Steering away from America’s emphasis on colonoscopy, the Canadian Task Force on Preventive Health Care (CTFPHC) is recommending that patients undergo fecal occult blood testing (FOBT) every 2 years or flexible sigmoidoscopy every 10 years to screen for colorectal cancer. The new guideline appears in the Canadian Medical Association Journal (CMAJ).
At least 25,000 Canadians received a colorectal cancer diagnosis in 2015, and 9,300 died of the disease. Getting a colonoscopy in Canada isn’t that easy—waiting lists have gotten progressively longer over the years, said Maria Bacchus, MD, chair of the CTFPHC guideline working group and a general internist in the Department of Medicine at the University of Calgary in Alberta, in a statement.
“Although colonoscopy may offer clinical benefits that are similar to or greater than those associated with flexible sigmoidoscopy, direct evidence of its efficacy from randomized controlled trials in comparison to the other screening tests…is presently lacking; however, ongoing clinical trials are working to address this research gap,” Bacchus noted.
CTFPHC strongly recommends that asymptomatic, low-risk adults ages 60 to 74 get screened once every 2 years using an FOBT method (either a guaiac smear method or Fecal Immunochemical or FIT Test) or once a decade using flexible sigmoidoscopy. The task force recommended the same combinations of tests, though not as urgently, for those between the ages of 50 and 59.
The new recommendations reduce the frequency of testing under these methods from the 2001 guideline, which recommended FOBT every 1 to 2 years, and flexible sigmoidoscopy every 5 years.
Citing lack of clinical evidence, the task force did not recommend colonoscopy as a primary screening test for colorectal cancer. It also didn’t support screening adults ages 75 years or older for this disease, but instead recommended that these individuals consult with their physicians about the pros and cons of screening.
CTFPHC indicated that it would continue to track scientific developments in colorectal cancer screening, with a goal of updating the 2016 guidelines in 5 years.
Colonoscopy remains an important screening tool in the United States, but as CLN Stat reported in October 2015, emphasis on other methods is growing.
In a series of draft recommendations still under review, the U.S. Preventive Services Task Force last fall proposed colonoscopy every 10 years in addition to other options, such as a yearly FIT or high-sensitivity guaiac-based FOBT, or flexible sigmoidoscopy every 10 years in combination with an annual FIT test.
USPSTF remains firm that adults 50 and over should get screened for colorectal cancer.
Some in the medical community tend to favor Canada’s approach to screening otherwise healthy, asymptomatic adults with methods that are less invasive than colonoscopy.
“I think [colonoscopy] is a great test, but in terms of population-based colon cancer screening, I don’t think that is the right test,” Jennifer Telford, MD, medical director of the BC Cancer Agency’s colon screening program, told The Globe and Mail.