Endoscopic screening for colorectal cancer: recent studies from Indiana University

Fecal occult blood testing is inadequate as a sole screening measure for colorectal cancer. Endoscopic screening and adenoma removal is now proven to reduce colorectal cancer mortality. At the Indiana University Colorectal Cancer Screening Center, studies have clarified several issues regarding endoscopic screening for colorectal cancer. Screening colonoscopy in 621 asymptomatic adults aged 50 to 75 years demonstrated that 27% had colonic adenomas. Increasing age and male gender were both powerful predictors of an increased prevalence of colonic adenomas. A family history of a single first-degree relative who developed colorectal cancer at age 60 or older did not predict a higher prevalence of colonic adenomas. All cancers and all adenomas greater than or equal to 1 cm in size found in average-risk persons were found in persons aged 60 or older. Half of the people with adenomas had no neoplasia within reach of the flexible sigmoidoscope. Based on these findings, we have suggested that a single screening colonoscopy performed in average-risk person in their early sixties may be an effective method to reduce colorectal cancer mortality. In the screening colonoscopy study, distal colonic hyperplastic polyps were shown to not predict proximal colon adenomas. Therefore, colonoscopy is not warranted when only hyperplastic polyps are detected by flexible sigmoidoscopy in asymptomatic, average-risk people. Screening sigmoidoscopic exams using colonoscopes showed that 60 cm scopes have the optimal length for flexible sigmoidoscopy in unsedated patients. Finally, a screening colonoscopy study demonstrated that women with a personal history of breast cancer do not have an increased prevalence of colonic adenomas.