Many people in the U.S. may now be thinking that they’ve received a blessed reprieve from a middle age rite of passage: the colonoscopy.
After all, a large study just made headlines for suggesting the procedure isn’t nearly as effective at lowering the risk of colon cancer as previously thought. Worse, it didn’t seem to have any impact on lowering the risk of dying from the disease.
But no one should cancel their colon cancer screen.
The trial was important and well run, but it would be a mistake to take it as an indictment of the colonoscopy.
Rather, the study should reinforce the need to closely compare the real-world risks and benefits of preventative testing – and serve as a reminder that those benefits might look less impressive as the overall population gets healthier.
The study, published in the New England Journal of Medicine, involved nearly 85,000 people in Norway, Poland and Sweden, who were randomly assigned to be invited to get a colonoscopy or to not be offered one.
The volunteers were then followed for a decade to see if a colonoscopy lowered their risk of getting cancer and dying from it.
The risk of colon cancer was about 18% lower in the group that was invited to get a colonoscopy, and deaths from colon cancer were roughly equal among the two groups.
Previous studies, which weren’t done in this randomized, controlled fashion, had suggested colonoscopies reduced the risk of colon cancer by anywhere from 40% to 69%, and lowered the risk of death by anywhere from 29% to 88%.
There’s no sugarcoating it: The colonoscopy’s modest effect was a surprise and disappointment. But the takeaway shouldn’t be that colonoscopies don’t work or aren’t worthwhile.
Instead, the takeaway from the trial is that very few people are going to RSVP enthusiastically to an invitation to get a colonoscopy.
The study was designed to gauge how well a population-level screening program worked in the real world – not to understand the difference between getting or not getting a colonoscopy.
In the end, the main thing that the study clearly shows is that widespread efforts to screen the population with colonoscopy “may have limited benefit,” said Benjamin Rome, a general internist and health policy researcher at Harvard Medical School.
But that benefit is still important when it comes to lowering the risk of colon cancer, and the study also suggests it might grow over time.
One last thing that’s worth considering: Sometimes good news can be buried in the bad news. Rates of colon cancer and deaths in the study were lower overall than the researchers had expected when designing the trial.
To be crystal clear: The results do not mean there’s no value in screening for colon cancer. The question, rather, is whether a colonoscopy is the best way to do it, or if a non-invasive and cheaper test like the also-recommended stool-based testing is as good or better for most people.
About the Author
