A new bowel cancer screening test that can be done at home is 94 per cent accurate when compared with colonoscopies and has been submitted to the US Food and Drug Administration (FDA) for approval.
鈥淵ou just poop into a cup and then close the lid and ship it at ambient temperature to us,鈥� says , co-founder of US company Geneoscopy, which developed the test.
The best way to detect bowel cancer is with a colonoscopy, in which a tiny camera on a flexible tube is used to peer inside the colon and rectum. However, it is an expensive, invasive procedure.
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An alternative is the faecal immunochemical test (FIT). This looks for traces of blood in stools, which could be a sign of bowel cancer. In countries such as the UK and Australia, FIT kits are mailed to older adults so they can collect a sample of their stool at home and send it back for analysis. It is cheaper and more convenient than a colonoscopy, but less accurate.
Geneoscopy鈥檚 screening test works better than FIT because it looks for specific pieces of RNA, a molecule similar to DNA, that are only found in stool if they have been shed by bowel cancers, says Barnell.
, a gastroenterologist at Oregon Health & Science University and scientific advisor to Geneoscopy, presented the results of a large clinical trial of the test at the in Vancouver, on 24 October.
In the trial, the test was mailed to more than 14,000 adults aged 45 to 90 across the US who were recruited via social media. Stool samples that the participants collected at home and sent back were analysed using both a standard FIT and Geneoscopy鈥檚 new RNA test. To determine the accuracy of the at-home tests, the participants also had colonoscopies.
Pitted against the colonoscopies, the new test was 94 per cent accurate at detecting bowel cancers, compared with 78 per cent for the standard FIT. The participants who were found to have cancer mostly had early-stage cancers, which typically have a 鈥� if surgically removed.
The new test was also 46 per cent accurate at detecting advanced adenomas, clusters of cells on the verge of turning cancerous, compared with 29 per cent for the FIT. Being able to pick up advanced adenomas is important for prevention because if they are removed, 鈥渢he chance of getting cancer is nearly nothing,鈥� says Barnell.
Based on the promising trial results, Geneoscopy has submitted the test for FDA approval.
The new test could be used to replace the FIT in mass bowel cancer screening programmes, says Barnell. It is more expensive initially, but her modelling suggests it could be more cost-effective long term because the higher accuracy may allow more bowel cancers to be picked up at an early stage when they are cheaper and easier to treat, she says.
However, , a colorectal surgeon in Sydney and spokesperson for Bowel Cancer Australia, says the new test may be less appropriate for mass screening because only specialised laboratories can process RNA. In contrast, the FIT 鈥渋s already tested, validated, widely used and all labs can do it,鈥� she says.
Geneoscopy is now trying to make its screening test even better at detecting bowel cancers and advanced adenomas by looking for more types of tell-tale RNA in stools, says Barnell.
