- A study in the New England Journal of Medicine shows that colonoscopies are not as helpful as many had hoped.
- But health experts say the new study does not change the way doctors think about colonoscopies.
- The Preventive Services Task Force encourages all adults aged 45 to 75 to be screened for colorectal cancer.
For more than 20 years, American adults have been advised to get colonoscopies starting in middle age to prevent colon cancer.
But the evidence supporting colonoscopy has never met the “gold standard” of research trials, so it has been unclear how effective screening is in preventing cancer and saving lives.
A new study conducted in European countries where colonoscopies were not routinely offered suggests that this procedure may not be as effective as many had hoped. But others Health experts warn against misinterpreting the results of this study.
“There’s a lot of diversity here, so it’s understandable that there are different takes from different people,” said Dr. Chris Manz, a gastroenterology oncologist at the Dana-Farber Cancer Institute in Boston.
According to the New England Journal of Medicine study
Take away: The report suggests screening colonoscopies made a small difference in colon cancer detection rates and mortality, but that’s not the whole story.
In this study, more than 84,000 people aged 55 to 64 from Norway, Poland and Sweden were either “invited” to receive a colonoscopy or given “usual care,” which in those countries does not include screening for colon cancer at all. They were then followed for 10 years to see who developed colon cancer.
Only 42% of the 28,220 participants in the “invited” group had the procedure, compared to about 56,300 participants who received “usual care” and did not receive a colonoscopy.
When the researchers checked 10 years later, 255 people in the invited group had developed colon cancer and 622 in the conservative group doubled. The death rate between the two groups was almost the same.
But if all the participants who were put on the screen had actually done it, the risk of dying from colon cancer would have been cut by 50%.
What health experts think
Take away: A new study doesn’t change how doctors think about colonoscopies.
The study says more about the quality of the screening than it does about the process, experts say, as half of the “invited” group did not receive an invitation to take it.
“I don’t think this should change our approach,” said Dr. Robin Mendelsohn, a gastroenterologist at Memorial Sloan Kettering Cancer Center in New York City. “The important thing is still to be tested, still to have a discussion” with your doctor.
Colonoscopies are also recommended in the U.S. — where uptake is more than 70 percent — compared to “study invitations,” Manz said.
Is colonoscopy the only way to diagnose colon cancer?
Take away: Colonoscopies are the most common, but there are other options.
Although no one needs colonoscopies, due to the preparation and discomfort, they are considered the best diagnostic tool because they can detect and remove precancerous polyps.
In recent years, stool tests have gained popularity because they can be done at home and do not require preparation.
“Tests are good for detecting cancer,” Mendelsohn said, but they don’t rule out cancer growth and a good test needs to follow a colonoscopy.
What happens at a colonoscopy? Is it a painful process?
Take away: Colonoscopy is a test to detect changes in the colon and rectum, and is one of the few options for screening for colorectal cancer, according to the Mayo Clinic.
During the procedure, a long, flexible tube with a small video camera on the tip is inserted into the rectum, allowing doctors to see inside the colon.
Colonoscopies take about 15 to 20 minutes and recovery is minimal with most patients sedation wears off within an hour, Manz said.
The procedure is painless, he said, but some patients may experience bloating or gassiness.
When should you get a colonoscopy? And how often?
Take away: The Preventive Services Task Force encourages all adults aged 45 to 75 to be screened for colorectal cancer.
Some people may want to start testing earlier if they have inflammatory bowel disease, a family history of other conditions, or other factors that increase their risk of colorectal cancer, according to the Centers for Disease Control and Prevention.
Adults who are not at increased risk should get a colonoscopy every 10 years after their first screening, health experts say.
What are the risks that can cause breast cancer?
Take away: The guidelines say the biggest risks include a family history of colon cancer, a genetic predisposition for cancer and a history of inflammatory bowel disease, radiation to the abdomen, or a history of precancerous polyps, Mendelsohn said.
Other risk factors include obesity, smoking, alcohol consumption, lack of exercise and a diet high in processed meats and low in vegetables.
Anyone with persistent bleeding, abdominal pain, or bowel changes should be evaluated “immediately,” Mendelsohn said.
Experts say that stomach cancer is increasing in people under the age of 40 for reasons that are not fully understood. But still, the risk of colon cancer is small and falling, said Dr. Gil Welch, a senior investigator at the Center for Surgery and Public Health at Brigham and Women’s Hospital in Boston.
In this study, 1.2% of people who did not receive a diagnosis were diagnosed with colon cancer. Getting a colonoscopy reduced that risk to .8% – a 50% drop but still a small risk overall.
“We’re starting to get a real picture of the size of the results of colonoscopies and it’s more moderate than advertised,” Welch said.
Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.
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