Colorectal Cancer Screening (PDQ®): Screening - Patient Information [NCI] - Colorectal Cancer Screening
Colonoscopy is a procedure to look inside the rectum and colon for polyps, abnormal areas, or cancer. A colonoscope is inserted through the rectum into the colon. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer.
Colonoscopy. A thin, lighted tube is inserted through the anus and rectum and into the colon to look for abnormal areas.
Studies have not shown that screening for colorectal cancer using digital rectal exam helps decrease the number of deaths from the disease.
A digital rectal exam (DRE) may be done as part of a routine physical exam. A digital rectal exam is an exam of the rectum. A doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual. Study results have shown that there is no evidence to support DRE as a screening method for colorectal cancer.
New screening tests are being studied in clinical trials.
Virtual colonoscopy is a procedure that uses a series of x-rays called computed tomography to make a series of pictures of the colon. A computer puts the pictures together to create detailed images that may show polyps and anything else that seems unusual on the inside surface of the colon. This test is also called colonography or CT colonography. Clinical trials are comparing virtual colonoscopy with commonly used colorectal cancer screening tests. Other clinical trials are testing whether drinking a contrast material that coats the stool, instead of using laxatives to clear the colon, shows polyps clearly.
DNA stool test
This test checks DNA in stool cells for genetic changes that may be a sign of colorectal cancer.
Screening clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site.