Australia’s universal bowel cancer screening program should be ditched in favour of a selective risk-based approach to testing, according to a panel of international experts.
Calling for a ‘seismic shift’ in bowel cancer screening approaches they say the evidence for benefits from universal testing is weak, and the harms and low participation rates suggest that resources would be better targeted at higher risk individuals to make informed choices.
Writing in the BMJ they say their evaluation of the balance of benefits and harms of testing found that routine testing should only be recommended for people with a bowel cancer risk of 3% or more in the next 15 years.
The panel was led by researchers from Norway and included gastroenterologists, nurses, patients and methodologists. They developed their recommendations using GRADE evidence-rating based on a systematic review of colorectal cancer screening trials and – in the absence of randomised controlled trials of FIT-based screening – microsimulation modelling.
They concluded that the evidence for two-yearly faecal immunochemical testing (FIT) showed only small and uncertain benefits for people at average risk – typically those with a 1-2% risk of bowel cancer over 15 years.
Also, the modest potential benefits must be weighed against the risk of harms from testing (e.g. bowel perforations with colonoscopy, unnecessary treatment) and quality of life (e.g. anxiety, burden of procedure), as well as a person’s values, preferences, and life expectancy.
They therefore recommended a “risk based approach” with no screening for men and women with an estimated 15-year bowel cancer risk below 3%.
For those with risk above 3%, threshold they suggest screening is offered by either FIT, colonoscopy or sigmoidoscopy after discussion of patient preferences such as wanting to avoid an invasive test or preferring a more certain method.
In a linked commentary Professor Philippe Autier at the International Prevention Research Institute (iPRI) in Lyon, France, said it was time to rethink the traditional public health approach to bowel cancer screening based on maximising uptake rates for universal testing.
He said the low participation rates seen in real world screening programs showed the importance of taking into account individual preferences and values in decision making.
And since the evidence for colorectal cancer screening was still “fragile”, personalised decision making could be based on individual risk, he suggested.
“A risk based approach is increasingly regarded as the most appropriate way to discuss cancer screening with individuals [and] may work particularly well for people who would otherwise remain refractory to screening,” he wrote.
Professor Autier added that there was still a great deal of uncertainty in evidence cancer mortality risks and screening participation , saying: “better knowledge of risk factors associated with late stage at diagnosis and colorectal cancer death is likely to improve risk based approaches.”