A Randomised Clinical Trial Tests the Benefits of Colonoscopies
A randomised trial suggests that the advantages of colonoscopies for cancer screening may be overestimated. The study included more than 84,000 men and women aged 55 to 64 from Poland, Norway and Sweden, who never had a colorectal cancer screening test before.
Between 2009 – 2014, they were either invited to a colonoscopy screening, or they were monitored without receiving a screening test. Following 10 years after enrollment, results suggested that those who received screening only had a small reduction in their risk of death from colorectal cancer. However, there is a possibility it is just due to chance as the difference was not statistically significant. Within this randomised trial, participants who had a screening were compared with the participants who had no screening at all. The study found only an 18% lower risk of getting colorectal cancer and no significant risk of death from colorectal cancer.
However, when the authors decided to restrict the results to the people who received colonoscopies, which accounted for approximately 12,000 people out of more than 28,000, the results showed that the risk of colorectal cancer was reduced by 31%, reducing the risk of death by 50%.
Study researcher and gastroenterologist, Dr. Michael Bretthauer, expressed his thoughts concerning the results of the study. He believes the results of the full study, including people who did and did not receive colonoscopies,show the minimum benefit that colonoscopies can provide to a screened population.Whereas, the results from the subset of people who received the test shows the maximum benefit people could gain from receiving a colonoscopy screening.
Therefore, based on the results, he expects that the risk of colorectal cancer will be reduced by 18% to 31% and the risk of death will be reduced from 0% to a maximum of 50%. He added that 50% is still “on the low end of what I think everybody thought it would be".
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Bretthauer Met al (2016) Population-Based Colonoscopy Screening for Colorectal Cancer: A Randomized Clinical Trial. JAMA Intern Med.176(7):894–902