2016-06-16 17:35:27 UTC

Colorectal Cancer (CRC) 104: Getting Tested

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There are many choices of tests to get screened for colorectal cancer (CRC). Talk to your gastroenterologist to find out which test is best for you. 

 

Available Screening Options

 

Colonoscopy

  • A colonoscopy involves looking at the colon from inside the body using a long, thin (about the width of your little finger), flexible tube with a tiny camera on the end, through which the doctor can view your whole colon and rectum for polyps or cancer.
    • If the doctor sees any polyps during a colonoscopy, he or she will remove them right away, during the procedure. 
    • You will not be able to feel a polyp being removed and removing them will not impact your recovery time. 
    • Removing polyps during a colonoscopy could stop colon cancer from growing or even cure it.
  • This test can be done in an outpatient surgical center, an outpatient office or a hospital setting. You do not have to stay in the hospital overnight.
  • You will need to “prep” before this test, meaning get your body ready with a special liquid diet and laxatives.
  • You may be given medicine to make you relaxed and sleepy during this test. 
  • You might feel some pressure during the exam, and there may be some cramping afterwards, but you most likely will not feel anything during this test. 
  • It is the only method that blends both testing and prevention (by getting rid of polyps that could lead to cancer).

How often do you need a colonoscopy? 

  • Every 10 years after age 50 for normal-risk people. 
  • Patients at higher risk for colorectal cancer, including those with a family history or with polyps or other illnesses, should talk to a gastroenterologist about when to start screening and how often to be screened. 

How do you get ready for a colonoscopy?

  • Your doctor will order you to be on a clear-liquid diet the day before your test
  • Laxatives and/or enemas will be needed to help clean out your colon to give your gastroenterologist a clear view.
  • If you get medicine to make you relaxed and sleepy, you will need someone to take you home and you won’t be able to go to work or drive a motor vehicle that day. The following day, most people resume their usual activities.

Fecal Immunochemical Test (FIT)

  • The FIT test comes in a kit with which you can collect your stool samples at home in a special container. Your doctor’s office will instruct you about how to perform the test. 
  • FIT is a test that can find hidden, invisible blood in the stool.
  • FIT is low cost and pretty easy to do
  • You do not have to follow a special diet or “prep” for this test.
  • It can find many early cancers but only the largest precancerous polyps. 
  • If the FIT test detects hidden blood in your stool, you will need to discuss further testing with your doctor. Usually a colonoscopy is recommended.

How often do you need a FIT test?

  • Annually (every year) for persons starting at age 50. 

How do you get ready for a FIT test? 

  • The FIT test does not call for a special diet or preparation.
  • The FIT test is available without a prescription.

Fecal Occult Blood Test (FOBT)

  • The test comes in a kit with which you can collect the stool samples at home in a special container and then send them to a lab so they can look for blood in your stool.
  • Stool is tested in a lab for hidden blood that you cannot see.
  • You will need to follow a special diet before doing this test.
  • This test, which is pretty easy and low cost, is designed to test for early cancers, but it does not find precancerous polyps. 
  • If the FOBT is not normal, you will need to discuss further testing with your doctor. Usually a colonoscopy is recommended. 

How often do you need a FOBT test?

  • Annually (every year) for persons starting at age 50. 

How do you get ready for a FOBT test?

  • Do not eat or use these items for two days before the test, as they may change the test results:

    • Cauliflower
    • Cabbage
    • Horseradish
    • Radishes
    • Turnips
    • Red meat
    • Vitamin C supplements
    • Foods that have iron
    • Aspirin, which can irritate the stomach
    • NSAIDs
  • FOBT is available without a prescription.

Cologuard® (Stool DNA)

  • Cologuard is an at-home stool test, somewhat like the FIT or FOBT tests, that is only available by prescription.
  • You doctor orders the test straight from the lab, and the kit with the test is mailed from the lab to your home
  • You will collect your stool in the given container, which conveniently mounts on the toilet.
  • You will mail back your test to the lab using a prepaid shipping label.
  • Cologuard finds abnormal cell parts, DNA, from colon cancers and polyps and tests for blood in your stool. 
  • If Cologuard is not normal, you will need to discuss further testing with your doctor. Usually a colonoscopy is recommended.

How often do you need a Cologuard test? 

  • Every three years for persons starting at age 50. 

How do you get ready for a Cologuard test?

  • Cologuard does not call for a special diet or preparation.

Flexible Sigmoidoscopy

  • This test can be done in a doctor’s office and does not need anesthesia or sedation (medicine that makes you sleepy). 
  • Sigmoidoscopy is a test during which a doctor uses a short, thin (about the width of your little finger), flexible tube with a tiny camera on the end to check the rectum and the lower end of the colon for polyps and cancer. Only the final two feet of the colon’s six feet are examined.
  • Introduction of the flexible tube may be somewhat uncomfortable, and some cramping may happen during the test. 
  • You will need to take a couple of cleansing enemas before the test and/or a gentle oral prep.
  • You may be given medicine to make you relaxed and sleepy during this test. 
  • The doctor may take a biopsy (a small piece of tissue to look at under a microscope). This is done during the test and is not something you will be able to feel
    • If a biopsy is done, you may see some traces of blood in your stool for a few days after the test. It will not impact your recovery.
  • After the test, there may be some mild belly-gas pains. 
  • If a polyp or abnormality is found, you may need a colonoscopy. 

How often do you need a flexible sigmoidoscopy?

  • Every five years starting at age 50 if annual stool tests for blood are negative.

How do you get ready for a flexible sigmoidoscopy?

  • One or two mild enemas are given before the test.

Computed Tomographic (CT) Colonography

  • This test can be done in an imaging center, outpatient office or a hospital. 
  • This test will look at your colon and rectum using a special machine to take pictures. 
  • At the start of the test, a small, flexible tube will be put into your rectum to pump air into your colon. 
  • A machine is used to combine the pictures, making both 2- and 3-dimensional views that allow a trained doctor to look for polyps and cancer. 
  • You do not need to be put to sleep for this test, but you may feel the air that is put in your colon
  • You will need to clean out your colon before the test, just like for a colonoscopy.
  • If a polyp is found during this test, you will need a colonoscopy.

How often do you need a CT colonography?

  • Every five years for average-risk people. 
  • Patients at higher risk for colorectal cancer, like those with a family history or with polyps or other health problems, should talk to their gastroenterologist about whether a colonoscopy would be a better option.
  • If your colonoscopy was unsuccessful in seeing your entire colon due to technical or anatomical reasons.

How do you get ready for a CT colonography?

  • Preparation for a CT colonography is the same as for a colonoscopy.
  • You will need to be on a special diet, usually clear liquids, the day before your test. 
  • Laxatives and/or enemas will be needed to clean out your colon. 
  • You should check with your health plan to see if they will pay for this test.

Digital Rectal Examination

  • This is when your doctor places a finger inside your rectum.
  • Sometimes, the doctor will collect a bit of stool to look at from this exam.
  • A rectal exam in the doctor’s office is not acceptable for screening for colorectal cancer. 


Please work with your doctor to determine the best screening options for you. Be open and honest about symptoms, concerns and questions. Remember, colorectal cancer screening has been demonstrated to be lifesaving. No butts about it: Get screened!

 

© AGA, September 2017

©AGA, July 2016

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