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Colon cancer testing: Collecting your poop is worth the peace of mind
Marie looked down at her toilet, a paper plate in one hand and a stool testing kit in the other, and wondered, “Do I really have to do this?” When she turned 50, her doctor had recommended checking her stool for blood using a FIT (fecal immunochemical test), which had led to her moment of doubt in the bathroom.
It’s most certainly not a glamorous exercise, but screening for colorectal cancer (CRC) is important. One in 13 men and one in 16 women in Alberta will eventually be diagnosed with CRC, and it is the second leading cause of cancer death in the United States. Risk increases with age, especially over 50. CRC screening dramatically reduces the risk of dying from colon cancer and saves lives.
Colon cancers usually begin as polyps that can be detected and removed during colonoscopy before developing into potentially fatal cancers. The average person can drop their lifetime risk of dying from colon cancer by 82 per cent through CRC screening. This makes the case for screening a compelling one, with a clearer benefit not seen with any other cancer detection strategies. Looking at it another way, CRC screening adds 250 years of life expectancy to every 1,000 individuals who decide to undergo it.
Marie felt fine, and her bowel habits were normal. She had asked her doctor if there was an easier way of screening for CRC — a blood test maybe? But her doctor responded that a FIT was the best way, all things considered, for those at average risk of the disease. You may be aware of other methods of colon cancer screening: stool testing has been used in various forms for decades. But previous methods were plagued by problems — they could be falsely positive if you ate a rare steak or if you were on iron pills. Another option is taking a direct look at the colon using a colonoscopy procedure, during which a physician uses a small camera inserted into the rectum to look for suspicious lesions. But it is a more invasive test than a FIT, and there can be rare but serious complications such as bowel perforation or bleeding.
To complete a FIT test, one starts by collecting their stool, either on a paper plate or on some provided paper that is artfully arranged over the toilet bowl. A small bit of stool is dabbed onto the test wand, and then inserted into a collection bottle and stored in the fridge until it is ready to be dropped off at the lab. When an early cancer or pre-cancerous polyp is lurking in the colon, it usually sheds minuscule amounts of blood that the FIT test can detect. Those with positive FITs then need a colonoscopy. Once you’ve had a normal colonoscopy, you don’t need any additional testing (FIT or otherwise) for 10 years.
How does FIT for everyone 50 to 75 years old compare to using colonoscopy? A June report in the journal JAMA by the United States Preventive Services Task Force (USPSTF) colorectal screening panel weighed in on this question.
The panel made a strong recommendation in favour of screening all healthy individuals between 50 and 75 years of age, as the benefits of this sort of comprehensive screening strongly outweigh the risks. The USPSTF did not endorse one particular screening approach over another, but suggested that FIT testing or colonic imaging, either as colonoscopy or CT scan, were likely the most promising strategies. Given the need to repeat FIT testing every year or two and the 10-year “clean bill” that comes with colonoscopy, the task force recommended that patient preference be used to determine how to optimally proceed. Some people might prefer to just do a FIT every couple of years and forgo the more invasive colonoscopy, while others might feel comforted by the notion of having every inch of their colon inspected by a physician.
Notably, the Alberta Medical Association and Alberta Health Services both support FIT testing as the way to go, presumably because of its minimal risks and cost-effectiveness. In addition, wait lists for routine colonoscopy are already long, so using it as a screening tool for everyone between 50 and 75 years old would be a daunting logistical challenge. The Canadian Task Force on Preventive Health Care also makes a strong recommendation in favour of stool testing and discourages colonoscopy as the screening test of choice.
Some important caveats: these recommendations pertain to individuals at average risk of CRC and without any high-risk factors. Certain people are more prone to CRC, including those with first-degree relatives who have had it, those with diabetes, and those with the bowel disease ulcerative colitis. Lifestyle also has a role — sedentary lifestyle, heavy alcohol intake, obesity and smoking are all associated with greater risk. And all of this only applies to people with no symptoms of CRC: those with symptoms like rectal bleeding, abdominal pain or bloating, and unexplained weight loss require urgent colonoscopy. In those older than 75, the decision to screen for CRC should be individualized by considering general health status, ability to tolerate cancer treatment if a tumour is found, and of course patient preference.
So back to Marie in the bathroom with her paper plate: the off-putting task of collecting your stool sample is a small price to pay for an innovation in cancer screening technology that can save your life. If you’ve celebrated the big 5-0 make sure to get FIT testing through your family physician.
This column does not represent a substitute for advice from your personal physician.