Which test should I have to screen for colorectal cancer?

Introduction

Screening tests detect specific diseases before symptoms appear. Several tests can screen for colorectal cancer. Each test has its pros and cons. This information will help you understand your choices, whether you share in the decision-making process or rely on your doctor's recommendation.

Key points in making your decision

• Regular screening can greatly decrease your risk of dying from colorectal cancer.
• Regular screening is recommended for everyone age 50 and older.
• Screening tests look for colon polyps. Most cases of colorectal cancer begin as polyps. When polyps are found, they can be removed before they become cancer or while the cancer is in its early stages.
• Colorectal cancer rarely causes symptoms in the beginning. Symptoms such as bleeding from the rectum, a change in bowel habits, and weight loss usually occur later, when the cancer is harder to treat.
• You may need to begin screening at age 40 or earlier and be tested more often if you or members of your family have a history of colon polyps or colorectal cancer.
• You may need to begin screening earlier if you have Crohn's disease or ulcerative colitis.

Medical Information

What is colorectal cancer?

Colorectal cancer is the out-of-control growth of cells in the colon or rectum. These cells grow into masses, or tumors. Most colorectal cancers begin as polyps, which are growths attached to the inside of the colon or rectum. Colon polyps are common, but most of them do not turn into cancer. Some polyps are found with screening tests. With colonoscopy and sigmoidoscopy, polyps can be removed during the same procedures.

Colorectal cancer is the third most common cancer in men and women in the United States, and is the second leading cause of cancer deaths.¹ It most often strikes people who are older than 50 who have no risk factors in their backgrounds other than their age.

For more information, see the topic Colorectal Cancer.

What are the symptoms of colorectal cancer?

Early-stage colorectal cancer rarely causes symptoms. Symptoms of colorectal cancer usually occur later, when the cancer is are harder to treat. Common symptoms include:

• Pain in the abdomen.
• Blood in your stool or black, tarry stools.
• A change in your bowel habits (such as very narrow stools or frequent diarrhea or constipation).
• Unexplained weight loss.
• Constant fatigue.

Why is regular screening important?

Most colorectal cancer cases can be prevented by having regular screening tests and having polyps removed. Survival rates are higher when colorectal cancer is found and treated early before it spreads to lymph nodes or other organs.

Why is my family's history important?

You are twice as likely to get colorectal cancer if one of your parents, brothers, sisters, or children has had it, especially if that person was diagnosed before the age of 50. The two most common inherited causes of colorectal cancer are familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC). Most people with these conditions will develop colorectal cancer if they are not treated.

If you have any of these conditions in your background, you will need to be screened at an earlier age-and have more frequent screening-than other people.

For more information, see the topic Colorectal Cancer.

Your Information

Several tests are available to screen for colorectal cancer:

• Stool tests. These include:
  • A fecal occult blood test (FOBT), every year.
  • A fecal immunochemical test (FIT), every year.
  • A stool DNA test (sDNA). Experts have not yet set guidelines for how often this test should be done.²
• Barium enema, usually done every 5 years.
• Flexible sigmoidoscopy, usually done every 5 years.
• A stool test each year and a flexible sigmoidoscopy every 5 years.
• Colonoscopy, usually done every 10 years.
• Computed tomographic colonography (CTC), also known as virtual colonoscopy, possibly done every 5 years. Experts have not yet set guidelines for how often this test should be done.²

Flexible sigmoidoscopy (also called a sigmoidoscopy or shortened to "flex sig") and colonoscopy are done in doctor's offices, clinics, and hospitals. A barium enema is done in a hospital or outpatient radiology department.

Complications from barium enema, colonoscopy, or sigmoidoscopy include damage to or puncture of the colon. These complications are rare, but are somewhat more common with colonoscopy than with virtual colonoscopy, barium enema, or sigmoidoscopy. Colonoscopy and barium enemas are not recommended for pregnant women, although a colonoscopy can be done if needed.

The decision about choosing a test for colorectal cancer screening takes into account your personal feelings and the medical facts.

Pros and cons of colorectal cancer screening tests

These personal stories may help you make your decision.

Wise Health Decision

Use this worksheet to help you make your decision. After completing it, you should have a better idea of how you feel about having a screening test for colorectal cancer. Discuss the worksheet with your doctor.

Circle the answer that best applies to you.

Use the following space to list any other important concerns you have about this decision.

What is your overall impression?

Your answers in the above worksheet are meant to give you a general idea of where you stand on this decision. You may have one overriding reason for making your choice.

Return to the topic:

• Colonoscopy
• Colon Polyps
• Colorectal Cancer
• Fecal Occult Blood Test (FOBT)
• Sigmoidoscopy

References

Citations

1. American Cancer Society (2005). Colorectal Cancer Facts and Figures: Special Edition 2005, pp. 1-20. Available online: http://www.cancer.org/docroot/STT/content/STT_1x_Colorectal_Cancer_Facts_and_Figures_-_Special_Edition_2005.asp.

2. Levin B, et al. (2008). Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: A joint guideline from the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA: A Cancer Journal for Clinicians, 58(3): 130-160.