A drug made from tree bark is being combined with radiation therapy to cure cancer, experts revealed yesterday.
The ‘double whammy’ has proved 85 per cent effective in laboratory trials.
Last night the treatment was being hailed as a breakthrough in the battle against the disease which kills 133,000 Britons every year.
British experts who made the discovery are already talking of a ‘long-term cure’ for many common types of cancer after seeing astonishing results in a laboratory experiment involving human tumours grown in mice.
The dual treatment could be available to patients within five years.
Dr Barbara Pedley of the Cancer Research Campaign said last night: ‘We are excited by these results. Our trial shows that the combination can give a complete cure.’
The tests covered all the major forms of cancer which produce solid tumours, including bowel, breast, liver and lung.
The drug, called combretastatin, works by destroying the developing blood vessels which tumours generate to supply themselves. Used on its own, however, it leaves a ‘rim’ of cancerous cells at the edge, allowing the disease to return.
Radiation therapy completes the attack on the tumour by ensuring all the leftover cells are killed off. Antibodies with radioactive ‘warheads’ home in on the disease cells and destroy them.
The advance is part of a new generation of ‘targeted’ cancer therapies. Combretastatin, which is derived from the bark of an African bush willow, leaves normal blood vessels untouched.
The dramatic success story came in a study by the Royal Free Hospital and University College Medical School in London, and the Gray Laboratory Cancer Research Trust. The results were published in the journal Cancer Research.
The scientists found that human tumours grown in mice disappeared completely in 85 per cent of cases. The animals were still free of the disease almost a year afterwards.
Dr Pedley, head of tumour biology at the CRC’s targeting and imaging group at the Royal Free Hospital, said: ‘This combination can produce long-term cures.
‘Although we have been mainly looking at colorectal cancer, it works on a very wide range of cancers – all the solid tumours – which includes breast cancer.’
She said scientists believed the outer tumour cells may rely on the body’s normal blood vessels, which is why combretastatin could not kill them.
Experts now hope to start human trials of the combination therapy as the next stage.
Worldwide tests are expected to begin next year. About 200 patients with a variety of cancers would be recruited to centres in the UK and around the world.
If the trials achieve a similar success rate as those with the mice, they would pave the way for the treatment to become widely available, possibly within five years.
Dr Lesley Walker, director of cancer information at the Cancer Research Campaign, said: ‘This good news confirms what we have been saying all along –treatments that directly target cancers and spare normal tissue will be the therapies of the future.
‘As well as improving the effectiveness of treatment, this combination should greatly reduce side-effects.’
More than 220,000 people are diagnosed with cancer each year in Britain.
The latest findings back up early clinical trials involving 34 patients from London who experienced massive tumour shrinkage after taking combretastatin.
They were carried out by Professor Gordon Rustin, director of medical oncology at Mount Vernon Hospital in Middlesex.
He said yesterday: ‘The results from the trial in mice are very exciting because we are actually seeing a cure.’