There are several ways to screen for colorectal cancer, including:
The doctor inserts a flexible, lighted tube called a colonoscope into the colon through the anus during a colonoscopy. Polyps and cancer can be detected throughout the colon by the doctor.
A sigmoidoscopy uses a flexible, lighted tube called a sigmoidoscope to examine the lower colon for polyps and cancer. This test cannot be used to check the upper part of the colon.
FOBTs detect small amounts of blood in faeces or stool, which may indicate polyps or cancer.
An x-ray of the colon is taken during a double contrast barium enema. In x-rays, the barium dye helps highlight the outline of the colon. This test can be used to screen people who cannot have a colonoscopy.
CT (computed tomography) colonography is a test that uses CT scans to check the large bowel (colon) and back passage (rectum). It’s also called a virtual colonoscopy.