New research suggests the 10-year interval between colonoscopies for middle-aged people with low-risk of bowel cancer, that is recommended in many countries, could be extended in certain circumstances, and complemented with less invasive screening tests according to University of Melbourne researchers.
Currently, Australian guidelines recommend that low risk people aged 50-74 who have had a normal colonoscopy to follow-up a positive home test kit result, only need to skip their next scheduled home test kit and resume home test kits in four years.
The study, published in The Lancet Gastroenterology and Hepatology, reviewed the risk of patients aged between 50-65 years developing or dying from bowel cancer in the years following a normal colonoscopy.
The researchers studied cancer rates from 5.2 million people in Canada over a 23-year period.
Study senior author Professor Nancy Baxter from the University of Melbourne said the research highlights the need to continuously review and refine diagnostic tools in clinical settings, where some people may require less invasive screening tests or may be able to have longer intervals between tests.
Professor Baxter said in the Australian context, it was important to strike the right balance, as well as showing the need for a more nuanced approach to bowel cancer screening.
“Guidelines around the world generally recommend 10 years between colonoscopies after returning a normal result, but it’s still quite common that patients are recommended an even shorter interval,” Professor Baxter said.
“Up until now, we haven’t had a great idea of how long someone’s risk of colon cancer is after a colonoscopy as the procedure wasn’t common before the 1990s. The currently recommended 10-year follow-up after a normal colonoscopy was a “best guess” as we didn’t have long-term follow up data.
“We can glean from this research that having a colonoscopy and returning a normal result does put someone in a lower risk category for developing colorectal cancer compared to those who have not had colonoscopy, and they remain at low risk for an extended period of time.
“It’s possible that people who have returned normal colonoscopy results could be better screened in the future with less invasive tests, such as home testing kits, therefore reducing the burden for patients as well as the health care system.”
Professor Mark Jenkins, Chief Investigator of the Bowel Cancer Screening Alliance, welcomed the research and said it showed that there’s no “one size fits all approach” when it comes to bowel cancer screening.
“For people at low risk with no family history, we know that the home test kit from the National Bowel Cancer Screening Program is best. For people at elevated risk with a strong family history, for people with worrisome symptoms, and for people who have had a colonoscopy that found irregular results, we know that colonoscopies are an important and lifesaving tool,” he said.
“But this research shows that in some areas and for some low-risk people, we may be able to reduce the frequency of screening. This is all part of improving and better targeting services.”
Professor Jenkins said the screening program is a vital tool in detecting bowel cancer early, before any symptoms appear.
“The home test kit from the National Bowel Cancer Screening Program is a free, easy test you can do at home that can detect small traces of blood in faecal matter, which can be a sign of bowel cancer.”
Further information:
- Professor Baxter and Professor Jenkins are investigators of the Bowel Cancer Screening Alliance (BCSA), an Australia-wide multidisciplinary collaboration of leading experts focused on research to increase participation in the National Bowel Cancer Screening Program. The BCSA is funded by the National Health and Medical Research Council.
- Anyone who had undergone a previous colonoscopy or colorectal surgery, had family history of bowel cancer or experienced bowel disorders was excluded from the study.
- It was announced in the 2024-25 Federal Budget that Australians from age 45 would now be eligible to access the National Bowel Cancer Screening Program from July 1.