Effect of Colonoscopy Screening on the Risks of Colorectal Cancer and Related Death
abstract
This abstract is available on the publisher's site.
Access this abstract nowBACKGROUND
Although colonoscopy is widely used as a screening test to detect colorectal cancer, its effect on the risks of colorectal cancer and related death is unclear.
METHODS
We performed a pragmatic, randomized trial involving presumptively healthy men and women 55 to 64 years of age drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio to either receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the usual-care group). The primary end points were the risks of colorectal cancer and related death, and the secondary end point was death from any cause.
RESULTS
Follow-up data were available for 84,585 participants in Poland, Norway, and Sweden - 28,220 in the invited group, 11,843 of whom (42.0%) underwent screening, and 56,365 in the usual-care group. A total of 15 participants had major bleeding after polyp removal. No perforations or screening-related deaths occurred within 30 days after colonoscopy. During a median follow-up of 10 years, 259 cases of colorectal cancer were diagnosed in the invited group as compared with 622 cases in the usual-care group. In intention-to-screen analyses, the risk of colorectal cancer at 10 years was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio, 0.82; 95% confidence interval [CI], 0.70 to 0.93). The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16). The number needed to invite to undergo screening to prevent one case of colorectal cancer was 455 (95% CI, 270 to 1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (risk ratio, 0.99; 95% CI, 0.96 to 1.04).
CONCLUSIONS
In this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening. (Funded by the Research Council of Norway and others; NordICC ClinicalTrials.gov number, NCT00883792.).
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Additional Info
Disclosure statements are available on the authors' profiles:
Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death
N. Engl. J. Med 2022 Oct 09;[EPub Ahead of Print], M Bretthauer, M Løberg, P Wieszczy, M Kalager, L Emilsson, K Garborg, M Rupinski, E Dekker, M Spaander, M Bugajski, Ø Holme, AG Zauber, ND Pilonis, A Mroz, EJ Kuipers, J Shi, MA Hernán, HO Adami, J Regula, G Hoff, MF KaminskiFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Be careful of medical headlines
The medical headline for this northern European study was, “Colonoscopies have a lower-than-expected benefit in preventing colon cancer (18% reduction), with no reduction in colon cancer mortality.”
This finding is based on lumping everyone in the “invited” group. However, only about half of those invited for colonoscopy chose to have it done. This dilutes the results in half. When the authors only included those subjects who underwent the test, the reduction in colon cancer increased to 30%, with an associated decrease in colon cancer death.
Another concern is the population studied. Compared with Americans, northern Europeans have a better diet that includes more fish and high-fiber foods, which is associated with a lower risk of colon cancer. If this study was done in America, the risk of colon cancer would be higher due to the consumption of processed foods and higher rates of obesity. Prior research has shown that a pesco-vegetarian diet is associated with a 46% reduction in colon cancer risk.1
Will this study change what we do?
Probably not. Colonoscopy is still the most sensitive test that should be encouraged for individuals at the highest risk of colon cancer. For everyone else, the best test is the one they will do.
Colonoscopy every 10 years
Sigmoidoscopy every 5 years
Stool DNA (Cologuard) every 3 years
Fecal Immunochemical Testing (FIT; antibody testing for blood) every 1 to 2 years
Reference
This study randomized a total of 84,585 participants from Norway, Poland, and Sweden in a 1:2 ratio to colorectal cancer (CRC) screening colonoscopy or no screening (usual care).
Major concerns
Do not lose sight of this when reading the headlines in the media around this study. High-quality performance of colonoscopy is the key to optimize outcomes; hence, there are major questions around quality performance in this study.
We would like to bring the statement by the ASGE to your attention regarding this article in NEJM on colonoscopy screening results; click here for the full statement.