A colonoscopy. Your doctor uses a lighted scope to view the inside of your entire colon. Polyps can be removed during this test. A colonoscopy is recommended when another screening test shows that you may have colorectal cancer.4
A sigmoidoscopy. Your doctor uses a lighted scope to view the lower part of your intestine. Doctors can also remove polyps during this test.
A barium enema. A whitish liquid with barium is inserted through your rectum into your intestine. The barium outlines the inside of the colon so that it can be seen on an X-ray.
A biopsy. A sample of tissue is taken from the inside of your intestine and examined under a microscope. A doctor called a pathologist can look at the tissue sample and see if it contains cancer.
For people who have an increased risk for colorectal cancer, regular colonoscopy is the recommended screening test. It allows your doctor to remove polyps (polypectomy) and take tissue samples at the same time.
When you are diagnosed with colorectal cancer, your doctor may order other tests to find out if the cancer has spread. These tests include:
An MRI or PET scan to see if the cancer has spread into your chest or organs in the belly or pelvis.
An ultrasound to find the cause of belly pain or increased belly girth. It can also see if the cancer has spread to your liver. An endoscopic ultrasound is used to see how far rectal cancer may have spread.