No one ever looks forward to a colonoscopy, but it's long been framed as a crucial tool in the fight against colon cancer. As Stat News notes, "gastroenterologists put colonoscopies on a pedestal" for decades. Now, a new 10-year study out of Europe puts somewhat of a damper on that, in the first large randomized clinical trial that compares patients who received colonoscopies—in which a doctor searches for precancerous polyps by inserting a camera into the patient's rectum—to those who didn't. For their research published Sunday in the New England Journal of Medicine, scientists gathered nearly 85,000 adults between the ages of 55 and 64 in Poland, Sweden, Norway, and the Netherlands, then invited about 28,000 of those patients to receive a colonoscopy; the rest of the study's subjects received their usual care, without regular colonoscopy screening.
About 42% of those who received the colonoscopy invite accepted it, and the researchers then kept tabs on the entire group for a decade, tracking colonoscopies, colon cancer diagnoses, and deaths from colon cancer. What they found is that those who received a colonoscopy invite only saw about an 18% decrease in colon cancer risk—and no significant difference in colon cancer deaths from the group that hadn't received an invite. Past research had shown much higher numbers, in favor of colonoscopies. How disappointed are gastroenterologists about this? "I think we were all expecting colonoscopy to do better," says Samir Gupta of UC San Diego, per Stat. Others are warning, however, not to discount the procedure's use as a helpful screening tool, pointing to the fact that it does decrease colon cancer risk somewhat, even if it's not at the level that researchers had hoped for.
Dr. Jason Dominitz, head of gastroenterology for the Veterans Health Administration and co-author of an NEJM editorial that accompanied the new study (he didn't work on the study himself), tells CNN that US research has found colonoscopies to be more effective than this study suggests. He notes that higher success rate may be because patients in the US almost always are sedated when getting a colonoscopy, meaning doctors can be extra-thorough. Less than a quarter of the patients in this most recent study were sedated. Dominitz also points out that less than half of those who received the colonoscopy invite actually took researchers up on it, and that the results may have leaned more in favor of the procedure if they had. "The most important message is that colon cancer screening is effective," Dominitz stresses. (Read more colonoscopy stories.)