predictor of treatment failure. In our experience, using PSA nadir with a cut-off of 0.40 ng/ml, PSA nadir becomes the only independent predictor of positive biopsy at multiple logistic regression analysis and of bNED at Cox regression analysis, together with risk stratification.

In conclusion, as for other minimally invasive treatments, patients need to be carefully selected, and it could be reserved for patients with low-intermediate risk disease. Prostate biopsy and PSA nadir are the best surrogate to define disease control. Phoenix criteria, even if originally created for definition of bNED for radiation treated patients, seems to be helpful in defining the success of the procedure.

Written by Luigi Mearini, MD as part of Beyond the Abstract on UroToday.com

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