Table 2.
Screening tests for colorectal cancer
| Stool test (FOBT) | Flexible sigmoidoscopy ‘flex sig’ | |
|---|---|---|
| What is this test? | The patient puts a small piece of stool on a test card. You do this for three bowel movements in a row and then return the cards to the doctor or lab. The samples are checked for blood, and if blood is found, it may mean there are polyps in the colon or rectum. | A doctor inserts a short, thin, flexible tube with a camera on the end into the rectum and looks for polyps in the rectum and lower third of the colon. |
| Where is it done? | At home | In a hospital or clinic. |
| How often is it done? | Every year | Every 5 years |
| What kind of preparation is there? | Certain foods (such as red meat) should not be eaten for approximately 3 days before the samples are taken. | Patients usually need to clean out the rectum and colon by using a laxative the night before and an enema the morning of the examination. |
| Are there any possible complications? | No | Complications are rare but some possibilities are: infection and small tears in the colon. |
| What happens if polyps are found? | If blood is found in the stool, a colonoscopy should be done to see if there are polyps in the colon or rectum. | A biopsy can be done If the biopsy shows a cancerous polyp, a colonoscopy must be done to remove the polyps. |
| How good is this test at finding cancer? | This test can show signs or symptoms of cancer, but cannot be used to find cancer. Also, many polyps do not bleed and, because of that, this test may show a false‐negative result. | This test can find polyps in the rectum and lower part of the colon, and samples of the polyps can be taken, but it cannot detect polyps in upper parts of the colon. |
| DCBE | Colonoscopy | |
| What is this test? | This is an X‐ray of the colon (but not the rectum). You are first given an enema with a liquid called barium. The doctor then takes an X‐ray. The barium makes it easy for the doctor to see the outline of the colon on the X‐ray to check for polyps. | A doctor inserts a long, thin flexible lighted tube into the rectum and the entire colon. The tube has a camera on the end to check for polyps. During this procedure, doctors can both find and remove polyps. |
| Where is it done? | In a hospital or clinic. | In a hospital or clinic |
| How often is it done? | Every 5–10 years. | Every 10 years. If polyps have been found previously, the test may be done more frequently. |
| What kind of preparation is there? | Patients need to clean out the rectum and colon completely for 1–3 days before the examination by taking special medicine or enemas. Patients cannot eat or drink anything for at least 1 day before and morning of the examination. | Patients need to clean out the rectum and colon completely for 1–3 days before the examination by taking special medicine or enemas. Patients cannot eat or drink anything for at least 1 day before and morning of the examination. During the examination patients are given medicine through a vein to sedate them (make them go to sleep). |
| Are there any possible complications? | Complications are rare but some possibilities are: infections, small tears in the colon, bleeding, fever and difficulty having a bowel movement. | Complications are rare but some possibilities are: infections and small tears in the colon. |
| What happens if polyps are found? | Samples of polyps cannot be taken A colonoscopy must be done to remove the polyps. | If polyps are found during the procedure, they are removed. |
| How good is this test at finding cancer? | This test can find polyps in the colon, but samples cannot be taken. This test may miss small polyps and sometimes even small cancers. | This test can find and remove polyps throughout the entire colon and rectum. |
DCBE, Double Contrast Barium Enema; FOBT, Fecal Occult Blood Test.