Colorectal (Colon) Cancer

Basic Information

Colorectal cancer is cancer that occurs in the colon or rectum Sometimes it is called colon cancer, for short. As the drawing shows, the colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus

Colorectal cancer affects both men and women of all racial and ethnic groups, and is most often found in people aged 50 years or older. For men, colorectal cancer is the third most common cancer after prostate and lung cancers. For women, colorectal cancer is the third most common cancer after breast and lung cancers.

Screening can find precancerous polyps-abnormal growths in the colon or rectum-so that they can be removed before turning into cancer. Screening also helps find colorectal cancer at an early stage, when treatment often leads to a cure

Symptoms

Colorectal cancer first develops with few, if any, symptoms. However, if symptoms are present, they may include:

• Blood in or on the stool
• A change in bowel habits
• Stools that are narrower than usual
• General, unexplained stomach discomfort
• Frequent gas, pains or indigestion;
• Unexplained weight loss
• Chronic fatigue

These symptoms can also be associated with many other health conditions. If you have any of these symptoms, discuss them with your doctor. Only your doctor can determine why you're having these symptoms.

Screening Saves Lives

Colorectal cancer almost always develops from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find precancerous polyps, so that they can be removed before they turn into cancer. Screening tests can also find colorectal cancer early, when treatment works best.

When Should I Begin to Get Screened?

You should begin screening for colorectal cancer soon after turning 50, then continue getting screened at regular intervals. However, you may need to be tested earlier or more often than other people if:
You or a close relative have had colorectal polyps or colorectal cancer; or
You have inflammatory bowel disease.

Speak with your doctor about when you should begin screening and how often you should be tested.

What Is Colorectal Cancer Screening?

Screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, are effective when they can detect disease early. Detecting disease early can lead to more effective treatment. In some cases, screening tests can detect abnormalities such as polyps, before they have a chance to turn into cancer. So removing polyps prevents colorectal cancer from developing.

Frequently Asked Questions

What is colorectal cancer?

Cancer is a group of diseases in which there is abnormal and uncontrolled growth of cells in the body. If left untreated, malignant (or cancerous) cells can spread to other parts of the body. "Colorectal" refers to the colon and rectum, which together make up the large intestine. Colorectal cancer can begin anywhere in the large intestine.

The majority of colorectal cancers begin as polyps-abnormal growths-inside the colon or rectum that may become cancers over a long period of time.

What causes colorectal cancer?

The exact cause of most colorectal cancers is not yet known. About 75% of colorectal cancers occur in people with no known risk factors. There are some known factors that may increase a person's risk of developing colorectal cancer, which include:
A personal or family history of colorectal polyps or colorectal cancer;
Inflammatory bowel disease (ulcerative colitis or Crohn's disease); or
Genetic syndromes such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC). (Just 5% of colorectal cancers are linked to these genetic syndromes.)

What are the symptoms of colorectal cancer?

Colorectal cancer first develops with few, if any, symptoms. However, if symptoms are present, they may include:

• Blood in or on the stool;
• A change in bowel habits;
• Stools that are narrower than usual;
• General, unexplained stomach discomfort;
• Frequent gas, pains or indigestion;
• Unexplained weight loss; and
• Chronic fatigue.

These symptoms can also be associated with many other health conditions. If you have any of these symptoms, discuss them with your doctor. Only your doctor can determine why you're having these symptoms.

Who is at risk of developing colorectal cancer?

Colorectal cancer occurs in men and women of all racial and ethnic groups. Approximately 75% of colorectal cancers occur in people with no known risk factors. Other important facts about risk for colorectal cancer include:

• More than 90% of colorectal cancers are diagnosed in people aged 50 or older. The risk of developing colorectal cancer increases with age.
• A family history of colorectal cancer or colorectal polyps may increase a person's risk of developing colorectal cancer.
• Certain diseases of the intestines, including inflammatory bowel disease (ulcerative colitis or Crohn's disease), can increase the risk for colorectal cancer.

Is there anything I can do to reduce my risk for colorectal cancer?

There is strong scientific evidence that having regular screening tests for colorectal cancer beginning at age 50 reduces deaths from colorectal cancer. Screening tests can find precancerous polyps (abnormal growths) in the colon and rectum, and polyps can be removed before they turn into cancer.

Studies have also shown that increased physical activity and maintaining a healthy weight can decrease the risk for colorectal cancer. Evidence is less clear about other ways to prevent colorectal cancer.

Research is underway to determine whether dietary changes may decrease the risk for colorectal cancer. Currently, there is no consensus on the role of diet in preventing colorectal cancer; however, medical experts recommend a diet low in animal fats and high in fruits, vegetables, and whole grain products to reduce the risk of other chronic diseases, such as coronary artery disease and diabetes. This diet also may reduce the risk of colorectal cancer.

In addition, researchers are examining the role of certain medications and supplements, including aspirin, calcium, vitamin D, and selenium, in preventing colorectal cancer. Overall, the most effective way to reduce your risk of colorectal cancer is by having regular colorectal cancer screening tests beginning at age 50.

What is colorectal cancer screening?

Screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, are effective when they can detect disease early. Detecting disease early can lead to more effective treatment. In some cases, screening tests can detect abnormalities such as polyps before they have a chance to turn into cancer. So removing polyps can prevent colorectal cancer from developing.

What are the screening tests for colorectal cancer?

Several tests are available to screen for colorectal cancer. Some are used alone; others are used in combination with each other. Talk with your doctor about which test or tests are best for you.

Fecal Occult Blood Test (FOBT)- This test checks for occult (hidden) blood in the stool. At home, you place a small amount of your stool from three consecutive bowel movements on test cards. You return the cards to your doctor's office or a lab where they're checked for blood. This test is recommended yearly. (If blood is found, you will need a follow-up colonoscopy.)

Flexible Sigmoidoscopy- Before this test, you use a strong laxative and/or enema to clean out the colon. Flexible sigmoidoscopy is conducted in a doctor's office, clinic, or hospital. The doctor (or other specially-trained healthcare professional) uses a narrow, flexible, lighted tube to look at the inside of the rectum and the lower portion of the colon. During the exam, the doctor may remove polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every five years. (If polyps are found, you will need a follow-up colonoscopy.)

Combination of FOBT and Flexible Sigmoidoscopy- Some doctors recommend having both FOBT and flexible sigmoidoscopy to increase the chance of finding polyps and cancers. When used in combination, FOBT is recommended yearly and flexible sigmoidoscopy is recommended every five years.

Colonoscopy- Before this test, you take a strong laxative to clean out the colon. Colonoscopy is conducted in a doctor's office, clinic, or hospital. You are given a sedative to make you more comfortable while the doctor uses a narrow, flexible, lighted tube to look at the inside of the rectum and the entire colon. This test is similar to flexible sigmoidoscopy, except the tube used is longer and allows the doctor to see the entire colon. During the exam, the doctor may remove polyps and collect samples of tissue or cells for closer examination. This test is recommended every 10 years. (Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests.)

Double-Contrast Barium Enema- This test is conducted in a radiology center or hospital. Before the test, you use a strong laxative and/or enema to clean out the colon. For this procedure, you are given an enema with a barium solution, followed by an injection of air. An X-ray of the rectum and colon is then taken. The barium coats the lining of the intestines so that polyps and other abnormalities are visible on the X-ray. This test is recommended every five years. (If polyps are found, you will need a follow-up colonoscopy.)

Who should be tested for colorectal cancer?

All men and women aged 50 years and older should be tested for colorectal cancer routinely. Others who are at increased risk should speak to their doctors about earlier or more frequent testing. Those at increased risk are people with:
A family history of colorectal cancer or colorectal polyps;
Certain diseases of the intestines, including inflammatory bowel disease (ulcerative colitis or Crohn's disease); or
Genetic syndromes such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC). (Just 5% of colorectal cancers are linked to these genetic syndromes).

What about testing for colorectal cancer using newer technology, such as virtual colonoscopy, fecal immunochemical testing (FIT or iFOBT), and stool DNA testing?

Although virtual colonoscopy and stool DNA testing are used in some medical settings, data are not yet sufficient to support these tests for colorectal cancer screening. Research is underway to evaluate their effectiveness as screening tests, especially compared with the screening tests already recommended for colorectal cancer.

Virtual colonoscopy, also called computed tomographic (CT) colonography, uses multiple CT images to create a three-dimensional view of the colon. As is the case with traditional colonoscopy, a patient must prepare for virtual colonoscopy by drinking a strong laxative to clean out the colon thoroughly.

During virtual colonoscopy, air is pumped into the rectum to expand the rectum and colon. If a polyp or other abnormality is found, it cannot be removed during this procedure. A follow-up colonoscopy will be necessary to remove polyps or take tissue samples for further analysis. Because virtual colonoscopy is still considered experimental, most insurance plans do not cover the procedure.

The fecal immunochemical test (FIT or iFOBT) is a newer kind of stool blood test kit. It detects occult (hidden) blood in the stool. This test is done essentially the same way as FOBT, but is more specific and has fewer false positive results. Vitamins and foods do not affect this test, so dietary restrictions are not necessary. As with FOBT, the FIT may not detect a tumor that is not bleeding, and you will need to have a colonoscopy if the test results show there is hidden blood in the stool. Organizations that issue screening guidelines are studying when and if to add FIT to the recommendations.

Molecular testing of genetic material (DNA) in stool is another promising technology that may become an option for screening in the future. This technique has not yet been shown to detect precancerous polyps and is still experimental.

Why should I get screened for colorectal cancer?

Screening saves lives. Colorectal cancers almost always develop from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find polyps, so they can be removed before they turn into cancer. Screening tests also can find colorectal cancer early, when treatment works best and the chance for a full recovery is very high.

Having regular screening tests beginning at age 50 could save your life.

How do I know which screening test is right for me?

Scientific data do not currently suggest that there is a single "best test" for any one person. Each test has advantages and disadvantages. Patients and their doctors are encouraged to discuss the benefits and potential risks associated with each screening option as they decide which test to use and how often the patient should be tested. Which test to use will depend on:
A patient's preferences;
A patient's medical condition;
The likelihood that the patient will have the test; and
The resources available for testing and follow-up.

Is colorectal cancer screening covered by insurance?

Most insurance plans help pay for screening tests for people aged 50 or older. Many plans also help pay for screening tests for people less than age 50 who are at increased risk for colorectal cancer. Check with your health insurance provider to determine your colorectal cancer screening benefits.