Lung tumours could be reduced by the method

A treatment which uses extreme heat to tackle advanced lung tumours may be able to prolong the patients' lives.

Patients for whom every other available treatment had failed underwent the experimental technique - and most enjoyed some benefit.

For some this was simply a reduction in their cancer pain - but for others, the tumour growth was slowed down, or their main tumour wiped out completely.

Of the 12 patients who were treated at the Harvard Medical School in Boston, 10 are still alive, which doctors say is "encouraging".

Their study was presented at the annual meeting of the American Roentgen Ray Society, alongside similar research showing the technique is also effective against many kidney tumours.

The technique works by using a probe and a series of electrodes to pass an electrical current through the tumour cells.

This heats them up to more than 100 degrees centigrade, killing them, but minimising damage to surrounding healthy tissue.

In lung cancer, the procedure takes between 15 and 40 minutes.

Several scans

Patients undergo a series of scans to help doctors locate precisely where the tumours are in the lung.

Then either the tumour itself is attacked or surrounding nerves to alleviate cancer pain.

Dr Eric vanSonnenberg, who led the study, said: "In nine of the patients, our goal was to destroy or slow the growth of their tumours - we also treated three patients to relieve their pain."

Two years later, ten of the 12 are still alive, and Dr vanSonnenberg said: "This is very encouraging, since these patients were quite ill when we treated them."

Doctors at the Mayo Clinic in Minnesota used the technique to tackle kidney tumours.

They told the meeting they were able to destroy 50 out of 51 tumours in 32 patients.

None of the patients, they reported, had suffered a recurrence of their cancer in the relatively short period since their treatment.

Dr Michael Farrell, who led the research, said: "Our aim would be to preserve renal function and avoid dialysis.

"We are seeing an increase in the number of renal tumours, especially in elderly patients."