Alan Cassels, who is a journalist and pharmaceutical policy researcher at the University of Victoria, British Columbia, reflects on the differences between Canadian and US guidelines on colon cancer screening and why that disparity isn’t being reported on.
Do borders really exist in medicine, where the mere act of crossing political boundaries changes what screening programs are recommended? It seems that they do exist, and they’re well guarded.
Generating numerous headlines in major Canadian papers such as the National Post, The Toronto Star, Globe and Mail and Reuters, the Canadian Task Force on Preventive Health Care came out this week with new recommendations on colon cancer screening, essentially saying that routine colonoscopies were not justified. By contrast, in the United States, the U.S. Preventive Services Task Force (USPSTF) 2015 guidelines say that adults aged 50–75, should have a colonoscopy every 10 years; FIT (fecal immunochemical testing) or gFOBT (guaiac fecal occult blood testing ) annually or flexible sigmoidoscopy every 10 years plus FIT annually.
For this age group the Canadian Task Force says there is insufficient evidence to justify using colonoscopy for routine screening for colorectal cancer. They recommend patients should undergo the fecal occult blood testing every two years or flexible sigmoidoscopy – a procedure which examines the lower part of the colon and rectum every 10 years. These colon cancer screening guidelines, published in the Canadian Medical Association Journal, are for low-risk people: asymptomatic adults, aged 50 to 74 who have no prior history of the disease, no family history or symptoms such as blood in the stool, or a genetic disposition to the disease.
Despite the significant gulf that separates the Canadian and US recommendations, only a smattering of US news outlets, such as US News and World Report, ventured to cover the new Canadian guidelines.
Why the difference? How can there be such a wide disparity, on an issue with huge patient care and financial ramifications, that goes almost totally unreported on?
Perhaps what happens in medicine in Canada isn’t necessarily big news in the US. Americans have been told ad nauseum that colonoscopy screening is the “gold standard” and that you’d be a fool not to get one. So the fact that Canadians won’t pay for the procedure is their problem — and one that Americans needn’t dwell on. But not everyone in the U.S. thinks this way. HealthNewsReview.org, for one, has weighed into this debate frequently and vigorously, noting that colon cancer screening news coverage is ‘all over the map,’ with too much unbalanced reporting on the issue. (For a full course meal on US colonoscopy screening journalism, search the HealthNewsReview,org site with the keyword ‘colonoscopy’ where you’ll find nearly 50 related stories and blogs).
Our national differences in screening recommendations aren’t a reflection of the amount of knowledge each country’s teams of screening experts have, but rather an array of scientific, economic and possibly cultural issues that lay behind those recommendations.
For some perspective I spoke to Dr. Maria Bacchus, chair of the Canadian Task Force on Preventive Health Care (Canada’s equivalent to the USPSTF) working group on colorectcal cancer, an independent body of 14 primary care and prevention experts who develop clinical practice guidelines. For Dr. Bacchus colonoscopies have an important role to play in investigating symptoms and follow up, but she said there isn’t enough evidence to suggest they should be used as a first-line screening tool.
“When we looked at all the evidence, all the randomized controlled trials we wanted to see how it compared to other tests in terms of reducing colon cancer mortality.” There are currently four randomized trials in process and when they report back (which may be up to five or ten years away) “we will have to look at other things.”
As for the difference between Canada’s and the US’s recommendations, she said that the USPSTF would have included observational studies in their analysis of colonoscopy screening while the Canadians did not. She said: “We found good RCT [randomized controlled trial] evidence for the fecal occult blood test and flexible sigmoidoscopy, but not for colonoscopy screening.”
“When we make a recommendations, we look at the GRADE guidelines, that look at the quality of evidence, the balance of benefits and harms,” she said, adding that the harms of colonoscopy occur infrequently, probably “less than one percent.”
Other issues contributing to the disparity include acceptability and resources. The invasiveness of a colonoscopy is legendary: it requires prior cleansing and sedation and is uncomfortable for some, inconveniences that may put people off getting that kind of screening. There is a wait list for colonoscopies in Canada and in contrast “the FIT test and flexible sigmoidoscopy are readily available and people between 50 and 74 can go and ask their doctors for them,” said Bacchus.
Money is also serious issue when you think that the proven methods, the FIT test (which is done at home) and the flexible sigmoidoscopy (which can be done by a GP with light sedation), are much cheaper than colonoscopies delivered by gastroenterologists and others with special training. It’s a whole industry unto itself, and in Canada our system just naturally helps to rein in the profit motive.
How resources are allocated might be more of a factor in the Canadian recommendation, Dr. Bacchus said. “We think is it a wise use of resources–we do have to look at that,” noting that the wait list for colonoscopies in Canada is already long and recommending it as a screening tool would add even more burden to the wait lists.
Dr. James Allison, Clinical Professor of Medicine Emeritus at UCSF and Emeritus Investigator at Kaiser Permanente Division of Research Northern California, has widely published in this area and believes the message about colonoscopies from the Canadian Colorectal Cancer Screening Taskforce is important but must be nuanced.
He says colonoscopy is an excellent screening test, but there is no evidence that it is better at decreasing mortality from or incidence of colorectal cancer compared with a less invasive and less expensive FIT test yearly or every other year and following up with a colonoscopy if the FIT test is positive. If this is done, fewer colonoscopies will be needed and gastroenterologists will have more time to diagnose and care for their very ill patients with chronic gastrointestinal diseases, Allison said. It is a way of managing limited healthcare resources without compromising patient care. If an individual wants a colonoscopy despite the lack of evidence that it is the “best” test, they should be able to have it but, with a copay, he added.
(Anyone in Canada with a positive FIT test –which shows evidence of blood in the stool–would jump right ahead to getting a publicly-subsidized colonoscopy.)
The Canadian approach is supported by other experts in the US such as Dr. Richard Hoffman, one of our medical editors whose opinion has not wavered from an article he wrote five years ago saying that “from a public-health perspective, emphasizing colonoscopy is problematic.” His article succinctly outlined the problems: “the efficacy of colonoscopy has not been supported with randomized trial data, accuracy is imperfect, procedural quality is variable, complications are not uncommon, endoscopic capacity is limited, procedure costs are high, and many patients prefer alternative tests.”
I talked to Dr. Hoffman and he came right to the point: “We don’t need to be screening more, we need to be screening smarter,” adding that we need to reserve colonoscopy for screening high-risk patients, such as those with a family or personal history of the disease, and patients with adenomatous polyps—who are at increased risk for colorectal cancer.
In the US the National Colorectal Cancer Roundtable aims to get 80% of the population screened by 2018. Hoffman blogged about the problems with this objective, reminding us that “attempting to screen primarily with colonoscopy will be expensive, risky (complications include perforation and bleeding), and likely not the preferred option of many patients.”
At the end of the day, the public needs good clean information as urgently as we need good clean water. Hopefully the Canadian recommendations will flow more freely across the border, and stimulate even more debate in the US–especially from the US news media. Sadly much of what Americans hear about colorectal screening has been tainted by misinformation about the value of the whole spectrum of screening options.
International comparisons on medical recommendations are important, and if Americans knew that they were an outlier in the world of colon cancer screening, perhaps that fact alone might stimulate even more healthy debate in the US about the value of screening colonoscopies.
But then again, being an outlier on health care issues hasn’t influenced Americans before. Not on proton beam therapy, the proliferation of robotic surgery, national spending on health care, or universal health care — to name a few.