HIFU for Prostate Cancer: Think Twice
Searching for a “magical” cure for prostate cancer, and believing the stories of men who had purportedly found such cures, patients have long traveled abroad in search of therapies not approved for use in the United States by the Food and Drug Administration. Notably, in recent years some men with prostate cancer have gone overseas to receive a treatment called high intensity focused ultrasound (HIFU).
Because of a recent change in federal regulations, however, medical clinics in this country are now permitted to offer HIFU as a treatment for diseases of the prostate, including cancer.
However, the FDA has not expressly approved HIFU as a treatment for prostate cancer, and this therapy’s value and safety remain controversial. If you have recently been diagnosed with prostate cancer, here’s what you should know before considering HIFU.
Ultrasound as therapy
HIFU uses ultrasound technology to destroy diseased tissue. Most people are familiar with ultrasound as a medical-imaging technique for producing pictures of structures inside the body, which it achieves by emitting sound waves and capturing them as they bounce back.
However, high-energy ultrasound waves can also kill tissue by generating temperatures up to 176° F (80° C). HIFU also kills tissue by causing cells to collapse.
HIFU was initially studied in the early 1950s as a treatment for Parkinson’s disease. Clinical trials of HIFU for prostate cancer began in the 1990s and the therapy has been used to treat the disease for more than 15 years. It is already available in Europe, Canada, Japan, and other countries.
HIFU can be used to remove a man’s entire prostate. However, the technique is commonly administered as a form of focal therapy, a relatively new strategy that is sometimes used to treat small prostate tumors that have not spread beyond the gland. Traditional treatments such as radical prostatectomy and external beam radiation remain the standard of care for prostate cancer; those so-called “whole gland” therapies aim to treat the entire prostate, along with some surrounding tissue.
By contrast, the goal of focal therapy is to destroy only the tumor, while sparing the prostate gland and other nonmalignant tissue (such as nerves) from harm. Cryotherapy is another type of focal therapy; it takes the opposite approach to HIFU by freezing tissue within the prostate.
Despite growing interest in focal therapy, it remains an investigational treatment, and has been primarily studied in men with very low-risk prostate cancer.
HIFU and the FDA
HIFU is used to treat other diseases of the prostate, including benign prostatic hyperplasia (BPH), also known as benign prostatic enlargement (BPE), as well as other medical conditions (such as uterine fibroids).
Here's how HIFU is used to treat prostate disease: After a patient is sedated, the doctor inserts a probe through the rectum. The probe uses ultrasound imaging to visualize the prostate, allowing the doctor to make a “map” of which zones to treat.
Next, the doctor uses the probe to apply high-intensity ultrasound waves to the targeted area, heating up a spot the size of a rice grain. This process is repeated until the targeted area is destroyed. The procedure takes two to four hours, depending on prostate size and the number of tumors.
Proponents of HIFU emphasize its advantages over other treatments for prostate cancer. For instance, the procedure doesn’t require an incision or result in any blood loss, and the patient isn’t exposed to any radiation.
HIFU is performed on an outpatient basis and recovery is speedy—men are usually up and around within hours of the procedure. Some providers insist that HIFU treats prostate cancer as well as surgery and radiation.
However, it’s important to consider such claims with caution, because many questions remain about the overall safety and effectiveness of HIFU.
That much became clear when a French company called EDAP asked the FDA to approve its HIFU device, called the Ablatherm HIFU, for the treatment of low-risk prostate cancer that has not metastasized, or traveled, outside the gland. (The device name comes from “ablation,” which refers to the removal of tissue, and “thermal,” which means “caused by heat.”)
In its FDA application, EDAP noted that the Ablatherm HIFU had been used to treat more than 40,000 patients around the world.
To demonstrate the technology’s effectiveness to the FDA, EDAP conducted a meta-analysis (an analysis that combines the results of many individual studies to reach a single conclusion) of HIFU for treatment of low-risk prostate cancer.
The company argued that the results showed HIFU’s effectiveness in treating prostate cancer that has not metastasized.
An expert panel appointed by the FDA to evaluate EDAP’s application disagreed with that assessment. In particular, it noted that 28 percent of men who underwent HIFU had positive biopsies for prostate cancer two years later, a figure that members of the panel felt was too high; with more than one in four patients experiencing a cancer recurrence, it appears that the HIFU probe frequently fails to completely eradicate the cancer. The FDA decided to reject EDAP’s application for the Ablatherm HIFU in 2014.
The story continues
The FDA’s rejection wasn’t the end of the story for HIFU in the United States, however. A year later, a company called SonaCare asked the FDA for permission to sell its HIFU device, called Sonablate, in this country.
However, instead of seeking approval to market Sonablate for the treatment of prostate cancer, SonaCare simply sought permission to sell its device for “prostate tissue ablation.”
In October 2015 the FDA cleared the way for Sonablate to be sold in the United States for ablation of prostate tissue. A few weeks later the FDA granted EDAP the right to market the Ablatherm HIFU.
Because the FDA does not regulate the practice of medicine, there are no legal restrictions prohibiting doctors in the United States from using these HIFU devices to treat prostate cancer, as they now do at a number of clinics around the nation.
Is HIFU for you?
If you have prostate cancer, there are several good reasons to think twice before pursuing HIFU as a treatment option. For starters, the overall quality of research on this therapy leaves a great deal to be desired, so we still don’t know enough about its efficacy, especially when used as focal therapy.
One study found that 88 percent of men with low-risk prostate cancer who had HIFU were cancer-free (as measured by PSA testing) five years later, but only 48 percent of patients with high-risk disease who had HIFU fared as well.
A 2015 study of 918 HIFU patients published in the Journal of Urology found that 87 percent had negative biopsies six months later, though the majority of the men studied had low-risk prostate cancer to begin with.
While HIFU boosters claim the procedure is safer than other approaches, it’s by no means free of side effects. The risk of erectile dysfunction (ED) is greater in men undergoing whole-gland HIFU therapy (as high as 77 percent in one study) than in focal therapy, which has found post-operative ED rates ranging from 11 percent to 45 percent.
However, a 2016 study in European Urology found that ED triggered by HIFU responded to medication and often diminished within one year. Urinary problems are another common side effect.
But the biggest adverse effect from HIFU could be the harm to your wallet. Most insurers will not cover the cost of treatment, so pursuing this ultrasound-based therapy could prove to be ultra-expensive.