New biomarker aims at affordable bowel cancer test

Testing for the presence of bowel cancer is currently a somewhat messy process, which has led to many Australians over the age of 50 skipping the test, even though kits are posted free of charge when they turn 50, 55 and 65.

Now a discovery by Australian researchers working at the CSIRO and the Flinders Centre for Innovation in Cancer in collaboration with biotech Clinical Genomics raises the prospect of an affordable blood test for bowel cancer that could dramatically improve bowel cancer detection.

The team identified a number of genes that register identifiable changes in the blood of people with bowel cancer.

“One new gene identified was particularly sensitive to cancer,” said Dr Peter Molloy, from CSIRO’s Preventative Health Flagship. “This gene is called ‘colon adenocarcinoma hypermethylated’ or CAHM.

“In 120 blood samples we observed a high positivity for cancers (68%) while still being accurate in 97 per cent of normal patients. We have also shown that a three gene test including CAHM was able to detect cancer 76% of the time with a 93% accuracy in normal patients” Dr Molloy said.

The researchers are currently developing a new blood test for bowel cancer based on this discovery, which is being tested with patients from Australia, the United States and Europe.

The collaborative research team is hoping to attract interest from other clinicians and scientists around the world to help them further validate the new test.

Dr Lawrence LaPointe, CEO of Clinical Genomics, said they have shown a high detection rate for bowel cancer while also demonstrating a false positive rate of about 5 per cent in samples drawn from a high-risk population.

“These clinical trial results are highly promising but we need to go one step at a time. The next step is to seek help from other groups and researchers to cast the net more broadly to see what we can achieve with a larger number of tests drawn from a sample of the general population,” he said.

“There is still some time to go before a blood based test of this nature might be broadly available to a community but the technology is clearly worthy of broader, rigorous testing.

“Importantly, a simple blood test like this could significantly improve patient participation with bowel cancer screening programs,” Dr LaPointe said.

Earlier this month the federal government announced an extra $50 million to extend the current National Screening Program for people aged between 50 and 70 to offer free tests every five years for bowel cancer, with a vision to offering screening every two years.

The current screening programme has been plagued by low participation rates, despite tests being sent out free of charge. A study published in the Medical Journal of Australia on 7 May found that only 43 per cent of people aged between 56 and 88 in the Hunter region of New South Wales had taken the current faecal occult blood test.

The development of a new blood test could supplement the existing faecal occult blood test and provide a second tier of detection for bowel cancer.

Senior investigator, Professor Graeme Young, from the Flinders Centre for Innovation in Cancer at Flinders University in Adelaide, said the prevention of bowel cancer is a major public health priority in Australia and early detection is clearly the path to better outcomes in the future.

“One of the key questions is how a test like this might complement existing screening efforts in a cost-effective way to save even more lives in the future,” he said.

“The need now is to collaborate more broadly with national and international researchers committed to translation of science innovation to clinical outcomes, to help validate these exciting findings in large scale prospective studies,” Professor Young said.

The researchers presented their findings at the Digestive Disease Week 2012 conference in San Diego earlier today in a presentation called ‘Discovery and validation of a novel DNA methylation biomarker for colorectal cancer with application to blood testing’.