A new High Intensity Focused Ultrasound (HIFU) treatment has been announced for the treatment of prostate cancer. The procedure uses ultrasound to destroy deep-seated tissue without affecting the surrounding healthy tissue.
The manufacturers of the system, UKHIFU, claim the time for patient recovery after HIFU treatment is significantly less than other therapies like radical prostatectomy. Recovery involves wearing a simple self managed catheter for a short period of time after treatment, and patients typically return to a normal lifestyle almost immediately after the 2 - 3 hour procedure. It is very much a same-day or out patient programme. HIFU treatment can also be safely repeated if necessary, and even added as a therapy by those patients who have experienced recurrence after being treated with an alternative therapy such as radiation therapy, including brachytherapy and cryosurgery.
The Sonablate 500 system has approval in Europe for the treatment of prostate diseases (including prostate cancer, benign prostatic hyperplasia and prostatitis). There are currently 35 units being used in medical institutions around the world.
The HIFU therapy allows the clinician to get a live image of the prostate and cancerous tumor, then target and kill the tumor with a beam of clean ultrasound energy, which effectively destroys the cancerous tissue without affecting the surrounding healthy tissue. HIFU energy works like a magnifying glass and sunlight. Using a magnifying glass, you can focus energy of the sun and concentrate it over a focus point while allowing safe and harmless energy transfer over the entire course of that beam until it reaches the point of concentration.
The therapy uses an instrument called the Sonablate(R) 500. Using a probe inserted into the patient's rectum, ultrasonic beams are focused onto the cancerous region. Lesions are created side-by-side until the entire desired volume of the prostate is treated. HIFU has the potential to achieve this by virtue of the size of the target lesion that it creates, and works by focusing a pulse of high energy ultrasound waves onto single location about the size of a grain of rice.
The delivery of this energy to such a small area results in an increase in temperature to a point where the lipids (fats) in the cell membrane melt and the proteins denature. A reproducible but small volume of tissue destruction occurs. The distribution of these target lesions is under the control of the clinician. During the planning phase of the treatment, ultrasound is used to delineate the prostate in two dimensions. Targeting can be planned in order to avoid the urinary sphincter, rectum, and possibly the neurovascular bundles (as preservation of these may preserve erectile function). Once the treatment plan is established the treatment is both driven and monitored by a computer program within the HIFU delivery system.