What is High Intensity Focused Ultrasound?
 
High intensity focused ultrasound, or HIFU, is a new type of cancer treatment. It is administered by directing a high frequency sound beam at a specific part of a cancerous tumor. HIFU was first proposed as a treatment for cancer over 50 years ago but it is only in the past few years that the medical establishment has been seriously investigating its use in treating different types of cancer. One advantage of this type of treatment is that it only uses sound waves to kill the cancer cells. This means that it doesn't have as many side effects as other types of cancer treatments already in use. Doctors hope to use HIFU to kill cancer cells without damaging healthy cells. Chinese researchers are the pioneers in using this treatment. They have done trials treating nearly 5,000 people with many different types of cancers. Researchers in Europe are now conducting trials to find out if HIFU can be used for people unable to have surgery to remove their cancer.

When Can HIFU be Used?

HIFU is only useful to treat a single tumor or part of a large tumor; it cannot be used to treat tumors that 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 cannot pass through solid bone or air, meaning that it is not suitable to treat every type of cancer. It has been used to treat some patients with pancreas, liver, and prostate cancers, and it has achieved quite encouraging results. It is becoming one of the safest and most effective approaches to control pancreatic tumors locally besides surgery, which is not a viable procedure for many pancreatic cancer patients. Combined with systematic therapies, HIFU has shown great potential for controlling pancreatic cancer and extending the survival of the patients, while inducing minimal side effects.

What Types of Cancer Might HIFU be Effective in Treating?

Below is a list of several types of cancers that HIFU has been tested on:

• Breast Cancer
• Pancreatic cancer
• Kidney cancer
• Prostate cancer
• Primary and secondary liver cancer
• Ovarian cancer
• Metastatic abdominal cancer

HIFU is not a suitable treatment for:

• Brain tumors
• Lung cancer and cancers in the pelvic area
• Skin cancers

Current Research and Treatment Options

Prostate Cancer

Since the prostate gland is located inside the pelvis, administering HIFU treatment is achieved by putting an ultrasound probe into the rectum. Doctors call these 'transected probes'. Results from trials so far show that HIFU may be as successful in treating prostate cancer as treatment with radical prostatectomy or radiotherapy. To date, comparative results to conventional therapies have not been obtained. In March 2005, NICE (The National Institute for Health and Clinical Excellence - UK) issued guidance for doctors on HIFU for prostate cancer, authorizing the use of this treatment, providing patients know:

1. What is involved in having the treatment
2. The side effects are not fully researched
3. The long term effects of HIFU are not fully researched

Two trials investigating the effects of HIFU on early stage prostate cancer are currently being carried out in the UK. The first, a clinical trial looking at HIFU for early stage prostate cancer, (Manchester) finished recruiting patients into a pilot study in July 2005. If the results are promising, they will go on to recruit more patients in a phase 2 trial. Another trial for prostate cancer is being done in Oxford and London. This trial finished recruiting patients in June 2006. This trial focused on patients who have cancer that is contained within the prostate, but who have not had any treatment before. Results are pending in both studies.

Kidney Cancer

There are two trials currently underway in the UK using HIFU for renal cell (kidney) cancer. In one trial, patients will have HIFU and a week or two later they will have an operation to remove their cancer. The doctors will observe the cancer cells to see what effect the HIFU has had. The other trial targets patients with more advanced cancers that cannot be removed with an operation. The aim of this trial is to find out how well HIFU works for kidney cancer, and what the side effects are.

Primary and Secondary Liver Cancer

There are two trials in the UK using HIFU to see what effect it has on liver cancer cells. They are conducted on two types of liver cancer: 1) cancer that started in the liver - primary liver cancer, or 2) cancer that has spread to the liver from another area of the body – secondary liver cancer or liver metastases. In one of the trials, patients are treated with HIFU and a week or two later they have an operation to remove their cancer. The doctors look at the cancer to see what effect the HIFU has had.  In the other trial, patients who have cancer that has spread to the liver and cannot be removed with an operation have HIFU treatment. The aim of this trial is to see how well HIFU works for secondary liver cancer, and to find out more about the side effects.

Pancreatic Cancer

Doctors in China have used HIFU to help relieve pain and other symptoms in people with advanced pancreatic cancer.  It is not being used to cure pancreatic cancer, but it can very safely control tumor growth. Both in the UK and China, surgery is still the first choice of treatment for people with pancreatic cancer that has not spread to other parts of the body. Since more than 80% of pancreatic cancer patients lose the chance of surgery when initially diagnosed and those that undergo surgery are subjecting themselves to one of the most complex surgical procedures in general surgery, HIFU has clear advantages over surgery in treating pancreatic cancer for its potential effectiveness and safety.

Bladder Cancer

Doctors in China have used HIFU to treat people with bladder cancer. Recurrent tumor appearance necessitates the use of surgery as the standard follow-up treatment.

Side Effects of HIFU

People who have been treated with HIFU so far have had very few side effects. It may cause some pain for 3 to 4 days afterwards. In rare cases, there are complaints of sore skin in the area treated.

Thus far, Chinese medical institutions mainly use HIFU to treat pancreatic, metastatic colorectal, liver, and ovarian cancers. In clinical trials carried out in China, HIFU displays the ability to destroy the cancer cell and reduce the tumor size, and even destroy the whole tumor when it is less than 3 cm in diameter. In Chinese treatment regimens, HIFU is combined with unique systematic cancer therapy in the targeting of pancreatic cancer.

References

1. Therapeutic Effect of High-Intensity Focused ultrasound to Treat 115 Cases of Primary or Metastatic Carcinoma of liver, NIU Li, CHU Yumin, et al., Chinese Modern Medical & Clinical，2005, 2: 14-15 

2. A Clincical Study of Thermotherapy of HIFU in Combination with Chemotherapy in Treatment of Advanced Pancreatic Cancer, GAO Yuan, FENG Jun, et al., Suzhou University Journal of Medical Science, 2006, 26: 428-30 

3. A Clinical Study on High Intensity Focused Ultrasound Treating 17 Cases with Advanced Pancreatic Carcinoma, YE Xinmin, ZHOU Chenhua, et al., J Med Res, 2007, 36: 114-16 

4. Clinical Study of Treating Advanced Pancreatic Carcinoma by High Intensity Focused Ultrasound, Military Medical Journal of South China, 2004: 18: 17-18 

5. The Efficacy of High-Intensity Focused Ultrasound (HIFU) in Advanced Pancreatic Cancer, Bo Xie, Jiajun LIANG, et al., Clin Oncol Cancer Res, 2008, 5: 183-6  

6. Trealment of Unresectable Pancreatic Carcinoma by High Intensity Focused Ultrasoun, CAI Mao-huai, YANG Shu-cheng, et al., Chin J Med Ultrasoun, 2004, 1: 260-62