Australia has one of the highest rates of bowel cancer in the world, so regular colonoscopies are recommended for people at higher risk.

A new study has found that screening for bowel cancer using at-home faecal immunochemical tests could help to reduce the frequency of colonoscopies for some of the above-average risk individuals, also confirming a low risk of advanced tumours following multiple negative tests.

“Due to the risks, costs and burden on the health care system from surveillance colonoscopies for bowel cancer, there is a need to explore how we can further personalise screening intervals,” says study lead author Dr Molla Wassie, an NHMRC Emerging Leadership Fellow in the Flinders Health and Medical Research Institute.

“While people at a high-risk are encouraged to undertake surveillance colonoscopies every one to five years depending on their family history and prior colonoscopy results, faecal immunochemical tests could be one way of identifying those who could extend their surveillance interval out further.”

Published in pre-print in the journal Clinical Gastroenterology and Hepatology, the team conducted a retrospective study of more than 3300 individuals enrolled in the Southern Cooperative Program for the Prevention of Colorectal Cancer (SCOOP), an SA-based bowel cancer surveillance program.

The study participants had no bowel cancer found at their previous colonoscopy and had been recommended to have another in 3 to 5 years, while also being sent a faecal immunochemical test annually.

“We found the risk of the follow-up colonoscopy identifying advanced neoplastic lesions including cancer following a negative FIT was around 1 in 10, with this risk decreasing further with every subsequent negative result, with the risk only 5.7 percent after four negative tests,” says Dr Wassie.

The authors say this supports the use of faecal immunochemical tests to further personalise an individual’s cancer surveillance interval and reduce the overall frequency of colonoscopies.

“Like any surgery, a colonoscopy can be invasive and carries risks for the patient. Add this to access issues, costs and the burden it places on our already strained healthcare system and there is a significant need to ensure current recommendations are suitable,” says Dr Wassie.

“In colonoscopy surveillance programs in Australia, intervals up to 10 years between colonoscopies have recently been suggested as a suitable timeframe for cancer surveillance after low-risk findings.

“Our study supports the introduction of annual at home faecal immunochemical tests to be incorporated into surveillance programs, but like any surveillance program, uptake and adherence to the surveillance schedule will be a key factor in its success.”

The test that we use in our research is the same one that is used in the Australian National Bowel Cancer Screening Program. It is a very simple test that involves collecting two very small samples of stool in tubes, then sending it to the laboratory in the post.

“We conducted this study to find out if we could use the home stool screening test to determine which individuals are at lower risk for bowel cancer, or pre-cancerous findings, to then hopefully be able to reduce how often they need colonoscopy,” explains co-author Associate Professor Erin Symonds, Team Leader of the Bowel Health Service at the Flinders Centre for Innovation in Cancer.

“This might be a way that we can safely reduce the burden on healthcare resources.”

The paper – ‘Multiple negative faecal immunochemical tests reduce risk of advanced neoplasia in a colonoscopy surveillance program’ (2023) by Molla M Wassie, Graeme P Young, Jean M Winter, Charles Cock, Peter Bampton, Mahadya Rahman, Richard Heddle, Robert Fraser, Rosie Meng and Erin L Symonds – will be published in the journal Clinical Gastroenterology and Hepatology. DOI 10.1016/j.cgh.2022.12.024

The research was supported by the Flinders Foundation, the Cancer Council SA’s Beat Cancer Project and in-kind support from Eiken Chemical Co Ltd (Japan) who provided the faecal immunochemical tests used in the study but had no input into the study design, data analysis, or preparation of the paper.