Abstract
BACKGROUND & AIMSScreening endoscopy reduces colorectal cancer (CRC) incidence but the time course and magnitude of effects beyond 10 years after screening are unknown. We aimed to estimate the expected time course and magnitude of long-term impact of screening endoscopy on CRC incidence.METHODSWe used Markov models based on the natural history of the disease along with data from the German national screening colonoscopy registry to derive the expected impact of screening colonoscopy at age 55 or 60 on cumulative CRC incidence according to time of follow-up over a period of up to 25 years.RESULTSAfter a single screening colonoscopy, cumulative CRC incidence is expected to be increased for approximately 4 to 5 years. This transient increase is expected to be followed by a steadily increasing reduction in cumulative CRC incidence for at least 25 years. Less than one third of this long-term reduction is expected to be seen within 10-12 years of follow-up, the length of follow-up reported on in RCTs on flexible sigmoidoscopy screening and in most cohort studies on both sigmoidoscopy and colonoscopy screening. In relative terms, risk reduction is expected to reach its maximum approximately 15 years after a single screening colonoscopy and 20-25 years after the initial screening colonoscopy in case of repeat screening colonoscopy after 10 years.CONCLUSIONSThe long-term impact of screening endoscopy on CRC prevention is expected to be much stronger than suggested by currently available evidence from RCTs and cohort studies with limited length of follow-up.
Highlights
Several randomized clinical trials (RCTs) have demonstrated effective reduction of colorectal cancer (CRC) incidence by screening with flexible sigmoidoscopy (FS). [1,2,3,4,5] Observational studies likewise suggest strong reduction of CRC incidence by screening FS and screening colonoscopy. [5] Results from randomized controlled trial (RCT) on the impact of screening colonoscopy on CRC incidence are not available yet
We used Markov models based on the natural history of the disease along with data from the German national screening colonoscopy registry to derive the expected impact of screening colonoscopy at age 55 or 60 on cumulative CRC incidence according to time of follow-up over a period of up to 25 years
Less than one third of this long-term reduction is expected to be seen within 10-12 years of follow-up, the length of follow-up reported on in RCTs on flexible sigmoidoscopy screening and in most cohort studies on both sigmoidoscopy and colonoscopy screening
Summary
Several randomized clinical trials (RCTs) have demonstrated effective reduction of colorectal cancer (CRC) incidence by screening with flexible sigmoidoscopy (FS). [1,2,3,4,5] Observational studies likewise suggest strong reduction of CRC incidence by screening FS and screening colonoscopy. [5] Results from RCTs on the impact of screening colonoscopy on CRC incidence are not available yet. [5] Results from RCTs on the impact of screening colonoscopy on CRC incidence are not available yet. A crucial issue in reporting and interpreting the results of studies on the impact of screening FS or colonoscopy on CRC incidence is the length of followup: Detection of prevalent CRC cases at screening leads to an apparent initial increase in CRC incidence, which is typically followed by very low incidence in subsequent years. Screening endoscopy reduces colorectal cancer (CRC) incidence but the time course and magnitude of effects beyond 10 years after screening are unknown. We aimed to estimate the expected time course and magnitude of longterm impact of screening endoscopy on CRC incidence
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
