SCOTS scientists are breaking new ground in developing a new test to help predict the likelihood of developing colon cancer.
A new approach is being developed by the University of Aberdeen and NHS Tayside to identify whether non-cancerous growths found in the colon, known as polyps, are likely to progress into cancerous tumours.
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As well as helping to predict the probability that cancer will develop from polyps, this new technique will help clinicians make decisions about the most appropriate course of treatment for each individual patient’s needs.
Dr Janice Drew, Senior Research Fellow, of the University of Aberdeen’s Rowett Institute of Nutrition and Health led the research, published yesterday (Thur) in the journal PLOS ONE.
In collaboration with colleagues in NHS Tayside, Dr Drew developed the approach in response to a sizeable increase in individuals diagnosed with polyps since the introduction of routine bowel screening in Scotland in 2007. Polyps are often indicative of pre-cancerous processes occurring within the colon and may be a factor that increases the risk of developing colon cancer in the future. Most polyps can be easily removed and this often prevents future cancers developing, but the routine follow-up of individuals found to have polyps is a major challenge for the health service.
Colorectal cancer is the fourth most common cause of death from cancer, accounting for 8% of all cancer deaths and the majority of colorectal cancers arise from adenomatous polyps. Polyps emerge in the colon as a result of uncontrolled cell growth. In some, but not all of these cases, polyps then transform into cancerous tumours. Disruption in key cellular processes is one of the main causes of tumour growth. Such processes are controlled by sections of DNA called genes.
Dr Drew said: “Currently, polyp size and number are the only predictors for screened patients at risk of developing colon cancer in the future, but this is not a sensitive measure of future risk of cancer.
“In addition, although visual assessment of the polyps and the degree of variation from normal colon tissue is made by trained medical staff, there is still a degree of inter-observer variation. Consequently, large numbers of patients who may not develop a cancer still have to go through bowel screening to check for the presence of polyps or development of cancer.
“The development of an objective and effective test would have significant benefits in the fight against colon cancer.”
She added: “The approach that we have developed begins the development of such a test. We will design tests to target the genes that we discover are important in predicting future risk of developing cancer and determine how accurate and sensitive they are. This would not replace the visual observations and size measurements conducted by a pathologist, but would be used in combination as an aid by the pathologist to make a more objective and sensitive assessment of an individuals risk of developing colon cancer in the future.
“With further refinement it is hoped that this new technique can be used to develop further tests to help inform the best treatment strategy for each individual patient.”
Using this new technique, scientists found that genes show expression of markers associated with the development of cancer before the tissue itself is recognisable as cancerous. They also reported that in colon cancer the genes that are crucial to regulating cell growth in the colon are disrupted far earlier than they had previously thought.
The normal course of treatment once polyps have been identified in the colon is to remove them. Once removed, the size of the polyp, together with visual assessment of the tissue are used as indicators of the likelihood that cancer may develop.
Bowel cancer is the second most common cause of cancer death for both men and women with around 1,600 people dying of the disease in Scotland each year.
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