Several types of screening tests can be used to find polyps and colon cancer. Talk with your doctor about which option is right for you. All men and women age 50-75 should get checked for colon cancer using one these tests:
Stool based screening tests
There are two types of stool based screening tests that check for blood in your stool. They are called FOBT (sensitive fecal occult blood test) and FIT (fecal immunochemical test). These tests should be done once a year. A positive test requires further testing. Click here for a one-page document on stool based screening.
These tests include the colonoscopy, flexible sigmoidoscopy, and virtual colonoscopy. These tests allow doctors to check for polyps and cancer. The colonoscopy is the only test that allows the doctor to check inside the entire colon and remove polyps.
More about the colonoscopy:
Colonoscopy is the single most reliable test for detection of polyps and cancer.Your doctor will examine the inside of your colon and rectum using a long, lighted tube called a colonoscope.Your doctor will check for abnormalities such as polyps. Generally, if a polyp is found, it can be removed with the scope. Removal of polyps is essential in prevention of colon cancer.A colonoscopy should be performed every 10 years in a normal risk person. If polyps are found during a colonoscopy or if the person is moderate or high risk for colon cancer, a more frequent evaluation may be needed. View diagram.
More about the Sigmoidoscopy:
The doctor will examine the rectum and only the lower portion of the colon with a lighted tube. If polyps are found, a complete colon exam, such as colonoscopy will be needed to further evaluate the possibility of other polyps in higher regions of your colon unable to be reached by sigmoidoscopy. View diagram.
More about the Virtual Colonoscopy:
Images of the colon and rectum are taken using computerized tomography (CT). A computer puts the images together to create an animated, three-dimensional view. If abnormalities are detected, a colonoscopy is necessary. View diagram.
When to get screened:
For average risk individuals, colonoscopy is recommended once every 10 years starting at age 50, and for African Americans at age 45 by several societies.
Higher levels of risk require more frequent testing intervals. If polyps (specifically a type of polyp called an adenoma) are found, then follow up surveillance with colonoscopy is recommended every 5 years.Shorter or longer intervals are dependent on the number, size, and character of the polyps identified.
For more detailed screening information, see the Colorectal Cancer Screening Tip Sheet.
For any structural test, good bowel prep is essential to safely and accurately identify polyps. The goal of prep is to eliminate all fecal matter from the colon so that the physician conducting the exam will have a clear view. Your physician will instruct you to ingest a particular prep medication, often tablets or a powder to be dissolved in water. If you have significant heart, liver, or kidney problems, ask your physician whether you need specifically tailored preps. Drinking lots of fluids helps avoid dehydration. All preparations will result in multiple bowel movements, so set aside the evening before your exam in a comfortable convenient location (near the bathroom).
If colonoscopy is not for you, then you do have options.