Colonoscopy screening is less effective at preventing patients from dying of colorectal cancer

Colonoscopy screening is less effective at preventing patients from dying of colorectal cancer

On October 10th, the world's first randomized study on the use of colonoscopy screening to prevent colorectal cancer was presented as part of the UEG Week 2022 in Vienna. The United European Week of Gastroenterology is the leading congress for intestinal and intestinal diseases, bringing together more than 14,000 participants each year.

The full study was published in the New England Journal of Medicine (NEJM).

– Unfortunately, colonoscopy is not a miracle cure for colon cancer. According to our study, it is probably no better than the stool samples, says Michael Bretthauer, professor at the University of Oslo and senior physician at Oslo University Hospital.

Until now, experts assumed that the effect of colonoscopy in detecting colon cancer was higher than using stool samples. Stool samples are now used in screening programs worldwide. Researchers believe that up to nine out of ten cases of colon cancer can be prevented with a colonoscopy. When it comes to stool samples, it is assumed that this is the case in two to three cases out of ten. In the NordICC study, researchers wanted to find out whether colonoscopy can actually help prevent colon cancer.

In the study, 1.2 percent of people who were not randomly assigned to colonoscopy screening developed colon cancer after 10 years, compared to 0.98 percent in the group that was offered screening.

“This means that the number of new cases of colon cancer fell by 18 percent among participants who were offered a colonoscopy,” says Bretthauer.

The study is led by Bretthauer and colleagues in the Clinical Effectiveness Research group at the University of Oslo and Oslo University Hospital. The study is called NordICC, Nordic-European Initiative on Colorectal Cancer.

The researchers tracked 95,000 participants from four European countries over a period of more than ten years

95,000 participants from Norway, Sweden, Poland and the Netherlands are taking part in the study. It is one of the largest randomized trials ever conducted.

Healthy people between the ages of 55 and 64 were randomized into two groups: one group was offered screening with colonoscopy, the other was not offered screening at all. All participants in the study were followed for over ten years to determine whether colonoscopy prevented colon cancer.

In Norway, screening centers were set up at Sørlandet Hospital in Kristiansand and Arendal, which performed thousands of colonoscopies for the study between 2009 and 2014.

Authorities should take the results of the study into account when designing the new Norwegian screening program

The mortality rate for colorectal cancer is generally low in the NordICC study. Only three in a thousand died from the disease in the ten years the researchers followed the participants, regardless of whether they were offered screening or not. There was no significant decrease in mortality rates in the screening group compared to the group that was not offered screening.

– We are pleased that the overall mortality rate in the study is low. The numbers are lower than expected at the beginning of the study, says Bretthauer.

The main reason for the low mortality rates is that treatment options for colorectal cancer have noticeably improved over the last decade. This makes colonoscopy less effective at preventing patients from dying of colon cancer.

– This may mean that the introduction of colonoscopy as part of the colorectal cancer screening program in Norway may be less effective than previously thought. Researchers and authorities should now discuss how the program should proceed, taking into account the results of the NordICC study, says Bretthauer.

Researchers will follow study participants over the coming years to see whether the effect of screening improves over time. The study's next report is expected to be published in two years.

Source:

University of Oslo, Faculty of Medicine

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