VIENNA — People who had one colonoscopy had a lower risk of colorectal cancer and associated mortality than those who had no colonoscopy. , Randomized Nordic Initiative for Colorectal Cancer (Nord ICC) trial show.
In practice, this means that the number of people who need to be invited to be screened to prevent one case of colorectal cancer is 455 (95% CI: 270 – 1429), said the researchers. has decided.
The results were presented today at the European Union Gastroenterology (UEG) Week 2022. European Union Gastroenterology (UEG) 2022 was with the meeting It was published at the same time New England Journal of Medicine.
The results of this study, which is truly population-based and designed to mimic a national colorectal cancer screening program, provide an estimate of the screening efficacy of colonoscopy in the general population.
Primary outcome was determined based on intent and screening. All persons invited to undergo colonoscopic screening were compared with those who received usual care (that is, neither invited nor screened). At UEG 2022, researchers presented a preliminary value for his 10-year colorectal cancer risk. This he found to be 0.98% against 1.20%. This represented an 18% reduction in risk for colonoscopy invitees (risk ratio 0.82; 95% CI: 0.70 – 0.93). During the study period, 259 cases of colorectal cancer were diagnosed in the invitation group, compared with 622 cases in the usual care group.
The risk of dying from colorectal cancer was 0.28% in the invitation group and 0.31% in the usual care group (risk ratio 0.90; 95% CI: 0.64 – 1.16). The risk of death from any cause was similar in both the invited and usual care groups at 11.03% and 11.04%, respectively (risk ratio 0.99; 95% CI: 0.96 – 1.04).
The authors say the benefits would have been greater if more people had been screened. Only 42% of those invited actually had a colonoscopy. In an adjusted analysis, the 10-year risk of colorectal cancer decreased from 1.22% to 0.84% if all persons invited to undergo screening underwent colonoscopy, and the 10-year risk of colorectal cancer-related The risk of death has decreased from 0.30. % to 0.15%.
The researchers, led by gastroenterologist Michael Bretauer, The MD of the Department of Gastrointestinal Endoscopy Medicine, University of Oslo, who presented the data at UEG 2022 on behalf of the NordICC study group, said, “Despite the observed substantial reduction in relative risk, the absolute risk of colorectal cancer remains low. The risk, and even the risk of death associated with colorectal cancer, was lower than in previous screening trials and lower than expected when the trial was designed.”
However, they add, “In the light of the 50% reduction observed in the adjusted protocol-by-protocol analysis, optimism regarding the effect of screening on colorectal cancer-related death may be warranted.” .
With co-authors, Brettthauer said even their adjusted findings “probably underestimated the benefits because, like most other large trials of colorectal cancer screening, all significant because we were unable to adjust for significant confounding factors.”
Brettthauer also noted that results were similar to those obtained with sigmoidoscopic screening. In close comparison, sigmoidoscopy studies showed a 33% to 40% reduction in the risk of colorectal cancer according to protocol analysis.
“These results suggest that screening by colonoscopy may not reduce the risk of colorectal cancer significantly more than sigmoidoscopy.”
Real-world population-based studies
The NordICC is an ongoing pragmatic study and the first randomized trial to quantify the benefit of colonoscopy screening on the risk of colorectal cancer and related mortality.
Researchers recruited healthy men and women from registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. Most participants came from Poland (54,258), followed by Norway (26,411) and Sweden (3,646). Dutch data could not be included due to data protection laws.
At baseline, 84,585 participants aged 55 to 64 years were randomized in a 1:2 ratio and invited to undergo one colonoscopy (28,220; ) or receive usual care per participating country (56,365; uninvited or screened).
Detected colorectal cancer lesions were removed whenever possible. The primary endpoint was the risk of colorectal cancer and colorectal cancer-related mortality. The secondary endpoint was death from any cause.
“Moderate effect” but longer follow-up to get the big picture
Editorials accompanying the publication of this study are by Jason A. Dominitz, MD, Department of Gastroenterology, University of Washington School of Medicine, and Douglas J. Robertson, MD, White River Junction Veterans Affairs Medical Center. , White, Vermont. His River Junction comments on possible reasons for the lower reduction in cancer incidence and deaths seen in the NordICC.
They point out that cohort studies suggest a 40% to 69% reduction in colorectal cancer incidence and a 29% to 88% reduction in the risk of dying from colonoscopy. However, “cohort studies likely overestimate the actual effectiveness of colonoscopies because of poor adherence to the test and the tendency of healthier people to seek preventive care.” This is because it is not possible to adjust for important factors such as
Citing Brettthauer’s remarks on participation in screening, Dominitz and Robertson noted that colonoscopy is the primary form of screening for colorectal cancer in the United States, and that colonoscopy is less established in countries where colonoscopy is less established. adds that participation can vary significantly.
“The actual efficacy of colonoscopy in a population more receptive to colonoscopy may be closer to the efficacy shown in the protocol-by-protocol analysis of this trial,” they wrote. increase.
The editors also point out that the benefits of colonoscopy screening will take time to be realized. A reanalysis and final analysis of the NordICC data is planned at 15 years of follow-up.
Furthermore, they noted that “colonoscopy is highly operator-dependent” and that adenoma detection rates are variable, affecting cancer risk and associated mortality.
Given the “moderate efficacy” of colonoscopy screening in the trial, they argue: Simpler, less invasive strategies (such as sigmoidoscopy and FIT) are available. “
However, they also said, “Additional analyzes including results from longer follow-up and other ongoing comparative efficacy trials will help us to fully understand the benefits of this trial.” .
Also commenting on the study was Michiel Maas, MD, Department of Gastroenterology and Hepatology, Radboudam, Nijmegen, The Netherlands. Medscape Medical News He agreed that the absolute impact on colorectal cancer risk or colorectal cancer-related mortality was not as high as expected and may be disappointing.
But Maas said, “About half of the patients in this study did not have a colonoscopy, which could have adversely affected the results.
“An additional factor that may influence colonoscopy studies is potential variability in detection rates between operators/endoscopists,” he said.
Looking to the future, Maas said: [artificial intelligence] Or computer-aided detection could level this race in detection rate.
“Nevertheless, this is a very interesting study and sheds new light on the efficacy of colonoscopy screening,” he said.
Brettauer has ties to Paion, Cybernet, and the Norwegian Council of Research. Dominitz said he co-chaired VA Cooperative Studies Program #577: “Colonoscopy vs. Fecal Immunochemistry (FIT) in Reducing Mortality from Colorectal Cancer” (CONFIRM study), which Funded by the U.S. Department of Veterans Affairs. Robertson is the National Co-Chair (along with Dominitz) of the CONFIRM trial, and he receives personal fees from Freenome outside of submitted work. Mars has not reported any relevant financial relationships.
United European Gastroenterology (UEG) Week 2022: Abstract LB08. Announced October 10, 2022.
N Engl J Med. Published online on October 9, 2022. Overview
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