Study suggests that cancer drugs can cause tumours to spread
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A new study indicates that drugs which shrink cancer tumours may also make it easier for them to spread.
US scientists, whose work is reported in the journal Cancer Cell, claim that some advanced drugs such as Glivec and Sutent can make cancer cells more mobile.
This is because they wipe out a group of cells called pericytes, that provide structural support to blood vessels and act as 'gatekeepers' to pen in cancer.
As a result, tumours find it easier to metastasise, or spread around the body.
Tests on mice showed that both Glivec and Sutent decimated pericytes by 70 per cent, while metastasis rates tripled.
Although both of these drugs have been shown to significantly increase patient survival in trials, this research suggests that they might also help cancers to become more deadly, particularly as metastasis to vital organs is the main reason why people die of cancer.
The Daily Mail reports that lead researcher Professor Raghu Kalluri, from Harvard Medical School, said: "If you just looked at tumour growth, the results were good. But when you looked at the whole picture, inhibiting tumour vessels was not controlling cancer progression. The cancer was, in fact, spreading."
The researchers also found a five-fold percentage increase in oxygen-starved 'hypoxic' areas in tumours lacking pericytes.
This is significant because cancer cells respond to oxygen deprivation by launching genetic survival programmes, again making them more mobile.
After testing their theory on mice, the researchers then examined 130 human breast cancer samples.
They found links between samples with low numbers of pericytes in tumour blood vessel networks and the most deeply invasive cancers, distant cancer spread, and five and 10-year survival rates lower than 20 per cent.
As a result of their findings, Professor Kalluri now thinks that some aspects of cancer treatment should be studied more closely.
He says: "We must go back and audit the tumour and find out which cells play a protective role versus which cells promote growth and aggression. Not everything is black and white. There are some cells inside a tumour that are actually good in certain contexts."
Have you been treated with Gilvec or Sutent? Let us know below...
Click on the image below to find out how to reduce your risk of breast cancer...
- Drinking alcohol<p> Drinking alcohol elevates oestrogen levels, and studies have found that cancer risk increases with the amount of alcohol consumed. </p>
- Smoking<p> While studies haven't shown any direct link between smoking and increased risk of breast cancer, secondhand smoke may be linked to a higher incidence of breast cancer. Considering how harmful smoking is for other reasons, part of a healthy lifestyle involves stubbing out. </p>
- Birth control pills<p> Studies have shown that women taking birth control pills have a slightly elevated risk of developing breast cancer, which is also related to how many years you take the pill for and when you started. Evidence suggests that 10 or more years after women stop taking oral contraceptives, their risk of developing breast cancer returns to the same level as if they had never used birth control pills at all. </p>
- Exercise<p> Studies have found that exercise helps to reduce breast cancer risk. Combine regular exercise with a healthy diet and low intake of saturated fat and alcohol for maximum benefit.</p>
- Red meat and a high-fat diet<p> A diet low in saturated fats which restricts red meat and other animal fats and is rich in veg and whole grains is recommended. Some studies have found an increased risk between red meat and breast cancer. Synthetic hormones used in the meat are thought to be responsible.</p>
- Breasfeeding<p> Studies have suggested that breastfeeding may lower a woman's risk of breast cancer. It's unclear exactly why, but it is thought that women's oestrogen levels remain stable when breastfeeding since they do not ovulate as regularly.</p>
- Say 'no' to long-term HRT<p> Hormone replacement therapy (a combination of oestrogen and progesterone) - used to replace female hormones to treat symptoms of the menopause and prevent osteoporosis - has been linked to increased breast cancer risk. Oestrogen treatment alone, when used for less than 10 years, does not seem to elevate risk, however.</p>
- Being overweight/obese<p> Being overweight or obese is linked to higher rates of breast cancer, particularly in post-menopausal women. Excess abdominal fat is something to watch out for in particular since it raises oestrogen levels and a woman's lifetime oestrogen exposure is directly related to her breast cancer risk. </p>
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