NPS
National Polyp Study: colonoscopic polypectomy and colorectal cancer incidence and mortality
Phase observationalN = 1,418
- Population
- 1993 report: 1,418 people with adenomas removed at colonoscopy. 2012 report: 2,602 people with adenomas removed.
- Design
- Prospective cohort of people who had one or more adenomas removed during complete colonoscopy and then had periodic surveillance colonoscopy. The 1993 report compared colorectal cancer incidence with that expected from three reference groups (two cohorts in which polyps were not removed and one general-population registry), adjusted for sex, age and polyp size. The 2012 report (people referred for initial colonoscopy between 1980 and 1990) used the National Death Index, with follow-up up to 23 years, and compared colorectal cancer mortality with that expected in the general population (SEER) and with people who had non-adenomatous polyps. The 1,418 people of the 1993 report were enrolled in a randomised trial of surveillance-colonoscopy intervals; the 2012 cohort of 2,602 includes them (Zauber 2012 full text, Methods and Results).
- Arms
- Adenomas removed at colonoscopy (experimental, n = 1,418): Colonoscopic removal of adenomas followed by periodic surveillance colonoscopy
- Reference rates (control): Expected colorectal cancer incidence or mortality from reference groups in which polyps were not removed, and from general-population registry rates
- People
- Winawer SJ, The National Polyp Study Workgroup