Why are screening colonoscopy recommendations different across countries?
If you live in the US and are nearing middle age, you’ll probably hear a lot about the importance of getting a colonoscopy. From colorectal cancer awareness month to celebrities filming their colonoscopies, there’s a lot of pressure for Americans in their 40s and 50s to get the “gold standard” of screening.
Because of this emphasis on colonoscopy, Americans may be surprised to learn that other countries consider routine colonoscopy screening for cancer to be overuse. In Australia and Ontario, Canada, for example, medical societies recommend screening using less invasive tools like a FIT test or FOTB first, and only doing a subsequent colonoscopy if the results are positive.
What explains this discrepancy in screening guidelines ? In a recent editorial in BMJ Quality and Safety, Kelsey Chalmers, Shannon Brownlee, and Vikas Saini of the Lown Institute explore why routine colonoscopy is recommended in the US as a first-line screening method, but not in other countries.
“The contrast between US standards for colorectal cancer screening and those of other countries provides insight into different nations’ consideration of costs and outcomes.”Chalmers, Brownlee, and Saini, BMJ Quality & Safety 2023
A key issue is the lack of high-quality evidence demonstrating the superiority of colonoscopy compared to other screening methods. Although colonoscopy has the benefit of being a more sensitive measure and allows for the ability to remove polyps, the onerous preparation requirements and higher risk of complications compared to other screening methods may counteract the benefits. For example, the recent NORDICC randomized trial of colonoscopy screening in Europe found no evidence that participants invited for colonoscopy had improved mortality compared with a control group without screening, in large part due to low take-up from the invited group.
Without good evidence that colonoscopy is better than other types of screening, the values and priorities of policymakers in each country play a larger role in crafting recommendations. One of these most important priorities is cost. Colonoscopy is by far the highest-cost screening method for colon cancer, so it makes sense that other screening methods are preferred in countries that care about keeping healthcare costs low.
“Countries with limited healthcare resources or single-payer systems may be readier than the USA to define overuse based on the societal harms of delivering high-cost, high- profit care to some, while others go without beneficial care.”Chalmers, Brownlee, and Saini, BMJ Quality & Safety 2023
Although the US is an outlier when it comes to healthcare costs, these costs are fragmented between governments, employers, insurance companies, and patients. That makes reducing low-value care a much harder sell to patients, because the cost savings don’t necessarily go into their pockets. In fact, until fairly recently, patients were charged out of pocket to get a colonoscopy after a positive screening result, creating a disincentive for going the route recommended in other countries.
Overuse still widespread
However, even in the US where colonoscopy is recommended for screening, there is still substantial overuse. Previous research on colonoscopy estimates that 17-25% of screening colonoscopies are done on patients at ages above or below national guidelines, costing $3 billion per year.
In BMJ Quality and Safety this week, researchers at the VA Ann Arbor Center for Clinical Management Research share how they developed a new metric to identify screening colonoscopy overuse using ICD-10 diagnostic codes. They applied this metric to data from the Veteran’s Affairs health system and found that 24.5% of screening colonoscopies met the criteria for probable or possible overuse.
This new metric will be incredibly useful for American researchers to identify colonoscopy overuse nationwide (keep an eye out for colonoscopy overuse in the Lown Hospitals Index soon!)