HIFU or High Intensity Focused Ultrasound is a prostate cancer therapy that destroys tissue with rapid heat elevation-which essentially "cooks" tissue inside the prostate. This is accomplished by ultrasound energy, or sound waves, that are focused at specific locations in the prostate. At these "focal points", the temperature raises to almost 90 degrees Celsius in a matter of seconds. Any tissue at the focal point is destroyed; however, any tissue outside of the focal point remains unharmed. The indications for using HIFU as a treatment for prostate cancer are for patients who are diagnosed at an early stage with a moderately aggressive cancer. Therefore, it is widely accepted that the best indications are patients who are suffering from cancer at a maximum of the localized T2c stage, without metastases, with a PSA less than or equal to 10, Gleason score less than or equal to 7.
HIFU is performed in an operating room. Patients are given a general anesthetic and an ultrasound probe will be placed in the rectum to image the prostate. The ultrasound probe is then used to focus high-intensity sound waves on a particular area of the prostate, causing heat that destroys the prostate tissue. The treatment time ranges from two to two and a half hours depending on the size of your prostate. The process is repeated over the whole area of prostatic tumor until all the cancerous tissue has been destroyed. A trans-urethral or supra-pubic catheter is left in place following the procedure for drainage of urine. This is because there will be swelling in the area which will impede your ability to pass urine. The catheter remains in for 3-14 days.
Because HIFU is a heat therapy focused inside the prostate gland, the likelihood of damage to the neurovascular bundle of nerves surrounding the prostate is minimized. This helps to preserve quality of life issues such as urinary continence and erection. Urinary incontinence is classified in grades with Grade 3 being severe or complete incontinence. After HIFU, Grade 1 incontinence occurs in less than 5% of cases. Grade 2 and 3 incontinence are very rare after HIFU occurring in less than 1% of cases performed as the primary treatment for prostate cancer. There can be mild incontinence for a few days when a catheter is removed or small amounts of urine can be lost as a result of stressful activities which increase abdominal pressure such as heavy lifting. This type of incontinence (Type 1) is usually time limited and can be eliminated by pelvic muscle exercises known as Kegel exercises. This is not uncommon with HIFU but is not a serious long term problem. More severe incontinence (Types 2 and 3) which requires long term use of incontinence pads and may be found after surgery or radiation treatment is very rarely a problem with primary treatment with HIFU.
Like other treatments (including surgery) there is not a 100% certainty that the nerves surrounding the prostate have been completely spared. Many patients experience temporary erectile difficulties after surgery, and it is not possible to predict what the final result might be for several months post treatment. The use of pharmaceutical agents at any time can assist with the quality of erectile function. Injured nerves may regenerate over time, but it may take up to one year to make a final assessment. Pharmaceuticals such as Viagra, Levitra, and Cialis assist with healing by increasing blood flow to the area.
Advantages of HIFU
- No blood loss
- Quick recovery
- Minimally invasive non-surgical procedure
- Radiation free
- An outpatient procedure
Disadvantages of HIFU
- No long term (20-30 years) outcome data
- Potential risk of impotence
- Potential risk of incontinence
- Not yet approved by the FDA for use in the U.S.
There are far fewer contraindications for HIFU than for other prostate cancer treatments. In fact, HIFU may be an excellent alternative for a patient who is contra-indicated for traditional surgery due to the presence of risk factors (cardio-vascular illness, excess weight, age, etc.). Patients who are diabetic can also be treated with HIFU. Anyone who is an insulin dependent diabetic is routinely treated as the first case of the day. The contraindications are limited to patients who are suffering from cancer at a more advanced stage than T2c and for whom the illness is no longer confined to the prostate. However, this contraindication is not linked to any risk to the patient, but rather to a lower healing potential.
An additional benefit of HIFU is that patients with a cardiac history that would not be a candidate for surgery can still qualify for HIFU. Patients with a history of cardiac problems will be asked to provide a cardiologist consult prior to treatment. Each patient’s history is assessed by our anesthesiologist on a case by case basis. All patients need to forward blood work and an electrocardiogram in advance of treatment.
HIFU has been performed in Japan and Europe for many years and just received FDA approval for use in the United States.