If a colonoscopy was performed every 10 years from the age of 50, 40% of cases of colorectal cancers could be avoided. These are the conclusions of a large-scale study published in the specialized journal New England Journal of Medicine September 19. Knowing that colorectal cancers cause 1.2 million deaths per year worldwide, screening may be the most effective way to fight the disease.
The authors analyzed data from 88,902 participants in two long-term studies, based on responses to a questionnaire submitted every two years between 1988 and 2008. The researchers also obtained information on colonoscopies and rectosigmoidoscopies (review limited to the lower part of the colon) performed. They analyzed 1,815 cases of colorectal cancer and 474 resulting deaths.
They found that colonoscopy, like rectosigmoidoscopy, reduced the risk of developing and dying from this cancer. Dr. Shuji Ogino, epidemiologist at Harvard School of Public Health and lead co-author of the research, explains in the scientific journal that “colonoscopy is the most common screening test in the United States, but there was no sufficient evidence so far to determine to what extent it reduces the risk of proximal colon cancer, and the necessary frequency at which this procedure should be done ”.
The proof is now made with this study. According to the researchers, only the colonoscopy reduced the risk of cancer in the proximal part of the colon, that is to say the upper part, but without allowing the same degree of protection as for cancers of the distal colon (closer to the colon).
Since 2008, free screening has been set up in France for all people aged 50 to 74. They are invited, every two years, to perform a guaiac test for occult blood in the stool. This is a test that can be performed at home: the patient must deposit a little fecal matter on the test before sending it back to the laboratory for analysis. If the test is positive, a colonoscopy should be performed. In men, colon examinations carried out following a positive test made it possible to diagnose cancer in 8.9% of cases. In women, 5.8% of colonic examinations made it possible to diagnose cancer.