Diagnosis

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 the rectum to look at the colon. If polyps are found, a healthcare professional may remove them right away or take tissue samples to send to a lab for analysis.
  • Virtual colonoscopy, a test that uses a CT scan to view the 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 the colon. Most of the colon is not seen with this screening test, so some polyps and cancers may not be found. When this test is used, it is repeated more often than colonoscopy or is used along with an annual stool-based test.
  • Stool-based tests. There are a few of these tests available. One of these checks for blood in the stool and needs to be repeated every year. Another test checks for blood and tumor markers in the stool to look for colon polyps or colorectal cancer and is repeated every three years. If any of the stool-based tests are positive, a colonoscopy is recommended soon afterward.

Treatment

A healthcare professional is likely to remove all polyps discovered during a bowel exam. Options for removal include:

  • Polypectomy. Polyps can be removed during colonoscopy using a few techniques. This process is called polypectomy. The removal of polyps prevents the opportunity for them to grow into colorectal cancer.
  • Minimally invasive surgery. Polyps that are too large or that can't be removed safely during colonoscopy are usually removed surgically. This is often done by placing an instrument called a laparoscope into the abdomen to remove the part of the bowel with the polyp or cancer.
  • 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 colorectal cancer.

Some types of colon polyps have the potential to become cancerous and others don't. A medical professional who studies tissue samples, called a pathologist, will look at the polyp tissue under a microscope to find out.

Follow-up care

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

A healthcare professional is likely to recommend a colonoscopy:

  • In 7 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.
  • In 6 months to one year if you had more than 10 adenomas, a very large adenoma or an adenoma that had to be removed in pieces.
  • The follow-up colonoscopy schedule for serrated lesions is like those for adenomas.

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 the 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 the health professional before beginning your colonoscopy. Some people need additional steps before having a colonoscopy.

Preparing for your appointment

You may be referred to a healthcare professional 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 medicines, 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 care professional says.
  • Write down questions to ask during the appointment.

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, don't hesitate to ask other questions during your appointment.

What to expect from your doctor

You'll likely be asked a few 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 colorectal 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?
By Mayo Clinic Staff