Effect of colonoscopy on colorectal cancer incidence and mortality: an instrumental variable analysis
Gastrointestinal Endoscopy, 06/21/2012
Jacob BJ et al. – Increased use of colonoscopy procedures is associated with a reduction in the incidence and mortality of colorectal cancer (CRC) in the population studied.Methods
- This study involved average-risk persons aged 50 to 74 years from 1996 to 2000 who were alive and free of CRC on January 1, 2001.
- Colonoscopy between 1996 and 2000.
- CRC incidence and mortality from 2001 to 2007.
- The study cohort contained 1,089,998 persons, 7.9% of whom had undergone a colonoscopy between 1996 and 2000.
- Using primary care physician rate of discretionary colonoscopy as an instrumental variable, the receipt of colonoscopy was associated with a 0.60% (95% confidence interval [CI], 0.31%-0.78%) absolute reduction in the 7-year colorectal cancer incidence and a 0.17% (95% CI, 0.14%-0.21%) absolute reduction in the 5-year risk of death caused by CRC.
- This corresponds to a 48% relative decrease in CRC incidence (risk ratio [RR] 0.52; 95% CI, 0.34-0.76) and 81% decrease in mortality caused by CRC (RR 0.19, 95% CI, 0.07-0.47).
- In subgroup analyses, the reduction in the risk of death due to CRC was larger in women than men.
- The reduction in CRC incidence was larger for complete colonoscopies and for left-sided cancers.