Once you reach middle age, your doctor will no doubt tell you to get a colonoscopy. While the procedure itself is quick and done under sedation, the dreaded “prep” of cleansing the colon scares off many people from ever having the test. With colorectal cancer ranking as the second leading cause of cancer death in the United States, doctors warn having this test after age 45 is a must.
However, a new study from Scandinavia and published in The New England Journal of Medicine is casting some doubt on that. The study compared no cancer screening to those having a colonoscopy for the first time and found only an 18% lower cancer risk in those who underwent the test. Study researchers at the University of Oslo in Norway called the results disappointing. Other experts warn this study had limitations including the fact that only 42% of the people invited to take the test didn’t get it. When results were restricted to those who actually underwent the test, the results show colonoscopies lowered the risk of colorectal cancer by 31% and reduced the risk of dying from it by half.
“On the surface the study is actually quite well-designed but not to answer the question about whether colonoscopies themselves actually decrease the risk of colon cancer or colon cancer death. They do, and the study actually proved this again,” says Dr. James McCormick, System Chief of Colon and Rectal Surgery at Allegheny Health Network (AHN) and Chairperson of the Colon and Rectal Cancer Program at AHN’s Cancer Institute. “The question they were asking with this trial design was, ‘Does recommending colonoscopy to a study population serve to decrease the risk of colon cancer or colon cancer death in the population?’ and the answer was – a little.”
McCormick points out that’s because only 42% of those people asked got the colonoscopy and that a screening test can only work if it is done. “In the population in this study, those 42% who complied with testing actually had significant reduction in colon cancer incidence and death.”
The study results may seem confusing at a time when U.S. numbers of colorectal cancer cases are growing in a younger segment of the population. Because of that, the recommended age for a first colonoscopy in this country has dropped from 50 to 45. “Unfortunately, very confusing,” McCormick adds. “The study actually concluded that colonoscopy, when performed, prevented colon cancer and colon cancer death significantly. As scientific papers go, this was a well-written and honest interpretation of a well-designed and implemented study. But when this study began to be talked about outside the scientific community, the nuance regarding the ‘pragmatic’ nature of this particular trial seems to have been lost in translation.” He says the problem is that people didn’t realize the study was not actually looking at the effectiveness of colonoscopy itself, but rather the effectiveness of screening programs that rely on patients getting a colonoscopy. McCormick says this trial actually points out the bigger problem that people often don’t comply with recommendations from their doctor.
McCormick wholeheartedly endorses lowering the age for recommended first colonoscopy to 45. “We have seen a dramatic decrease in the age of onset of colorectal cancer in the past decade and getting started earlier with screening may mitigate that risk,” he explains. “Unfortunately, that may not be enough because we have been seeing cancers in people much younger than 45.” He points to data showing the under-45 age group comprises at least 6t% of all colorectal cancer diagnoses with the risk in that age group nearly doubling in the last two decades. His message? “Yes, get screened at age 45 but if you have any symptoms at all – bleeding, pain, bloating, change in habits – get a colonoscopy no matter your age!”
Still, the reality is that many people just won’t get this test. Alternatives such as stool tests that check for blood or cancer cells (like the Cologuard brand being advertised) and X-ray and CT scan-based tests have been shown to reduce both cancer incidence and colorectal cancer deaths. However, only colonoscopy can detect and removed polyps, which are benign growths that can sometimes turn into cancers.
“I think this is the most interesting discussion that this study brings out into the light,” says McCormick. “In the United States we have achieved about 80% compliance with screening colonoscopy, unlike in this study from Europe. This was a heavy lift for us over decades – massive campaigns, celebrities getting scoped on national TV, incentives from government and insurers, etc. We should be proud of that. But this study raises the question, if, without all that fanfare, only 42% will get colonoscopy when offered, are there alternative tests that may improve compliance?”
He says this is where stool studies come in and says he’s a fan of any test someone will actually get done. This study shows poor compliance will eat into the effectiveness of any test, so alternatives may help those who don’t want a colonoscopy to somehow get screened. “If one of these tests comes back positive – you must go on to have that colonoscopy,” warns McCormick. “These tests may miss smaller lesions and, unlike colonoscopy, are unable to remove small precancerous polyps. So stool tests need to be done more frequently. They are not appropriate for anyone with any symptoms – those people need a colonoscopy.”
His takeaway? Don’t let this study change your plans to get colon cancer screening.
“Colon cancer screening works,” he says. “Colonoscopy is one way to get screened and may be the most efficient (one time every 10 years) and effective (removal of precancerous polyps prevents cancer), but it may not be for everyone. Stool tests and X-ray studies are reasonable alternatives for those who can’t or won’t get a colonoscopy. Never ignore symptoms at any age – get a colonoscopy.”