Related Experiment Video
Updated: Oct 3, 2026

Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System
Published on: October 16, 2013
Screening endoscopy and risk of colorectal cancer in United States men
A M Kavanagh1, E L Giovannucci, C S Fuchs
1Anti-Cancer Council of Victoria, Australia.
Objectives:
The purpose of this study was to describe the effect of screening endoscopy (sigmoidoscopy or colonoscopy) on colorectal cancer incidence and mortality.
Methods:
We used data from a prospective cohort study of 24,744 men aged 40 to 75 years in 1986, free from cancer and colon polyps, followed until 1994. The outcomes are diagnosis of colorectal cancer and death from colorectal cancer.
Results:
Screening endoscopy in 1986-87 was associated with a lower risk of all colorectal cancer (multivariate relative risk [RR] = 0.58, 95 percent confidence interval [CI] = 0.36-0.96); cancer in the distal colon or rectum (multivariate RR = 0.40, CI = 0.19-0.84); Dukes stage A&B (multivariate RR = 0.66, CI = 0.35-1.25); and Dukes stage C&D (multivariate RR = 0.50, CI = 0.20-1.26) colorectal cancer; and death from colorectal cancer (multivariate RR = 0.56, CI = 0.20-1.60), after adjusting for age and a wide range of colon cancer risk factors. Screening endoscopy in 1988-87 appeared to provide strong protection against distal stage C&D cancers (age-adjusted RR = 0.16, CI = 0.02-1.23) but no protection against proximal stage C&D cancers (age-adjusted RR = 0.96, CI = 0.32-2.91).
Conclusions:
This study provides strong evidence for a protective effect of screening sigmoidoscopy on colorectal cancer incidence and mortality and supports recommendations for screening sigmoidoscopy as an approach to colon cancer prevention.
Related Concept Videos
Cancer Prevention
Some...
Barrett Esophagus-I: Introduction
This constant acid exposure transforms the esophagus's pink mucosal lining (stratified squamous epithelium) into a type of lining more similar...
Endoscopic Procedures I: Esophagogastroduodenoscopy
During an EGD, the endoscope can be used to:
Endoscopic Procedures II: Colonoscopy
Endoscopic Procedures III: Video Capsule Endoscopy
Endoscopic Procedures IV: Sigmoidoscopy and Laproscopy
Sigmoidoscopy
Sigmoidoscopy is a diagnostic procedure that uses a flexible sigmoidoscope equipped with a light source and camera to examine the rectum and sigmoid colon. The procedure involves inserting the tube through the anus...

