Col­orec­tal Cancer

Colorectal cancer is a disease in which cells in the colon or rectum grow out of control. Sometimes it is called colon cancer, for short. The colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus.

Sometimes abnormal growths, called polyps, form in the colon or rectum. Over time, some polyps may turn into cancer. Screening tests can find polyps so they can be removed before turning into cancer. Screening also helps find colorectal cancer at an early stage, when treatment works best.

Your risk of getting colorectal cancer increases as you get older. Other risk factors include having—

• Inflammatory bowel disease such as Crohn’s disease or ulcerative colitis.
• A personal or family history of colorectal cancer or colorectal polyps.
• A genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).

Lifestyle factors that may contribute to an increased risk of colorectal cancer include—

• Lack of regular physical activity.
• A diet low in fruit and vegetables.
• A low-fiber and high-fat diet, or a diet high in processed meats.
• Overweight and obesity.
• Alcohol consumption.
• Tobacco use.

Overall, the most effective way to reduce your risk of colorectal cancer is to get screened for colorectal cancer routinely, beginning at age 45.

Almost all colorectal cancers begin as precancerous polyps (abnormal growths) in the colon or rectum. Such polyps can be present in the colon for years before invasive cancer develops. They may not cause any symptoms, especially early on. Colorectal cancer screening can find precancerous polyps so they can be removed before they turn into cancer. In this way, colorectal cancer is prevented. Screening can also find colorectal cancer early, when treatment works best.

“I’ve been screened twice. I made everybody I love get screened,” says actress Meryl Streep in this video. “People that are screened early and find cancer and are treated early—they’re alive because of that early detection.”

Diet

Research is underway to find out if changes to your diet can reduce your colorectal cancer risk. Medical experts often recommend a diet low in animal fats and high in fruits, vegetables, and whole grains 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.

Aspirin

Researchers are looking at the role of some medicines and supplements in preventing colorectal cancer. The U.S. Preventive Services Task Force found that taking low-dose aspirin can help prevent cardiovascular disease and colorectal cancer in some adults, depending on age and risk factors. For more information, download Aspirin Use to Prevent Cardiovascular Disease and Colorectal Cancer: Preventive Medication.

Healthy Choices

Some studies suggest that people may reduce their risk of developing colorectal cancer by increasing physical activity, keeping a healthy weight, limiting alcohol consumption, and avoiding tobacco.

Colorectal polyps (abnormal growths in the colon or rectum that can turn into cancer if not removed) and colorectal cancer don’t always cause symptoms, especially at first. Someone could have polyps or colorectal cancer and not know it. That is why getting screened regularly for colorectal cancer is so important.

If you have symptoms, they may include—

• A change in bowel habits.
• Blood in or on your stool (bowel movement).
• Diarrhea, constipation, or feeling that the bowel does not empty all the way.
• Abdominal pain, aches, or cramps that don’t go away.
• Weight loss and you don’t know why.

If you have any of these symptoms, talk to your doctor. They may be caused by something other than cancer. The only way to know what is causing them is to see your doctor.

What Is Colorectal Cancer Screening?

A screening test is used to look for a disease when a person doesn’t have symptoms. (When a person has symptoms, diagnostic tests are used to find out the cause of the symptoms.)

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.

Screening Recommendations

Regular screening, beginning at age 45, is the key to preventing colorectal cancer and finding it early. The U.S. Preventive Services Task Force (Task Force) recommends that adults age 45 to 75 be screened for colorectal cancer. The Task Force recommends that adults age 76 to 85 talk to their doctor about screening.

The Task Force recommends several colorectal cancer screening strategies, including stool tests, flexible sigmoidoscopy, colonoscopy, and CT colonography (virtual colonoscopy). Learn about these screening tests.

When Should I Begin to Get Screened?

Most people should begin screening for colorectal cancer soon after turning 45, then continue getting screened at regular intervals. However, you may need to be tested earlier than 45, or more often than other people, if you have—

• Inflammatory bowel disease such as Crohn’s disease or ulcerative colitis.
• A personal or family history of colorectal cancer or colorectal polyps.
• A genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).

If you think you are at increased risk for colorectal cancer, speak with your doctor about—

• When to begin screening.
• Which test is right for you.
• How often to get tested.

Insurance and Medicare Coverage

Colorectal cancer screening tests may be covered by your health insurance policy without a deductible or co-pay. For more information about Medicare coverage, visit www.medicare.gov or call 1-800-MEDICARE (1-800-633-4227). TTY users should call 1 (877) 486-2048. Check with your insurance plan to find out what benefits are covered for colorectal cancer screening.

The U.S. Preventive Services Task Force (Task Force) recommends that adults age 45 to 75 be screened for colorectal cancer. The decision to be screened between ages 76 and 85 should be made on an individual basis. If you are older than 75, talk to your doctor about screening. People at an increased risk of getting colorectal cancer should talk to their doctor about when to begin screening, which test is right for them, and how often to get tested.

Several screening tests can be used to find polyps or colorectal cancer. The Task Force outlines the following colorectal cancer screening strategies. It is important to know that if your test result is positive or abnormal on some screening tests (stool tests, flexible sigmoidoscopy, and CT colonography), a colonoscopy test is needed to complete the screening process. Talk to your doctor about which test is right for you.

Stool Tests

• The guaiac-based fecal occult blood test (gFOBT) uses the chemical guaiac to detect blood in the stool. It is done once a year. For this test, you receive a test kit from your health care provider. At home, you use a stick or brush to obtain a small amount of stool. You return the test kit to the doctor or a lab, where the stool samples are checked for the presence of blood.
• The fecal immunochemical test (FIT) uses antibodies to detect blood in the stool. It is also done once a year in the same way as a gFOBT.
• The FIT-DNA test (also referred to as the stool DNA test) combines the FIT with a test that detects altered DNA in the stool. For this test, you collect an entire bowel movement and send it to a lab, where it is checked for altered DNA and for the presence of blood. It is done once every three years.

Flexible Sigmoidoscopy

For this test, the doctor puts a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon.

How often: Every 5 years, or every 10 years with a FIT every year.

Colonoscopy

This is similar to flexible sigmoidoscopy, except the doctor uses a longer, thin, flexible, lighted tube to check for polyps or cancer inside the rectum and the entire colon. During the test, the doctor can find and remove most polyps and some cancers. Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests.

How often: Every 10 years (for people who do not have an increased risk of colorectal cancer).

CT Colonography (Virtual Colonoscopy)

Computed tomography (CT) colonography, also called a virtual colonoscopy, uses X-rays and computers to produce images of the entire colon, which are displayed on a computer screen for the doctor to analyze.

How often: Every 5 years.

How Do I Know Which Screening Test Is Right for Me?

Each test has advantages and disadvantages. Talk to your doctor about the pros and cons of each test, and how often to be tested. Which test to use depends on—

• Your preferences.
• Your medical condition.
• Your personal or family history of colorectal cancer or colorectal polyps.
• If you have a genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).
• The likelihood that you will get the test.
• The resources available for testing and follow-up.

Know Before You Go

The U.S. Preventive Services Task Force recommends that adults age 45 to 75 get screened for colorectal cancer. The decision to get screened between ages 76 and 85 should be made on an individual basis. If you are older than 75, talk to your doctor about screening. People at an increased risk of developing colorectal cancer should talk to their doctors about when to begin screening, which test is right for them, and how often to get tested.

Several screening tests can be used to find polyps or colorectal cancer. The benefits and risks of these screening methods vary. Discuss with your doctor which test is best for you, and check with your insurance provider to find out which tests are covered by your insurance plan, and how much you will have to pay. Medicare helps pay for colorectal cancer screening.

Ask Your Doctor

Do I need to get a screening test for colorectal cancer?

• What screening test(s) do you recommend for me? Why?
• How do I prepare? Do I need to change my diet or my usual medication before taking the test?
• What’s involved in the test? Will it be uncomfortable or painful?
• Is there any risk involved?
• When and from whom will I get results?

If you’re having a colonoscopy or sigmoidoscopy, you will want to know—

• Who will do the exam?
• Will I need someone with me?

If You’re at Increased Risk

Some people are at increased risk because they have inflammatory bowel disease, a personal or family history of colorectal polyps or colorectal cancer, or genetic syndromes like familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (also known as Lynch syndrome). These people may need to start screening earlier than age 45. If you believe you are at increased risk, ask your doctor if you should begin screening earlier than age 45.

If You’re Having Symptoms

Tell your doctor if you have any of these symptoms—

• A change in bowel habits.
• Blood in or on your stool (bowel movement).
• Diarrhea, constipation, or feeling that the bowel does not empty all the way.
• Abdominal pain, aches, or cramps that do not go away.
• Weight loss and you don’t know why.

These symptoms may be caused by something other than cancer, but the only way to know what is causing them is to speak with your doctor about them.