WHAT IS HIFU?
HIFU, which is short for High Intensity Focused Ultrasound, is the focusing of high intensity sound waves to create heat at a specific point, called the focal point. With state-of-the-art technology, HIFU can be used to destroy targeted tissue during a procedure that is individually customized for each patient’s prostate cancer treatment. When HIFU energy is delivered to a specific location within the body, the tissue temperature at the focal point is elevated to nearly 195 degrees Fahrenheit in a matter of seconds, resulting in tissue destruction, while the tissue outside the focal point remains unharmed.
HIFU is a revolutionary form of treatment for organ-confined disease that allows treatment of prostate cancer without radiation and without having to make a surgrical incision in the body.
HOW DOES HIFU WORK?
The HIFU technique consists of the release of energy through an endorectal probe. The ultrasound waves travel through the rectum walls without causing any damage to the tissue, which are instead focused on the prostate.
In order to understand the basic concept of how HIFU works an analogy can be drawn between HIFU burning prostate tissue and sun rays entering a magnifying glass to burn a leaf. When a magnifying glass is held above a leaf in the correct position on a sunny day the sun’s rays intersect below the lens and cause the leaf to burn at the point of intersection.
If you insert your hand into the path of either one of the sun’s rays individually, away from the point of intersection, there is no significant heat felt or harm caused. Alternatively, if you place your hand at the point of intersection you will be burned.
The scientific principles at work in this example are the same as those with HIFU. Instead of light as the energy source, HIFU utilizes sound. Instead of a magnifying glass, HIFU uses a transducer. Just as the individual ray does not burn the hand, the individual sound wave does not burn the tissue it travels through.
ADVANTAGES OF THE USE OF HIFU OVER CONVENTIONAL TREATMENTS
The use of HIFU carries in itself many advantages over traditional procedures to treat prostate cancer. Perhaps the most important one is the lack of a surgical procedure, so blood loss is minimal. Furthermore, the use of HIFU does not involve radiation and it is non-ionizing. This means that the treatment can be performed several times, or can be used as a rescue treatment when all other techniques have proved themselves ineffective. The HIFU procedure does not require a prolonged stay in the hospital or recovery period; in fact, in can be preformed as an ambulatory technique and does not require the use of anesthetics.
The ultrasound waves travel harmlessly through the tissue that surrounds the prostate gland. According to International HIFU, an organization that leads the research about this treatment, this fact reduces the risks of side effects common to conventional procedures in use today for prostate cancer, such as impotence and incontinence.
TREATMENT AND FOCAL THERAPY
Focal therapy is the term used the treatment seeks the destruction of the tumoral mass with a significantly low margin of surrounding tissue. Such therapies offer the patient the potencial to combine oncological control and minimal side effects. the standard therapy includes active surveillance or radical treatment. None of these options are ideal. active surveillance brings with it the risk of under-treatment, psycological morbility as a direct result of anxiety, and it is not exempt from collateral damage due to the repetitive biopsias. Even though the radical treatment is the most used nowadays when seeking a cure, it does involve high risk of over-treating due to its many side effects and collateral damage.
With the rise of unifocal and unilateral proportion of cancers among low-risk males, a focal approach could potentially avoid both under and over-treatment. With the improvement in the precision to localize cancer brought by multiparametric nuclear magnetic resonance and the new biopsy strategies like transperineal mapping biopsy, ablative techniques like cryotherapy, high intensity focus ultrasound (HIFU), photodynamic therapy and radiointerstitial tumor ablation all make of focal therapy not a probability but a reality.
RESULTS OF THE USE OF HIFU
Due to the precision and flexibility of the HIFU technique, patients can decide together with their doctors on a personalized treatment specifically engineered to their particular prostate cancer diagnosis.
The standard Sonablate procedure completely destroys the prostatic gland. This procedure is the most appropriate option for patients that present prostate cancer confined to the organ, which does not limit to a discrete section of the prostate.
The clinical results of a standard HIFU procedure are:
- 92% of patients were treated satisfactorily
- More than 99% of patients retain urinary continence.
- 70% of men treated maintain erectile function.
Focal HIFU is an emerging technique for the treatment of prostate cancer, in which only the tumor is treated, instead of the entire prostatic gland. Local HIFU increases the possibility to maintain important structures that surround the prostate entirely free of damage, which considerably reduces side effects. It can be ideal for mean in risk of lower and/or intermediate cancer, which happen to have a tumor inside the prostate or several tumors in the same side of the gland. Focal HIFU allows the procedure to be even shorter, generally between 20 to 90 minutes, and a faster comeback to everyday life.
Clinical results of focal HIFU procedures are:
- 95% of men treated retained potency (defined as erections sufficiently strong for penetrative sex).
- 89% of men treated reached the TRIFECTA state (defined as diaper and incontinence free, with sufficient erections for penetration and cancer control after 12 months of undergoing the procedure).
Clinicians can determine if a patient is a candidate for either the standard or focal Sonablate HIFU procedure.
an important fact is that the Sonablate HIFU can be used in patients that have been previously treated for prostate cancer, where the cancer has returned, whish is commonly known as Rescue Treatment. This procedure can be performed on patients previously treated with Radical Prostatectomy, radiation, cryotherapy or a previous HIFU procedure.