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.”
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*”Inhibiting vascular endothelial growth factor receptor-2 signalling reduces tumour burden in the ApcMin/+ mouse model of early intestinal cancer”. Goodlad et al. Carcinogenesis, October 2006; 27: 2133 – 2139.
**AZD2171 is a potent and selective inhibitor of VEGF signalling and was developed by AstraZeneca – Wedge et al., 2005 Cancer Research. AZD2171: a highly potent, orally bioavailable, vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor for the treatment of cancer. Cancer Res. 2005 65(10):4389-400. AZD2171 is currently in Phase II and II/III clinical development in a wide range of tumours.
Bowel cancer is the third most common cancer in the UK, after breast and lung cancer. Almost 100 people are diagnosed with the disease every day. It affects similar numbers of men and women. When bowel cancer is found early, around nine out of 10 people can be cured.
Colonoscopy: A colonoscopy is an examination of the colon (large bowel) using a colonoscope. The colonoscope is a long thin bendy tube, which is put up into the colon through the anus. The tube is connected to an eyepiece which allows the doctor to see inside the bowel. The tube also has a slot that can be used to put special tools down, so that simple operations can be preformed through the colonoscope.
Symptoms of bowel cancer
If these symptoms last longer than four to six weeks, visit your doctor:
- Bleeding from the bottom with out any obvious reason
- A persistent change in bowel habit to looser or more frequent bowel motions
- Tummy pain, especially if severe
- A lump in your tummy
Screening for bowel cancer
Bowel screening aims to find cancers at an early stage when treatment is simpler and more effective. It can also find growths in the bowel, such as polyps, which are not cancer but can develop into cancer. Screening saves lives.
Gradually from 2006 onwards, men and women between 60 and 69 in England will be offered bowel screening every two years. The screening programme will be introduced in Scotland from 2007. Everybody who is registered with a doctor should have received their first invitation by 2009. Men and women who choose to be screened will be sent a screening kit so they can do the test at home.
About Cancer Research UK
Together with its partners and supporters, Cancer Research UK’s vision is to beat cancer.
- Cancer Research UK carries out world-class research to improve understanding of the disease and find out how to prevent, diagnose and treat different kinds of cancer.
- Cancer Research UK ensures that its findings are used to improve the lives of all cancer patients.
- Cancer Research UK helps people to understand cancer, the progress that is being made and the choices each person can make.
- Cancer Research UK works in partnership with others to achieve the greatest impact in the global fight against cancer.
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