What is Colorectal Cancer?

  • Colorectal cancer (also known as colon cancer) is cancer of the colon and/or rectum and occurs when a growth in the lining of the colon or rectum becomes cancerous.
  • The colon is a vital organ in your body’s digestive system. The rectum is the very end of the colon. The colon and rectum,known as the large intestine, is a long,thick tube that:
    • Takes in water and minerals from digested food.
    • Stores undigested solid waste.
  •  Most colorectal cancers come from precancerous polyps — adenomatous polyps or serrated polyps — that form over a number of years (five to 10) to become a cancer.
  •  A polyp is a mushroom-like or flat growth on the inside wall of the colon or rectum. Polyps grow slowly over many years.
  •  Not all colon polyps have the same risk of turning into colon cancer.
    Precancerous polyps could become cancerous; other types of polyps (hyperplastic,inflammatory) do not.
  •  If caught early before any symptoms arise, surgery can cure colorectal cancer.Finding colorectal cancer early leads to easier treatments and higher survival rates.

Who Gets Colorectal Cancer?

  • As of 2015, colorectal cancer is the third-most common cause of cancer in both men and women. It is the second-leading cause of cancer deaths in the U.S.
  •  While men and women have the same lifetime risk for CRC, men are at higher risk than women at any given age.
  •  Many people do not get polyps until after the age of 50.
  •  People with a higher risk of getting colorectal cancer often get polyps before the age of 50.
  •  To lower the chance of colorectal cancer, it is vital to get screened at the right time.
    • If you are at average risk, start screening at age 50.
    • If you think you might be at high risk for colorectal cancer, talk to your doctor early, before age 50, to make a screening plan that’s right for you.

Colon Cancer Screening Can Save Your Life

  •  With routine colorectal cancer screening, more than one-third of colorectal cancer deaths can be avoided.
  •  Many tests can help find precancerous and cancerous growths. Finding them early could save your life.
  •  Colorectal cancer screening is safe and effective.
  •  Finding and getting rid of colon polyps prevents colon cancer, no matter what your risk is.
  •  With simple steps, you can lower your risk of getting the disease. Talk to a gastroenterologist.

Check out AGA’s informative videos on colorectal cancer screening. Learn about why it’s important to get screened, screening options and tips to ensure a high-quality colonoscopy.

Symptoms of Colorectal Cancer

Colorectal cancer mostly starts with no symptoms at all, which is why routine screening beginning at age 50 for all normal-risk individuals is so important.

Over time, though, there are a number of warning signs that can happen, such as:
• Rectal bleeding.
• Blood in your stool (bright red, black or very dark).
• Temporary change in your bowel movements, especially in the shape of the stool (e.g., thin like a pencil).
• Pain in having a bowel movement or the urge to move your bowels without having a bowel movement.
• Frequent cramping pain in your lower belly.
• Frequent gas pains.
• Weight loss without dieting.

What should I do if I have these symptoms?

If you are having any of the above symptoms, especially if you are at risk of colorectal cancer, call your gastroenterologist or primary-care physician right away. He or she will ask questions about your symptoms and figure out the best diagnostic test for you.

I feel fine. Why not wait for these symptoms to develop, rather than have a colonoscopy?


• Colorectal cancers found in patients with symptoms are more advanced and less likely to be cured.

• Colorectal cancers found in people without symptoms are not as advanced and more frequently cured.

• Precancerous polyps usually cause no symptoms, and removal of these polyps prevents colon cancer.

Risk Factors for Colorectal Cancer

You may be at normal or greater risk for colorectal cancer, based on your age, personal medical history and family medical history.
You are at normal risk for colorectal cancer if you are age 50 or older and have none of these risk factors:

  •  Have had colorectal cancer or precancerous polyps before.
    • A polyp is a mushroom-like growth on the inside wall of the colon or rectum. Polyps grow slowly over many years. Some polyps become cancerous; others
    do not.
  •  Have had one or more parent, brother or sister, or child who has had colorectal cancer or polyps.
  •  Have had family members with cancers, such as colorectal cancer or cancer in the uterus, ovary or other organs.
  •  Have (or have had) inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn’s disease.
  •  Have Lynch syndrome (hereditary non-polyposis
    colon cancer), which does not have a large number of polyps as a warning sign but often involves a family history of colorectal cancer among multiple family members in many generations.
  •  Have a syndrome, such as familial adenomatous polyposis (FAP), which leads to hundreds of polyps in the colon or rectum during the teen years; often one of these grows into cancer by age 30.

Talk to your doctor about your risk factors and when it is best to start screening.

Getting Tested for Colorectal Cancer

There are many choices of tests to get screened for colorectal cancer (CRC).

Visit www.gastro.org/patient-care,and talk to your gastroenterologist to find out which test is best for you.

Available Screening Options


  • 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.
  • 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.

o 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!

Prevention of Colorectal Cancer

Along with getting tested regularly, healthy life choices are usually recommended as the best way to lower your risk of colorectal cancer.

Here’s how you can help lower your risk:

  •  Do not smoke.
  •  Eat more foods that are high in fiber, such as whole grains, fruits and veggies.
  •  Eat more cruciferous veggies, such as cabbage, broccoli, cauliflower and brussels sprouts.
  •  Raise calcium intake with low-fat milk, shellfish, salmon and calcium supplements with vitamin D.
  •  Eat less fats, oils, butter and red meat.
  •  Limit your intake of charcoal-broiled foods, and skip salt-cured foods.
  • Get active.
  •  Keep your weight in the normal range.
  •  Limit alcohol intake.