NEJM colonoscopy study findings questioned by US physicians : Schott

A new European study grabbed headlines this week as it appeared to cast doubt on the efficacy of colonoscopies as a cancer screening tool. But US doctors say the study had major limitations.They cite more than a decade of research showing that colonoscopies save lives.

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A new European study grabbed headlines this week as it appeared to cast doubt on the efficacy of colonoscopies as a cancer screening tool. But US doctors say the study had major limitations.They cite more than a decade of research showing that colonoscopies save lives.

Lucha Noir/Getty Images

big european discovery study Published in New England Journal of Medicine This week seemed to raise questions about how beneficial colonoscopies are in preventing colorectal cancer. Causes of death from cancer In the United States, this result has generated much controversy and has been the subject of popular press.Screening procedures fail to prevent death from colon cancer in large study.”

But that’s not all.

Colonoscopy is a widely recommended cancer screening tool in which an endoscope is inserted into the large intestine to look for and remove potentially cancerous growths called polyps.Sometimes these slow-growing polyps, or Adenoma — would have come backTherefore, by regularly examining and removing polyps, this procedure serves both as a cancer screening tool and as an intervention to prevent tumors from developing in the first place.

Studies over a decade ago have shown that colonoscopies are possible. save lives; For example, in a 2018 study by Kaiser Permanente, 67% reduction in cancer deaths Among those who underwent screening colonoscopies.

In contrast, topline findings from this week’s NEJM study showed a mere 18% reduction in colorectal cancer among thousands of European men and women “invited” to undergo colonoscopies. indicates that Also, as some media reports have pointed out, the reduction in deaths was too small to be considered statistically significant. It’s pretty disappointing.

study hitch

But here’s the big picture: It was found that more than half of study participants who were “invited” to undergo a colonoscopy never showed up for the procedure.

“A colonoscopy only works if the patient has it,” he said. Brett Petersen, a gastroenterologist at the Mayo Clinic and president of the American Gastroenterological Endoscopy Society, the leading group of GI physicians. Peterson said it was important to look at the results of people who actually had the surgery, which was about 42% of the participants who lived in European countries, including Norway and Poland.

In this group (those who actually had a colonoscopy), the risk of getting colon cancer decreased by about 31%. “And importantly, the mortality rate has decreased by a significant percentage, about 50%,” Peterson says. He counters suggestions that a study released this week casts doubt on the efficacy of colonoscopy. “Based on the research available today, colonoscopy remains the gold standard for colorectal cancer detection and prevention,” he says. Peterson’s group, his ASGE, said colonoscopies “still The best and most proven method For patients undergoing screening for colorectal cancer. “

American Cancer Society: “These Results Show the Value of Continuous Screening”

The American Cancer Society was also involved in the study, and also noted the large number of participants who did not undergo surgery. “It’s hard to know the value of testing.” Dr. William Dahat, ACS Chief Scientific Officer. He highlights a 31% reduction in his risk of being screened.

“This result shows the value of continuous screening,” says Dahut. ACS also said it was important for study participants to consider that he had a screening between 2009 and 2014, so he had a colonoscopy eight years earlier. Some people have received it. The time from polyps to cancer to death is often very longr than this — and therefore much longer follow-up is needed,” the ACS statement concludes.Over time, the reduction in cancer or death could be greater.

The controversy generated by this study is unlikely to lead to changes in U.S. screening recommendations. Karen Knudsen, CEO of ACS recommended Colorectal cancer screening for adults over 45 years old“There’s no reason to change direction,” says Knudsen.

Some doctors are quick to point out that the methods used by endoscopists (doctors who perform surgery) have improved compared to 2009, when the European study began.

“Polyp detection rates are much higher than they were 10 to 15 years ago,” he said. Douglas Corey, research scientist and gastroenterologist at Kaiser Permanente. He notes that the equipment has improved and so has the method of preparation (patients need to fast and drink a specially prescribed laxative drink to help clear the gastrointestinal tract before the procedure). In addition, “doctors are very good at detecting and removing polyps,” says Corey. Therefore, if research were to begin now, “the benefits expected to be found now would be higher.”

Differences between America and Europe

In addition, colonoscopies are largely uncommon in the European countries where the studies were conducted, and Bret Petersen noted that some of the physicians who performed the tests had polyposis, which is considered an acceptable proportion in the United States. He said he did not specify the number. “Percentage of endoscopists who participated in the NordICC trial did not meet the adenoma detection rate,” he said. He questions whether this is in fact “just missing some of the lesions that might otherwise have been detected and removed by it”.

The study’s lead author says he is aware of all criticisms of his paper. However, he refutes the notion that endoscopists failed to find the expected level of polyps. We have a 30% detection rate, which is a quality indicator, well above the current threshold for good quality,” he says. . Michael Bretauer University of Oslo, Norway. Sweden has a much lower detection rate and fewer participants in the study because there are not as many people with polyps in Sweden. “So I don’t think that argument is valid.”

Brettthauer said the paper is getting so much attention that it may be because it challenges commonly held assumptions in the United States about how protective colonoscopies are. says no. “I think our findings suggest that colonoscopy is not a silver bullet for colorectal cancer,” he said. But he says it’s still more beneficial than most other cancer screening tools, with up to a 50% reduction in mortality risk.

Another challenge of the new study from Europe is that it was not designed to answer the questions many people have when trying to do so. Evaluate screening options“There are many ways to screen for colon cancer,” explains Kaiser Permanente’s Corley. European investigators only evaluated colonoscopies, so their study was a direct comparison to the more frequent stool-based home examinations that replace 10-yearly colonoscopies. does not provide

Alternative screening tests for colon cancer

U.S. Preventive Services Task Force Recommend one of several different types of colorectal screeningMethods such as colonoscopy, sigmoidoscopy (a less invasive test to evaluate part of the colon), or stool-based tests that are usually taken at home and mailed to a laboratory, Look for blood or abnormal cells in a stool sample.

“It is not clear whether any of these methods are better than the other in reducing deaths from colon cancer,” Corey says.

A stool immunochemical test called FIT can detect small amounts of blood in the stool. usually held annuallyAnother option is a combination test like this: Koroguard –– Detect both blood and DNA changes that may originate from cancerous or precancerous polyps in stool. Those who choose this option are generally advised to test every three years.

Kaiser Permanente patients more commonly opt for the FIT test. Sometimes the biggest hurdle is remembering to take the test. Cory says he mails the stool-based test to the patient at Kaiser and continues to contact the patient until the test is returned.

Each screening approach “has its strengths and weaknesses,” Corey says. If the stool sample test is positive, a colonoscopy is likely recommended to improve appearance and remove polyps. Colonoscopies include risks of perforation or tearing of the colon, bleeding at the biopsy site (if the doctor removes the polyp or performs a biopsy), and potential side effects of sedation during the procedure. It comes with a small risk.

Usually, “if you’re at high risk for colon cancer, such as having a close relative who had colon cancer, it’s a good idea to get a colonoscopy, especially if you’re young,” Corey says. Say. If the risk is not high, you should choose a test that you can complete, whether it be a colonoscopy or a less invasive and more frequent stool-based test.

Regardless of which method of colon cancer screening you choose, Corley says the key is to do it and get screened.

You can find Allison Aubrey on Twitter @AubreyNPR.