Abstract
Objectives:Colonoscopy is widely recommended for colorectal cancer (CRC) screening, but evidence to guide the optimal frequency of repeat screening examination is limited. We examined the duration and magnitude of the risk of developing CRC, following a negative colonoscopy in those at average risk and those with a first-degree family history of CRC.Methods:A cohort of Utah residents aged 50-80 years who had a negative colonoscopy between 1 January 2001 and 31 December 2011 was identified using the Utah Population Database. Patients were followed from the time of the index colonoscopy until diagnosis of CRC, death, migration out of state, repeat colonoscopy, or end of the study period. CRC incidence after the index colonoscopy was compared with that of the state population by standardized incidence ratios (SIRs).Results:A cohort of 131,349 individuals at average risk with a negative colonoscopy was identified. Compared with the state population, a negative colonoscopy was associated with SIRs of 0.15 (95% confidence interval (CI): 0.08-0.23) at 1 year, 0.26 (95% CI: 0.19-0.32) at 2-5 years, 0.33 (95% CI: 0.22-0.43) at 5-6 years, and 0.60 (95% CI: 0.44-0.76) at 7-10 years for CRC following the index colonoscopy. In a secondary analysis involving only patients with a first-degree relative with CRC, patients had a significantly lower incidence of CRC only for the first 5 years of follow-up (SIR 0.39, 95% CI: 013-0.64). There was also a difference in the risk of proximal (SIR 0.72, 95% CI: 0.45-0.98) and distal (SIR 0.51, 95% CI: 0.30-0.72) colon cancers at 7-10 years following a negative colonoscopy.Conclusions:The risk of developing CRC remains decreased for at least 10 years following the performance of a negative colonoscopy. However, the lower incidence of CRC in those with a family history of CRC differed in magnitude and timing being limited primarily to the first 5 years of follow-up and of lesser magnitude than that in the overall cohort.
| Original language | English |
|---|---|
| Pages (from-to) | 1439-1447 |
| Number of pages | 9 |
| Journal | American Journal of Gastroenterology |
| Volume | 112 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 1 2017 |
| Externally published | Yes |
Funding
Guarantor of the article: N. Jewel Samadder, MD, MSc, FRCPC. Specific author contributions: N.J.S. and R.W.B. had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analyses. Study concept and design (R.W.B., K.C., and N.J.S.); acquisition, analysis, and interpretation of data (K.R.S., K.C., H.H., A.F., Y.W., K.M.B., L.P., R.W.B., and N.J.S.); drafting of the manuscript (N.J.S.); critical revision of the manuscript for important intellectual content (K.C., H.H., K.R.S., R.W.B., and L.P.); statistical analysis (A.F., Y.W., L.P., and K.M.B.); obtained funding (N.J.S. and R.W.B.). Financial support: The study was funded by the National Cancer Institute, American Society for Gastrointestinal Endoscopy, American College of Gastroenterology, and the Huntsman Cancer Foundation. Support for this project was provided by NCI grants P01-CA073992 (R.W.B.), R01-CA040641 (R.W.B.), an Endoscopic Research Award from the American Society for Gastrointestinal Endoscopy (N.J.S.), and a junior faculty career development award from the American College of Gastroenterology (N.J.S.). Partial support for the Utah Population Database, the Cancer Biostatistics Shared Resource, and this project was provided by the Huntsman Cancer Institute Cancer Center Support Grant P30CA042014 from the National Cancer Institute and the Huntsman Cancer Foundation. Support for the UCR is provided by Contract HHSN 261201000026C from the National Cancer Institute, with additional support from the Utah Department of Health and the University of Utah. The funding sources did not play a role in the design, conduct, or reporting of the study or in the decision to submit the manuscript for publication. Potential competing interests: R.W.B. is a consultant for Myriad Genetics and N.J.S. is a consultant for Cook Medical. The other authors declare no conflict of interest.