Colon Cancer Screening

Colon Cancer Screening

Congratulations for taking an important step toward staying healthy!

Who Needs Screening?

Colon cancer doesn't develop overnight. It takes years to decades for normal cells that line the lower intestine to transform into cancer. Before the emergence of full-blown cancer, these cells must first evolve into growths called polyps. Screening for colon cancer works by detecting and removing these polyps before they become deadly.

Any person can get colon cancer. In fact, one in 20 people will develop colon cancer during their lifetime. Your biggest risk for colon cancer is simply getting older. That's why the National Cancer Institute and the American Cancer Society recommend colon cancer screening for all adults over 45.

Options for Getting Screened

There are several different ways to get screened for colon cancer. You may be aware of some of these tests, but many people don't realize that they can choose between different options. While experts think that some of these screening tests may be better than others, any test to screen for colon cancer is better than no test at all. Getting regular screening may lower your risk of colon cancer by more than half.

Many people need help deciding which screening test makes the most sense for them. Other people maybe confused about how often they need to have follow-up screening. This tool is designed to help you answer some of these important questions. However, keep in mind that this tool cannot substitute for the important conversations that you have with your health care provider. If you have questions or concerns, be sure to speak directly with your doctor.

A Decision Guide That Helps You Choose

This guide works by asking you to answer a series of questions related to your medical history, your preferences about your health care, and your information needs. None of this information is stored, saved, or transferred to anyone else. Once you leave this guide, all answers are discarded and cannot be retrieved.

Let's get started. Some people think they need a screening test when they develop symptoms. Not so. Screening tests are advised for people without any symptoms related to the health condition under consideration. Certain symptoms related to the colon and rectum may require urgent evaluation.

Have you had any of the following symptoms

  • blood in the stool (bowel movement), in the toilet bowl or on the toilet paper

  • abdominal pain

  • unexplained weight loss

  • a change in your bowel habits such as new constipation or diarrhea

  • unexplained anemia or iron deficiency?

Yes, I have one or more of these symptoms.

No, I do not have any symptoms.

If you do not have any special risk factors for colon cancer, you are considered to be at "average" risk. However, screening is still important. Keep in mind that most people diagnosed with colon cancer do not have any special risk factors.

The next step is to determine if you have been screened for colon cancer in the past. People who have had recent screening may not need repeat screening right away.

Common screening tests include stool tests, flexible sigmoidoscopy, colonoscopy, and virtual colonoscopy (CT scan).

Have you ever had one of these colon cancer screening tests?

Yes, I've been screened for colon cancer before.

No, I've never been screened for colon cancer.

Now is a great time to get screened!

The risk for colon cancer generally starts to rise after age 45. Almost everyone over age 45 should have regular screening for colon cancer. Screening is one of the best ways to lower your risk of developing this common and deadly form of cancer.

There are several different tests that can be used to screen for colon cancer. Each test has its own advantages and disadvantages. There is no "right" test for colon cancer. Keep in mind that any type of screening is better than no screening at all.

Please continue with the guide to choose a colon cancer screening test that makes the most sense for you.

I'd like some help choosing the option that's right for me.

Some people are worried that getting screened for colon cancer will be uncomfortable or that the tests have unacceptable risks.

What matters most to you when choosing a test?

I prefer a test that has a low risk of complications.

I prefer a test that causes little or no discomfort.

Stool tests are easy and safe. They can be completed at home. However, keep in mind that abnormal results from stool cards will usually require follow-up testing with colonoscopy.

Flexible sigmoidoscopy and virtual colonoscopy have low risks of complications.

After a normal colonoscopy, you can wait as long as ten years before your next colon cancer screening test.

Flexible sigmoidoscopy needs to be repeated every five years.

Stool cards (fecal occult blood tests) can be completed quickly at home.

However, keep in mind that abnormal results from stool tests will usually require follow-up testing with colonoscopy.

Colonoscopy is the most accurate test for detecting colon cancer and precancerous colon polyps. Studies suggest colonoscopy finds more than 90 percent of cancers and important polyps. Your doctor can also remove worrisome polyps at the same time that you are screened for cancer.

Slightly less accurate alternatives to colonoscopy include

  • virtual colonoscopy

  • flexible sigmoidoscopy combined with stool tests.

Congratulations on having been screened for colon cancer. Screening is one of the best ways to lower your risk of developing this common and deadly type of cancer.

Since colon cancer can develop at any time, screening needs to be repeated on a regular basis. The timing and type of your next screening test depends on whether your previous screening was normal, and what type of screening test you had. For example, people who have been diagnosed with certain types of colon polyps should have a follow-up colonoscopy every three to five years.

What was the result of your last colon cancer screening test?

My last screening test was normal.

My last screening test was not normal.

Most abnormal screening tests for colon cancer require follow-up. Contact your doctor if you are not sure what kind of abnormality you had on your last screening test. You may need additional testing.

Knowing what types of polyps you've had is important, since only certain types of polyps increase your risk for colon cancer. You can request information from your doctor (for example, a colonoscopy report or pathology report) to help answer this question.

Hyperplastic polyps are always benign. They do not have the potential to become cancerous. People who are found to have only hyperplastic polyps do not need special follow-up.

In the future, you may choose repeat colonoscopy or one of several different tests to screen for colon cancer. Each test has its own advantages and disadvantages. There is no "right" test for colon cancer. Keep in mind that any type of screening is better than no screening at all.

Please continue with the guide to choose a colon cancer screening test that makes the most sense for you.

I'd like some help choosing the option that's right for me.

People with risk factors for colon cancer may require more frequent screening or screening that begins at an earlier age.

Please choose your risk factor for colon cancer:

I have had colon cancer or colon polyps in the past.

One or more family members have had colon cancer or polyps.

I have been diagnosed with inflammatory bowel disease.

I may have a family cancer syndrome.

People with longstanding inflammatory bowel disease, such as Crohn's disease or ulcerative colitis, are at high risk for developing colon cancer. This risk of colon cancer goes up over time. Most people who have had inflammatory bowel disease for longer than eight years will need a colonoscopy every one to two years, indefinitely. You should consult with your doctor for a specific recommendation. Work with your health care providers to make sure that your screening is performed on a regular basis.

Having two or more close family members diagnosed with colon cancer raises your risk of colon cancer. This risk is higher with first-degree family members (father, mother, sister or brother) than with second-degree family members (grandparent, aunt, uncle, or cousin).

Which members of your family were diagnosed with colon cancer or polyps?

Two or more first-degree relatives

One first degree relative or two or more second-degree relatives

Your risk of colon cancer is moderately increased if two or more first-degree relatives (father, mother, sister or brother) were diagnosed with colon cancer or colon polyps. You should have your first colonoscopy at age 40, or at least ten years before the age at which the youngest family member was diagnosed. Colonoscopy should be repeated every five years.

You have a modestly increased risk of colon cancer. You should have your first colonoscopy at age 40. If this examination is normal, colonoscopy can be repeated on a routine schedule (every ten years).

People who develop colon cancer and certain types of colon polyps are at increased risk for developing pre-cancerous polyps in the future. They are also at risk for developing full-blown colon cancer -- even a second time. It's therefore important to have regular screening to find and remove polyps before they become cancerous.

Your risk of polyps and cancer depends on your particular situation.

Choose the statement that describes your history:

I have been diagnosed with colon cancer in the past.

I have been diagnosed with colon polyps in the past.

Knowing what types of polyps you've had is important, since only certain types of polyps increase your risk for colon cancer. You can request information from your doctor to help answer this question. A pathology report (microscopic examination of the polyp that was removed) will be most helpful.

If you cannot find information that tells you what types of polyps you've had, it probably makes sense to have a full colonoscopy three to five years after your most recent examination. You can talk to your doctor about a specific plan for follow-up.

Hyperplastic polyps are always benign. They do not have the potential to become cancerous. People who are found to have only hyperplastic polyps do not need special follow-up.

In the future, you may choose repeat colonoscopy or one of several different tests to screen for colon cancer. Each test has its own advantages and disadvantages. There is no "right" test for colon cancer. Keep in mind that any type of screening is better than no screening at all.

Please continue with the guide to choose a colon cancer screening test that makes the most sense for you.

I'd like some help choosing the option that's right for me.

If you think you had another screening test for colon cancer, check with your doctor for a recommendation about repeat testing.

Stool cards (fecal occult blood tests) are a good test to screen for colon cancer. Your chance of detecting colon cancer can be increased by combining stool cards with flexible sigmoidoscopy or barium enema.

Stool cards need to be repeated every one to two years to be effective. Alternatively, you can choose between several different tests, including

  • colonoscopy

  • computed tomography, also called "virtual" colonoscopy

  • flexible sigmoidoscopy

  • barium enema.

Colonoscopy is one of the best ways to screen for colon cancer. People who have a normal colonoscopy have a very low risk of developing colon cancer in the following decade.

Most experts believe that after a normal colonoscopy, you can wait ten years before your next colon cancer screening test. At that point, you can choose between several different tests, including

  • repeat colonoscopy

  • computed tomography, also called "virtual" colonoscopy

  • flexible sigmoidoscopy

  • stool cards (fecal occult blood tests)

  • barium enema.

People who have been diagnosed and treated for colon cancer usually have a complete bowel examination (colonoscopy) as part of their evaluation. If you did not have a colonoscopy prior to your treatment, this should be completed with six months of your diagnosis.

Even if you have had a normal colonoscopy, you will still need periodic examinations to ensure that cancer and pre-cancerous polyps have not returned. A typical schedule for follow-up examinations would include

  • a colonoscopy one year after your diagnosis, followed by

  • a repeat colonoscopy in three additional years, then

  • screening colonoscopy every three to five years indefinitely.

Be sure to speak with your doctor if you have missed any of these follow-up examinations, or if you have general questions about your diagnosis of colon cancer.

To continue reading this article, you must log in.

Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.

  • Research health conditions
  • Check your symptoms
  • Prepare for a doctor's visit or test
  • Find the best treatments and procedures for you
  • Explore options for better nutrition and exercise
Learn more about the many benefits and features of joining Harvard Health Online »

I'd like to receive access to Harvard Health Online for only $4.99 a month.

Sign Me Up

Already a member? Login ».

Disclaimer:

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.