High intensity focal ultrasound (HIFU)
According to the guidelines, treatment with high-intensity focused ultrasound (HIFU) is considered experimental therapy and should therefore only be used in studies. This was again confirmed by leading experts at the annual conference of the German Society of Urology (DGU) in 2018.
High-intensity focused ultrasound, HIFU for short, is a procedure for the treatment of localized prostate cancer. In this process, bundled ultrasound waves hit the prostate with high energy and destroy the tumor tissue through the strong effect of heat. Although the HIFU procedure is intensively promoted, the effectiveness of the therapy has not yet been sufficiently researched and proven in studies. Compared to established methods, significantly fewer prostate cancer patients have been treated with HIFU worldwide. In addition, there is insufficient knowledge about side effects that can only occur years after completion of treatment.
Although there has been experience with HIFU therapy for several years, the study results are still unsatisfactory. According to a study1 on HIFU therapy published in the British Journal of Urology in 20101 , 80 percent of men with localized prostate cancer had a biochemical relapse five years after treatment, which in most cases indicates renewed tumor growth. Accordingly, only 20 percent of men were considered cured after five years. Since then, not much has changed. For example, a study2 published in April 2018 with data from prostate cancer patients from five German centres shows that tumor tissue was still detectable in more than one in four men one year after HIFU therapy. In a recent British study3 , HIFU therapy had to be repeated in every third patient with high-risk prostate cancer.
Disadvantages of HIFU treatment
In contrast to benign prostate enlargement, prostate cancer usually develops in the area of the prostate capsule and thus in the immediate vicinity of the rectum. HIFU treatment of the tumor therefore carries the risk of intestinal injury and fistula formation4. In many cases, the strong heat effect on the organ also has a negative effect on male potency. Although a partial treatment to maintain potency is possible, the prostate tissue is not completely removed and therefore the final removal of the tumour is not guaranteed.
In order to treat prostate glands with a larger volume with HIFU therapy, the prostate must be surgically reduced in size (TURP) beforehand, as otherwise no sufficient energy is reached in the inner zones of the organ. This can then no longer be called a "minimally invasive procedure".
1Ripert T et al.: Six years' experience with high-intensity focused ultrasonography for prostate cancer: oncological outcomes using the new 'Stuttgart' definition for biochemical failure. BJU Int. 2010 Nov 17.
2Ganzer R, Hadaschik B, Pahernik S et al.: Prospective Multicenter Phase II Study on Focal Therapy (Hemiablation) of the Prostate with High Intensity Focused Ultrasound. J Urol. 2018 Apr;199(4):983-989.
3Guillaumier S, Peters M, Arya M et al.: A Multicentre Study of 5-year Outcomes Following Focal Therapy in Treating Clinically SignificantNonmetastatic Prostate Cancer. Eur Urol. 2018 Oct;74(4):422-429.
4Netsch C, Bach T, Gross E, Gross AJ. Rectourethral Fistula After High-intensity Focused Ultrasound Therapy for Prostate Cancer and Its Surgical Management. Urology. 2011 Jan 5.