Cancer Research UK scientists target early bowel cancer prevention with new drug

Scientists from Cancer Research UK’s London Research Institute have found that a new drug can reduce the number and size of pre-cancerous growths, or polyps, in the bowels of mice – which can progress to bowel cancer if left untreated, reveals a study published today (Friday) in Carcinogenesis*.

The researchers gave a drug called AZD2171** to mice genetically pre-disposed to developing pre-cancerous polyps in the bowel. All of the mice were treated with the drug for a period of 28 days. Half of the mice began receiving the drug at 6 weeks old, and the other half at 10 weeks – to examine the effects of early or late treatment.

In the early group, they found that the drug reduced the number and size of polyps in the small intestine and large bowel, while in the late group only the size of the polyps was reduced. If confirmed in studies in humans, these findings may prove to be an effective way of stopping bowel cancer developing in some patients.

Bowel cancer is one of the most common cancers – around 35,000 people in the UK are diagnosed with the disease each year – and it is the second biggest cause of cancer death. Most bowel cancers develop from pre-cancerous polyps that grow on the bowel wall. These polyps are fairly common and it is estimated that around 40 per cent of people over the age of 50 have them. However, only between 5 and 10 per cent of these polyps will go on to develop into cancer.

One way to prevent the development of bowel cancer is to remove these polyps. However, only people with a higher than average risk of developing the disease are specifically screened for these polyps. A national bowel cancer screening programme is now being rolled out for everybody aged between 60 and 69 yrs.

In order for polyps to grow and progress into cancer, they need to grow their own blood vessels – a process called angiogenesis. The drug AZD2171 interferes with a molecule called vascular endothelial growth factor (VEGF), which acts as the signal telling cells to grow new blood vessels. By disrupting the VEGF signalling, the drug can stop blood vessel formation and therefore restrict tumour growth.

Dr Robert Goodlad, who led the study at Cancer Research UK’s London Research Institute, said: “This initial work in mice may one day translate to man and could provide the basis for a pill to treat polyps and so prevent tumours. We have shown for the first time that it is possible to treat mice using a drug that targets this specific pathway.

“Early clinical trials of this drug in humans with advanced bowel cancer have found that it is well tolerated without serious side effects. Larger scale studies now have to be undertaken to see if the drug is effective.”

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: “These are very promising early findings and we look forward to seeing how the drug performs in patients. Anything that adds to our understanding of how to prevent bowel cancer is very important work because the disease is one of the most common cancers and causes around 1 in 10 of all cancer deaths.”

ENDS

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