Freezing gives cancer breakthrough

Published on Saturday 10 October 2009 19:59

SURGEONS in Scotland are defeating cancer by freezing malignant tumours in a pioneering technique that has achieved remarkable results in patients who have failed to respond to radiotherapy.

New hope has been offered to prostate cancer sufferers by the procedure, which involves inserting "ice probes" into the body, which then shatter cancerous cells – basically killing them by giving them frostbite.

Although the treatment, known as "cryotherapy", is still in its infancy, it is causing great excitement among cancer specialists, who claim it could offer a potential cure for many common cancers.

Cryotherapy has only just been introduced to Scotland, but so far all those who have been treated have responded positively, and doctors are hopeful that the technique will be developed to treat liver and kidney tumours.

Early results indicate that the technique has successfully wiped out cancerous cells in prostate patients who have developed inoperable tumours that have also proved resistant to radiotherapy.

The technique has been used on 13 men in Scotland. They were all patients who were at risk of their cancer spreading from the prostate within five years – a development that would inevitably have led to premature death.

Follow-up tests suggest that the treatment has yielded excellent results.

All the patients treated have achieved an "undetectable" level of PSA (prostate specific antigen) – a substance that is produced by the prostate and is used by doctors as a marker for the presence of cancer.

High levels of PSA suggest that a man may have developed the disease.

The results are so encouraging that the service run by Gartnavel General Hospital and the Beatson West of Scotland Cancer Centre is now ready to treat patients from across Scotland.

The newly formed Scottish Prostate Cryotherapy Service is also liaising with other cryotherapy centres in Europe and the US to take part in a large-scale trial.

"I think they are most encouraging results," said Professor Hing Leung, a surgeon originally from Hong Kong who is pioneering cryotherapy in Glasgow.

"With time, we are hopeful that this treatment will make patients live longer. This is what we are talking about – a potential cure second time round."

Leung explained that the treatment is only currently offered to patients who had undergone radiotherapy, but had suffered a relapse. Those patients, he said, had a "very high risk" of the cancer spreading.

The service has been given around 250,000 from the Scottish Government's NHS budget and it is hoped that up to 50 patients will be treated each year. Around 2,000 Scottish men are diagnosed with the cancer and around 800 die from it annually.

Before they undergo the procedure, which lasts around two hours, patients are advised that there is a risk of side-effects – the two most common being problems urinating and impotence. Under general anaesthetic, the patient is brought into theatre, where a surgeon inserts between six and eight needles, or ice probes, into the prostate – a walnut-sized gland next to the bladder.

A catheter is put in the urethra, which runs through the prostate. Warm fluid is passed through the catheter to protect the urethra from the freezing process. Needles with thermometers and warming needles are also inserted nearby to ensure that delicate surrounding tissues and organs are not damaged.

The ice probes contain argon gas, which brings the temperature of the needle down to minus 40C rapidly. The swift drop in temperature causes water in the cells to crystallise, expand and shatter. The prostate is then left to thaw naturally and the procedure is repeated to ensure that the tumour has been destroyed.

One of Leung's first patients was Patrick Smith, a retired professor of mathematics. Smith was 61 and working at Glasgow University when he was told that he had prostate cancer in 2004.

Surgery was not advisable, because the tumour was right on the edge of the gland – meaning there was a risk that the cancer had already spread even if the prostate was removed.

Radiotherapy was the only option. After 37 sessions over seven-and-a-half weeks, he assumed that the disease had been defeated. But at the end of last year, Smith's PSA count started rising again and another biopsy confirmed the disease had returned.

"That was a shock, because you assume that you have your radiotherapy and that's it fixed," Smith said.

In March, Smith, now 66, was given cryotherapy and since then his PSA level has been "undetectable".

"These people really think they've got something here," Smith said. "They may be too modest to say so, but I think they feel this is something that is really going to produce results."