High intensity focused ultrasound is the use of high frequency ultrasound waves to generate heat within an organ. It was originally developed as a means of treating benign prostatic obstruction. However, like other technologies for benign prostatic obstruction, such as lasers and microwaves, it did not prove either clinically or economically effective. Furthermore technical diffi culties related to the super heating of the rectal wall with the subsequent formation of an abnormal passage or fi stula between the prostate and the rectum. This problem has been largely solved by the incorporation in the Sonoblate machine of a sonachill device that cools the rectal wall and as such the fi stulation rate has decreased to only 1%. Whilst HIFU may still be regarded as clinically semi-experimental there is an increasing body of evidence followed for fi ve years indicating promising results with low morbidity.

The patient is anaesthetised and a HIFU probe is inserted through the anus and the prostate gland imaged. A very detailed planning study is performed that identifi es the relevant prostatic landmarks including the bladder neck, the sphincter mechanism and the neurovascular bundles carrying the nerves for erections. The planning is carefully performed such that the target area is defi ned by the prostatic capsule. The intention is to literally cook the prostatic tissue to one hundred degrees centigrade. Careful real time monitoring of the heating procedure is undertaken; excess heating is indicated ultrasonically by the “pop-corning effect”. This allows for careful regulation of the impact of the technology on the patient.

The Sonoblate 500 technology is in my opinion now the world leader in HIFU treatment as it allows for detailed planning with the ability to dynamically compare treatment sequences with planning sequences, this allows for the early detection of the pop-corning phenomenon.

The patient is discharged home with a catheter either the same day or the following day and the catheter is removed fi ve days later. Should the patient be unable to void a mini TURP procedure is performed to remove devitalised prostate tissue.

The patient considering HIFU needs to be carefully counselled and advised that of all the prostate cancer therapies available HIFU is the newest and the least evaluated in terms of long-term effi cacy. Nevertheless it is a very promising technology and patients are increasingly interested in investigating its application for themselves.

HIFU is particularly suited to men with early prostate cancer who are not comfortable with an active surveillance management approach. It is also suited to men with early prostate cancer who have signifi cant obstructive symptoms and who would for a variety of reasons be unsuitable for radical prostatectomy surgery. The advantage of HIFU in this group of men is that it has the ability to cure the prostate cancer whilst at the same time obliterating the transition zone to relieve obstructive symptoms.

Because HIFU is a heating and therefore entirely destructive technology it is potentially suitable for men with high Gleason score prostate cancers, for example Gleason scores 7-10. Unlike radiotherapy which is less effective the higher the Gleason score, the non-selective nature of HIFU destruction suggests that it will be effective against poorly differentiated prostate cancer cells. Further research and clinical trials are certainly necessary for determining the effectiveness of HIFU in this patient cohort.

HIFU is increasingly being applied to men who have undergone various forms of radiotherapy and whose prostate cancers have recurred. Such men cannot be further irradiated and salvage surgery for this group of patients is potentially a highly morbid procedure. In performing HIFU as a salvage therapy post radiotherapy it is very important that meticulous attention to rectal wall detail be undertaken in order to minimise the risk of prostato-rectal fi stulation.

My experience with HIFU in patients in Tokyo and in Sydney has at this stage been positive in terms of ease of treatment, length of stay in Hospital and minimal morbidity. Of course it remains to be seen whether HIFU beyond fi ve years is as effective as radical prostatectomy or prostatic brachytherapy. Japanese and European data to date suggests that this may well be the case.

The decision to treat or not to treat and the manner in which the patient is to be treated must be specifi cally tailored to the individual patient, his individual prostate cancer parameters and his co-morbidities.

Prostatectomy, iodine seed brachytherapy, high dose rate brachytherapy and now HIFU.