High-intensity focused ultrasound (HIFU) is a radiation-free therapy that has been approved by the Food and Drug Administration for prostate tissue ablation, which means it can be used to treat prostate cancer, although the approval is not specifically for that. Thus far, two types of HIFU systems have garnered the FDA’s okay: the Sonablate 450 (approved October 2015) and Ablatherm HIFU (November 2015).
Although HIFU is relatively new to the prostate cancer treatment scene in the United States, the technology has been available in Europe, Asia, and elsewhere around the world for more than 15 years, where it has been used to manage benign prostatic hyperplasia, localized whole-gland prostate cancer, and recurrent prostate cancer. According to SonaCare Medical, which developed the Sonablate 450, more than 50,000 men have been treated with HIFU for prostate cancer globally. Now men in the United States will have access to this therapeutic approach.
What Is HIFU?
HIFU uses ultrasound instead of radiation to treat certain types of cancer, including those affecting the prostate, kidney, bladder, pancreas, and liver. The high frequency sound waves emitted from an HIFU device have the ability to kill cancer cells associated with a single tumor or part of a large tumor. HIFU is not appropriate for cancer that has spread (metastasized) beyond one site in the body.
When HIFU is used to treat prostate cancer, the ultrasound waves are sent through the rectum walls, where they generate sufficient heat to destroy cancerous prostate cells. HIFU is designed to destroy prostate cancer cells while also preserving the integrity of the prostate gland, which minimizes the occurrence of side effects.
What happens during HIFU treatment?
Men who undergo HIFU for prostate cancer can expect a scenario similar to the following. Patients disrobe and lie on their side on a treatment table. The HIFU machine has a transrectal probe, which is guided gently into the rectum. This procedure is performed under either spinal or general anesthesia and takes 2 to 3 hours to complete.
Sonablate 450 utilizes specialized software that allows the clinician to pinpoint the targeted treatment areas while sparing surrounding tissue and to track treatment with advanced real-time ultrasound imaging and simultaneous displays to a monitor. The Ablatherm HIFU uses real-time 3-dimensional imaging, which allows the clinician to precisely deliver the ultrasound and monitor the progress of the ablation.
Who is a candidate for HIFU?
Men who have localized prostate cancer can be candidates for HIFU. In a 2015 review in the Polish Journal of Radiology, the authors noted that HIFU is indicated for men who are not candidates for prostatectomy because of general health issues, age, or a preference to not undergo surgery. In addition, HIFU can be used for men who have not responded to or have recurrent prostate cancer after radical prostatectomy, hormone ablation, or radiation therapy. It is also appropriate as an alternative to surgery or radiation, and it can be also be used in surveillance patients whose disease is progressing.
How does HIFU compare with prostatectomy?
Limited research has compared HIFU and prostatectomy. However, several benefits are clear, not least of which is the lack of incisions, which results in fewer complications, less discomfort, and the ability to return to normal activities sooner. Prostatectomy is a surgical procedure that is performed in an operating room while HIFU is an outpatient procedure. While HIFU is limited to destroying the cancerous tissue in the prostate, prostatectomy involves removing the entire gland.
In a matched pair comparison study of 588 men treated between 2000 and 2005 with either HIFU or prostatectomy (294 in each group), researchers observed that at nine years, the overall, cancer specific, and metastasis-free survival rates were similar between the HIFU and prostatectomy groups; namely, 89%, 97%, and 94% vs 89%, 97%, and 97%, respectively.
Side effects associated with prostatectomy are considerable. A Reviews in Urology study reported the following:
- Urinary incontinence: Most men experience some urine leakage for several weeks following surgery, but the condition typically resolves within a few months for the vast majority of men
- Erectile dysfunction: Occurs in nearly all cases immediately after surgery. Although erectile function can return, it can take 18 to 24 months or longer
- Ejaculatory dysfunction: Occurs in all men
- Retrograde ejaculation: Develops in 40 to 90 percent of men
- Orgasmic issues: Occurs in about 50 percent of cases
- Penis shrinkage: Frequent occurrence that can worsen over time
- Nocturnal and morning erections: Men typically lose these erections immediately following surgery, although they do return over time
What side effects are associated with HIFU?
After undergoing HIFU, men can expect to experience some discomfort, frequent and/or urgent urination, and minimal urinary leakage. The occurrence of other side effects is somewhat dependent on the skill of the clinician as well as whether the procedure was performed to help correct (salvage) the failure of another, previous treatment such as prostatectomy or radiation. Since HIFU is relatively new and requires a high degree of skill, side effect and complication rates can vary.
For example, according to the International HIFU organization, overall 70 to 95 percent of men maintain erectile function and 93 to more than 99 percent maintain urinary continence. A 2010 study published in Prostate Cancer and Prostatic Diseases reported some different statistics. Based on 68 HIFU procedures, the authors reported the following early complication rates: 20 percent urinary retention, 3.6 percent urinary infection, 3.6 percent blood in the urine, and 3.6 percent urethral stenosis (blockage of the urethra). Complications noted to occur later after the procedure included 9 percent urethral stenosis and 3.6 percent painful urination. Long-term urinary incontinence rate was 20 percent and new onset of erectile dysfunction rate was 77.1 percent.
What’s the bottom line regarding HIFU for prostate cancer treatment?
Men who are considering HIFU as a treatment strategy for prostate cancer should seek out a qualified professional who has performed a significant number of the procedures. They also should speak with other men who have undergone the procedure.