Polish researchers, together with scientists from Norway, Sweden and the Netherlands, assessed the impact of screening colonoscopy on the reduction of incidence and death from colorectal cancer. The New England Journal of Medicine published the results of the NORDICC study conducted in 4 countries, in which researchers from the National Institute of Oncology Maria Skłodowskiej Curie and the Medical Center of Postgraduate Education in Warsaw under the supervision of prof. Michał Kamiński.
Effect of colonoscopy on the reduction of incidence and death from colorectal cancer. New research results
Published Oct. 14, 2022 11:25
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It is the world's first randomized trial to assess the impact of screening colonoscopy on the risk of developing and dying from colorectal cancer. The scientific evidence to date assessing the magnitude of the reduction in the risk of developing and dying from colorectal cancer after colonoscopy has been obtained in observational studies.
The NORDICC (Northern European Initiative on Colorectal Cancer) study was conducted in 4 countries: Norway, Sweden, the Netherlands and Poland. Almost 85,000 people were included in the analysis.
After 10 years of follow-up of the entire invited population ( intention to treat analysis), there was a significant 18% reduction in colorectal cancer risk, and a 10% reduction in colorectal cancer death ( statistically insignificant).
The percentage of people who underwent screening colonoscopy after receiving a written invitation was 42%. In the analysis of only people who underwent a colonoscopy after a written invitation (analysis per protocol) , the reduction in the risk of colorectal cancer was 31%, and the reduction in death from it - 50% (both values are statistically significant) .
The publication suggests that in order to increase the effectiveness of screening colonoscopy, the reporting of invited patients should be significantly increased. A solution could also be to introduce less invasive methods to screening tests, such as a fecal occult blood test, and to perform a colonoscopy only after an abnormal result of this test.
In light of the evidence so far, the most important conclusions of the NORDICC study are as follows:
1. The reduction in the incidence (31%) and the risk of death (50%) due to colorectal cancer after screening colonoscopy is less than estimated so far based on observational studies.
2. Too low reporting for screening colonoscopy (42%) limits its impact on effectiveness on a population scale.
3. According to the study protocol, the final analysis is planned after 15 years of follow-up.
Bretthauer M, Løberg M, Wieszczy P, Kalager M, Emilsson L, Garborg K, Rupinski M, Dekker E, Spaander M, Bugajski M, Holme Ø, Zauber AG, Pilonis ND, Mroz A, Kuipers EJ, Shi J , Hernán MA, Adami HO, Regula J, Hoff G, Kaminski MF; NordICC Study Group. Effect of colonocopy screening on risks of colorectal cancer and related death. New Engl J Med 2022, Oct 9, doi: 10.1056/NEJMoa2208375
