Screening tests are important in finding polyps before they become cancerous. These tests also can help find colorectal cancer in its early stages, when you have a good chance of recovery.

Screening methods include:

  • Colonoscopy, in which a small tube with a light and camera is inserted into your rectum to look at your colon. If polyps are found, your health care provider may remove them immediately or take tissue samples to send to the lab for analysis.
  • Virtual colonoscopy, a test that uses a CT scan to view your colon. Virtual colonoscopy requires the same bowel preparation as a colonoscopy. If a polyp is found during the scan, you'll need to repeat the bowel preparation for a colonoscopy to have the polyp examined and removed.
  • Flexible sigmoidoscopy. Like a colonoscopy, this uses a small tube with a light and camera but examines just the last third of your colon, called the sigmoid. Most of the colon is not seen with this screening test, so some polyps and cancers may not be found.
  • Stool-based tests. These tests check for blood in the stool or assess your stool DNA for evidence of a colon polyp or cancer. If your stool test is positive, you will need a colonoscopy soon afterward.


Your health care provider is likely to remove all polyps discovered during a bowel exam. The options for removal include:

  • Polypectomy. In the early stage when they are smaller, polyps can be removed by putting a tube with a tool in the rectum and cutting the cancer out.
  • Minimally invasive surgery. Polyps that are too large or that can't be removed safely during screening are usually removed surgically. This is often done by inserting an instrument called a laparoscope into the abdomen to remove the cancerous part of the bowel.
  • Total proctocolectomy. If you have a rare inherited syndrome, such as FAP, you may need surgery to remove your colon and rectum. This surgery can protect you from developing a life-threatening cancer.

Some types of colon polyps are more likely to become cancerous than others. A health care provider who analyzes tissue samples will look at your polyp tissue under a microscope to determine if it could be cancerous.

Follow-up care

If you have had an adenomatous polyp or a serrated polyp, you are at increased risk of colon cancer. The level of risk depends on the size, number and characteristics of the adenomatous polyps that were removed.

You'll need follow-up screenings for polyps. Your health care provider is likely to recommend a colonoscopy:

  • In 5 to 10 years if you had only one or two small adenomas.
  • In 3 to 5 years if you had three or four adenomas.
  • In three years if you had 5 to 10 adenomas, adenomas larger than 10 millimeters or certain types of adenomas.
  • Within six months if you had multiple adenomas, a very large adenoma or an adenoma that had to be removed in pieces.

Preparing for your colonoscopy

It's very important to fully clean out your colon before a colonoscopy. If stool remains in the colon and blocks your health care provider's view of the colon wall, you will likely need another colonoscopy sooner than usual to make sure all polyps are found.

After a good colon preparation, bowel movements should appear as clear liquid. They may be slightly yellow or green-tinged, depending on any liquids consumed while preparing. If you experience trouble with your colon preparation or feel that you have not been fully cleaned out, you should tell your provider before beginning your colonoscopy. Some people need additional steps before having a colonoscopy.

Preparing for your appointment

You may be referred to a health care provider who specializes in digestive diseases, called a gastroenterologist.

What you can do

  • Be aware of any pre-appointment restrictions, such as not eating solid food on the day before your appointment.
  • Write down your symptoms, including any that may seem unrelated to the reason why you scheduled the appointment.
  • Make a list of all your medications, vitamins and supplements.
  • Write down your key medical information, including other conditions.
  • Write down key personal information, including any recent changes or stressors in your life.
  • Ask a relative or friend to accompany you to help you remember what the health care provider says.
  • Write down questions to ask your provider.

Questions to ask your doctor

  • What's the most likely cause of my symptoms?
  • What kinds of tests do I need? Do these tests require any special preparation?
  • What treatments are available?
  • What are the chances these polyps are malignant?
  • Is it possible that I have a genetic condition leading to colon polyps?
  • What kind of follow-up testing do I need?
  • Should I remove or add any foods to my diet?
  • I have other health conditions. How can I best manage these conditions together?

In addition to the questions that you've prepared to ask your health care provider, don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your provider is likely to ask you a number of questions. Being ready to answer them may leave time to go over points you want to spend more time on. You may be asked:

  • When did you first begin experiencing symptoms, and how severe are they?
  • Have your symptoms been continuous or occasional?
  • Have you or has anyone in your family had colon cancer or colon polyps?
  • Has anyone in your family had other cancers of the digestive tract, the uterus, the ovaries or the bladder?
  • How much do you smoke and drink?