High-Intensity Focussed Ultrasound (HIFU) for Prostate Cancer
At base, this is a treatment which is intended to kill cancer using heat generated by an ultrasound transducer. There is much discussion of this technique on the internet, despite the lack of robust evidence for it's use. The Food and Drug Administration in the United States has required the companies producing the devices to undergo clinical trials before they receive approval. However, these requirements have not extended to other jurisdictions such as Canada and the Carribean - 2 areas where the treatment is being offerred. It has been 'sold' as an effective, minimally invasive approach to treating prostate cancer. This is not the case.
It may not be made clear to patients by the physicians providing these treatments that HIFU is in fact experimental and under investiagion. The fact that they have received approval in some countries is more a reflection on the regulatory process than on the efficacy and safety of HIFU. The European experience is very limited in terms of patient treated and the length of follow-up. Short term follow-up in the treatment of prostate cancer is defined as a 'median follow-up of 5 years'. This does not mean that the technique has been used for 5 years, but that the majority of patients have been followed for at least 5 years and that the information from these patients are used to reach conclusions. The best type of study to evaluate a technique is a randomized controlled trial with long-term median follow-up of 5-10 years - HIFU does not currently this standard.
HIFU may eventually become an acceptable treatment modality for prostate cancer after research and refinement of the technique occurs. Focal treatment of prostate tumors (rather than removal of the entire gland) may eventually become a reality. Until that time, however, it should be considered experimental at this point in time.
There are a number of ongoing concerns regarding this technique
It is unknown if they are more or less effective than current techniques - or effective at all
It is unknown what the best way to assess results is - currently the radiation definitions are being applied but there is no clear rationale for why this is being used
It has been combined with treatments known to have the potential to cure prostate cancer which further confounds interpretation of the results
Salvage therapy with surgery and radiation, even when possible, is associated with an increased risk of side-effects. In effect, bridges are burnt with this technique.
Very serious side-effects have occurred, even with the 'modern, refined' approach now currently 'marketed'. These include rectourethral fistulae (a devastating complication), urethral and bladder neck contractures, incontinence, erectile dysfunction.
Here is a recent commentary by Dr. Gerald Chodak from Medscape on the Technique from January 30, 2012
Hello. I'm Dr. Gerald Chodak from Medscape. An article was recently published by Ahmed and associates in Cancer that looked at salvage high-intensity focused ultrasound (HIFU) for men who had failed radiation therapy.[1] The authors documented the status of patients who had prostate biopsies to confirm cancer and negative CT and bone scans to rule out metastatic disease, although microscopic disease was certainly possible. They performed HIFU at 2 different centers using Sonablate® equipment, and they captured and documented quality of life by using surveys for the patients to document side effects and outcomes.
I found the results to be disturbing on several levels. The side effects were the following: Although only 2 men developed a fistula after the initial treatment, 2 out of 6 men had developed a fistula when a second HIFU procedure was performed. The investigators found that about 20% of the men needed to undergo treatment for bladder outlet obstruction, which is certainly another concern. A significant number of men also noticed a drop in their sexual function. What I find most troubling about the results are the prostate-specific antigen (PSA) levels and biochemical and other means of failure. [Treatment was considered unsuccessful in] patients who had PSA > nadir + 2 ng/mL, a positive biopsy, or hormone therapy. At 1-year follow-up, 38% of the men had treatment failure, and at 2 years, 53% of patients had treatment failure.
If this treatment is truly effective, why is it not more effective at eliminating disease? Would it be more effective in men who had not received radiation? Does radiation somehow make HIFU more difficult to be successful, or is it also possible that the men are failing because the treatment is not an adequate way to treat prostate cancer, whether it is primary disease or secondary disease with recurrence? I think this whole issue is troubling. We get these new treatments that come along and are offered to patients without any formal study being done. We tell patients that we are testing it out, but they are not part of a formal study. As the data are accumulated, we tell them that the results look pretty reasonable when, in fact, they do not look very reasonable. Shouldn't we require that these newer treatments be fully evaluated with longer-term results to know whether they work rather than simply telling patients, "Yes, it's available, it's a reasonable option, and more results are needed"?
I think this is a problem that we have in treating prostate cancer, particularly because we now recognize that so many men are getting a treatment that they don't need. Is HIFU a good treatment when men don't need treatment at all, or is it truly effective when people have a serious disease that would progress unless treated adequately? It's true that this study primarily focused on recurrent disease, but the fact that it is not working very well for these men raises concerns about whether it's doing a good enough job for men who have never been treated before. Ultimately, I think that we need to solve this issue of new treatments that come along and find a way to really know whether they work before we let patients adopt them and assume that they are reasonable alternatives. I look forward to your comments. Thank you.
Ahmed HU, Cathcart P, Chalasani V, et al. Whole-gland salvage high-intensity focused ultrasound therapy for localized prostate cancer recurrence after external beam radiation therapy. Cancer. 2011 Nov 9. [Epub ahead of print]
On the Web
General Prostate Cancer Web-Resources
Prostate Cancer Canada Resources
Prostate Cancer Basics: Screening and Diagnosis
Prostate Cancer Treatment Options
Prostate Cancer Post-Treatment Recovery and Side Effects
Memorial Sloan-Kettering Cancer Center in New York is an excellent resource for information on prostate cancer. Balanced, unbiased discussions of the disease, including discussion regarding some of the controversies in prostate cancer.
General Information on Cancer
BC Cancer Agency: Good general website from the British Columbia Cancer Agency. Has contact information on locations.
National Cancer Institute: Excellent source of understandable and mainly unbiased information. Several very good brochures on every stage of prostate cancer.
National Comprehensive Cancer Network: peer-reviewed expert content/prostate cancer guidance on evidence-based cancer diagnosis and management. Best for Prostate and Kidney Cancer. The most in-depth information is located in the physician section and requires registration.