HIFU is a very recent addition in the armour of the medical world for cancer treatment. Though HIFU has proven to be quite effective for prostrate cancer, but for other types of cancer the clinical trials are still on, finds out Sonal Vij

High Intensity Focussed Ultrasound (HIFU) is the latest precise medical procedure available that utilises the power of ultrasound waves to destroy deep-seated cancer tissue with pinpoint accuracy for treatment. It is a state-of-the-art acoustic ablation technique.

Explains Dr Ramesh Ramayya, Chairman and CEO, Dr Ramayyas Urology Nephrology Institute and Hospitals, Pramila Hospital, Hyderabad, "HIFU focuses sound waves in a targeted area which rapidly increases the temperature in the focal zone— thus destroying the tissue. This induces hyperthermia wherein the temperature goes up to 100o C." This is a one-to-four hour one-time procedure which is performed under regional anaesthesia.

Generally, HIFU is used for small tumours. Shares Senior Consultant from Primus Super Specialty Hospital, Dr SK Pal, who also conducted the first HIFU surgery in Delhi, "This is useful only to treat a single tumour or part of a large tumour. Since the range is limited, it cannot be used in case the tumours are more widespread. This means that HIFU is not suitable for people with cancer that has spread to more than one place in their body. HIFU doesn't pass through either solid bone or air." This also means that it is not suitable to treat every type of cancer.

As it destroys the diseased tissue non-invasively, it is also known as non-invasive HIFU surgery. The procedure is robotic with hardly any manual intervention. Says Dr Ramayya, "The entire therapeutic treatment is done by moving the applicator on its robotic arm in order to juxtapose multiple shots, according to the protocol designed by the physician." This technology can achieve precise ablation of diseased tissue, and thus it is called 'HIFU surgery'. Continuously updated real-time images are referred to, by the physician. These images are used to map out and execute the entire treatment plan. The physician can see the progression of the treatment and customise it, if required.

HIFU is a new procedure and there is a lack of documented data available and that is why it is not recommended for younger patients. Right now, the documented data is available only for 10 years. As the documented data increases, more and more younger patients will be recommended for the usage of HIFU.

Remember the game that we as kids used to play trying to focus the sun rays at one point through a magnifying glass? Well, to understand how HIFU works, an analogy can easily be drawn between HIFU ablating/ destroying the prostate and sunrays entering a magnifying glass to burn a paper. When a magnifying glass is held above the paper in correct position on a sunny day, the sunrays intersect below the lens. This causes the paper to burn at the point of intersection.

Similarly, says Dr Mahesh Desai, Chairman, Department of Urology, Muljibhai Patel Urological Hospital (MPUH), Nadiad (Gujarat), "If you insert your hand into the path of either one of the sun rays individually, away from the point of intersection, there is no significant heat felt or harm caused. But, if you place your hand at the point of intersection ,your hand will burn." The scientific principles at work in this example are the same as those with HIFU. The only difference between the two is that instead of light as the energy source, HIFU makes use of sound. Instead of a magnifying glass, HIFU makes use of a transducer. Just as the individual sunray is harmless to the hand, individual sound wave is harmless to the healthy tissue it travels through.

In India, HIFU is a new technique mainly used for the treatment of prostrate cancer. Dr Narmada P Gupta, Professor and Head Department of Urology, AIIMS, New Delhi shares that so far, there have been nearly 12 such surgeries to treat prostrate cancer conducted pan India. Explaining the methodology, he says, "Because the prostate is situated deep within the pelvis, HIFU for prostate cancer is conducted by putting an ultrasound probe into the patients' rectum. From that position, the ultrasound can direct beams more accurately at the prostate."

For the management of localised cancer of the prostrate, other treatment options are radical prostatectomy (which can be done either done using laproscopically or robotic), radiotherapy which can be conducted using external beams (IMRT) and brachytherapy.

The acceptance for HIFU as a treatment option for prostrate cancer is picking up, but effectiveness from this treatment is yet to be fully proven. Dr Pal explains, "Results from trials so far show that HIFU may be as successful in treating prostate cancer as the other treatments with radical prostatectomy or radiotherapy. But, we also need to know that the long term results will be as good as surgery or radiotherapy. The treatment hasn't been around long enough for us to know that yet." This treatment is still to be approved by the FDA. Clinical trials are still on in the UK, Japan and China.

HIFU has also been quite successfully used against uterine fibroids. HIFU treatment for uterine fibroids has been approved by the FDA in October 2004. As far as India goes, a few hospitals in Mumbai are conducting this surgery. BEAMS fibroid centre at Khar, Mumbai is one of the few centres which uses HIFU to treat uterine fibroids.

Experts consider HIFU as a promising technology. The USP of the treatment is that it is minimally invasive; in-depth as well it generates precise tissue necrosis. There is no effect on the surrounding areas. Dr Desai says, "The transducer has a coolant which keeps the surrounding areas cool and prevents any injury."

There is an advantage of repetition of the treatment. Dr K V Ramana Murthy, Clinical Applications expert, Healthware, says, "In case the cancer re-appears, this treatment can be repeated. It can also be used after brachytherapy as well as radiotherapy, but one has to be very careful about the rectum wall."

HIFU can also be administered to older patients as well. "When patients in their 70s are diagnosed with prostrate cancer, this is the only technique we recommend. It is also recommended for young patients who suffer from high blood pressure, diabetes and cardiac diseases," shares Dr Desai.

Explaining the advantages, Dr Ramana Murthy adds, "The use of HIFU is quite effective showing no sign of cancer in biopsies taken following the procedure. The levels of PSA drop dramatically after the treatment." He adds that in general cases, no hormones are required. Also, people who have been treated with HIFU so far have had very few side effects.

One of the possible side-effects of HIFU may be difficulty in urine retention or in passing water (this is often overcome by temporary use of a catheter). However, conducting a little bit of the prostrate reception has solved this problem. Also, impotence occurs in around 50 to 70 per cent of patients. Dr Ramana Murthy says, "There is an option to spare the nerves for a unilateral positive cancer. In some cases, there are infections of the urinary tract and bleeding and incontinence may also occur."

HIFU may cause some pain for three to four days post surgery. In some cases, HIFU also causes sore skin in the area treated.

The cost of the machine is around Rs four crore. As of now, in India the only centre that owns the HIFU machine is Gujarat-based Muljibhai Patel Urological Hospital. The other centres like Delhi-based Primus Hospital and Hyderabad-based Dr Ramayyas Urology Nephrology Institute and Hospitals, Pramila Hospital rent the machine from companies per surgery. Dr Pal shares that the rent per case is around Rs two lakh. No wonder that a patient pays between Rs 3.5-4 lakh!

Delhi-based AIIMS too conducted HIFU for a patient with prostrate cancer during a workshop. However, Dr Gupta reveals that AIIMS will continue to use robotic radical prostatectomy as the first choice. As of now, there are no plans to buy HIFU. "In the entire world, 85 per cent radical prostatectomies are done using robotic assistance. The complete gland along with cancer is removed. However, in case of radiotherapy and HIFU, the tumour can be controlled but cannot be completely removed. It can also lead to re-occurrence of the tumour," he explains.

Though HIFU seems a much promising technology. it will take a much longer time to gain popularity.