In a new study, researchers say routine testing for bowel cancer should not be recommended for everyone aged 50-79 years.
This is because, for those at very low risk, the benefit is small and uncertain and there are potential harms.
But they say screening should be recommended for men and women with a risk of 3% or more in the next 15 years.
This is the point at which the balance of benefits and harms tilts in favor of screening.
The research was conducted by a group of international experts.
The advice is based on the latest evidence and to produce rapid and trustworthy guidance based on new evidence to help doctors make better decisions with their patients.
Bowel (colorectal) cancer is a common type of cancer in men and women—about 1 in 20 people in most high income countries will get it during their lifetime.
A person’s risk depends on their age, sex, genetics and lifestyle factors, such as alcohol intake, smoking, physical activity and diet.
Most guidelines recommend screening for everyone from age 50, irrespective of their individual risk.
At this age, the risk of developing bowel cancer over the next 15 years is typically 1-2%, meaning that in a group of 100 people with the same risk factors, one or two will develop bowel cancer within the next 15 years.
The four most common screening options are home faecal testing (FIT) every year or every two years, sigmoidoscopy (examination of the lower colon) or colonoscopy (examination of the entire colon) done at a clinic or hospital.
Recently published research on the long term effects of bowel cancer screening has shed new light on the benefits and harms, and has the potential to change current recommendations.
So the team reviewed the evidence base, including this new evidence, to evaluate the benefit-to-harm balance of screening using a “risk-based approach.”
They took account of an individual’s cumulative risk of bowel cancer over the next 15 years together with the risk of harm from the procedure (e.g. bowel perforations, unnecessary treatment) and quality of life (e.g. anxiety, the burden of procedure), as well as a person’s values, preferences, and life expectancy.
Their recommendations apply to healthy individuals aged 50-79 years with a life expectancy of at least 15 years.
For men and women with an estimated 15-year bowel cancer risk below 3%, they suggest no screening and say most informed individuals in this group are likely to decline screening.
However, for men and women with an estimated 15-year bowel cancer risk above 3%, they suggest screening with one of the four options, and say most informed individuals in this group are likely to choose to screen after discussing the potential benefits and harms with their doctor.
The panel does not recommend anyone test over another, but they found convincing evidence that people’s values and preferences on whether to test and what test to have varies considerably.
The authors stress that there are still many uncertainties in terms of what is the most effective screening test or combination of tests, and at what age and interval they should be used, and suggest this should be the focus of future research.
These recommendations may also be altered as new evidence emerges.
The study is published in The BMJ.
Copyright © 2019 Knowridge Science Report. All rights reserved.
