are you at risk for colon cancer?

1. What is the chance that I might get colon cancer?

• About 1 in 17 (5-6%) men will get colon cancer at some point in their lives.[3]
• About 1 in 18 (5-6 %) women will get colon cancer at some point in their lives.[3]
• In most cases, colon cancer occurs sporadically (by chance).[3]
• About 25% of colon cancer runs in families.[3] There are two types of colon cancer that run in a family - familial and hereditary. The type is mainly decided by the number of people in a family with cancer and/or the age when they were diagnosed. Together, these two types of cancer add up to about 25% of all colon cancer cases. See pie chart below.

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2. What are some signs of colon cancer?

Some of the symptoms of colon cancer:

• Pain or tenderness of the abdomen
• A change in your bowel habits
• Rectal bleeding
• Blockage in the bowel
• A mass in the abdomen or rectum
• Anemia
• Weight loss

Having one or more of these symptoms does not mean you have colon cancer.[4] If you have any of these symptoms, talk to your doctor. Your doctor may be able to tell you why you are having these symptoms.

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3. Are there different causes of colon cancer?

Hover over each area of the graph below to learn about the different causes of colon cancer.

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4. How do I know if I am at higher risk for a Hereditary Colon Cancer Syndrome?

You may be at higher risk for a hereditary colon cancer syndrome if you have: [8, 9]

• Multiple relatives with colorectal cancer
• Relatives with colon cancer in each generation
• One or more relatives with colon cancer before the age of 50
• Relatives with other cancers found in hereditary colon cancer syndromes, such as endometrial, stomach, ovarian, intestinal, urinary tract, gallbladder, brain, skin, or thyroid cancer.
• Two or more primary cancers, or more than 10 adenomas in the same person

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5. How do I know if I am at higher risk for Familial Colon Cancer?

You may be at higher risk for familial colon cancer if you have: [8, 9]

• One first-degree relative with colon cancer or adenomatous polyps diagnosed after the age of 50.

OR

• Two first-degree relatives diagnosed with colorectal cancer at any age

OR

• Two second-degree relatives with colorectal cancer at any age

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6. What is the difference between colon polyps and colon cancer?

• Polyps are NOT cancer.
• There are different types of polyps. About 2/3 of colon polyps are adenomas, or polyps that can develop into cancer over time.[6]
• Most colon cancers develop from adenomatous colon polyps.[3]
• About 1 in 4 (25%) people will have an adenomatous colon polyp by the age of 50. The chance of getting these polyps increases with age.[4]
• The National Comprehensive Cancer Network recommends colonoscopy to screen for colon polyps. If polyps are found on colonoscopy, they are removed to help prevent cancer from developing.[8]

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7. Are there things that can increase my chance for getting colon cancer?

There are risk factors that can increase your risk for getting polyps in your colon and colon cancer. Some risk factors are out of your control. These include:

• Your Race/Ancestry: African Americans have a higher chance of getting colon cancer than Caucasian people.[3] People of Ashkenazi Jewish ancestry are more likely to get colon cancer. The lifetime risk of colon cancer in this population is 9-15%.[10]
• Increasing Age: The chance of getting adenomatous colon polyps and colon cancer increases with age. Nine out of 10 colon cancers occur after the age of 50.[3]
• Personal History of Chronic Inflammatory Bowel Disease (IBD): People who have a disease in which the colon is inflamed over a long period of time (such as ulcerative colitis and Crohn's disease) have a higher chance of getting colon cancer.[11] The National Comprehensive Cancer Network recommends screening for colon cancer after 8-10 years of IBD symptoms.[8]
• Personal History of Adenomatous Colon Polyps: People who have had an adenomatous polyp have a higher chance of getting colon cancer. The risk is even greater if the polyp was large or if there was more than one polyp.[3]
• Personal History of Colon Cancer: People who have had colon cancer are more likely to get cancer in new areas of the colon and rectum. This is true even if the first cancer has been completely removed.[3]
• Family Health History: A family history of adenomatous polyps, colon cancer, or other cancers found in hereditary colon cancer syndromes increases your risk for getting colon cancer. Having a first degree relative diagnosed with colon cancer before the age of 45 or having more than one first degree relative with colon cancer increases your risk of getting colon cancer to about 4 times that of the average person.[1,7]
• Your Genes: About 25% of colon cancer runs in families.[1] About 5-6% of colon cancer is caused by a change in a gene.[6]

Some other risk factors that may be in your control include:

• Drinking Alcohol: People who drink 4 or more alcoholic drinks a week have a higher chance of getting colon cancer.[3] The more drinks per week, the higher the chance of colon cancer.[7]
• Smoking Cigarettes: Long-term tobacco smoking (at least 35 years) increases the risk for adenomatous colon polyps and colon cancer.[3,7]
• Being Overweight: Being overweight increases the risk for adenomatous polyps to form and progress into colon cancer. Men who are overweight have a higher risk than women who are overweight.[7]
• Diet: People who eat 7 or more servings of red meat a week have a higher chance of getting colon cancer.[7]

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8. How can I lower my chance for getting colon cancer?

• Limit the number of alcoholic drinks to less than 4 a week.
• Refrain from smoking cigarettes.
• Maintain a healthy weight for your age and height.
• Exercise: The American Cancer Society recommends that people be active for 30-45 minutes, 5 days a week to reduce the risk of colon cancer.

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9. What should I do if I think I have a higher chance of getting colon cancer?

• Collect your family health history. This is the first step to assess your risk of colon cancer.
• Share your family health history with your doctor. Your history may help your doctor decide if you need to be screened more often or at an earlier age for colon cancer. If your risk is high, your doctor may refer you to a genetic specialist or genetic counselor.
• Talk with your doctor about ways to lower your risk. If your doctor thinks you have a higher chance of getting colon cancer as a result of your family health history, he or she may suggest:[3]
• Earlier or more frequent screening, including colonoscopy, fecal occult blood test, sigmoidoscopy, and double contrast barium enema.
• Joining research projects aimed at preventing colon cancer
• Taking medications or dietary supplements thought to reduce the risk of colon cancer such as:
• Aspirin
• Postmenopausal hormones (although may increase risk for breast cancer and cardiovascular disease
• Multivitamins with folic acid
• Calcium supplements
• Genetic testing is only useful in a small number of cases.
• Talk to your family about your risk. If you are at risk for colon cancer, your family members may be too. Talk to them about the information you find.

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10. Is there a test that can tell me if I have a higher chance of getting colon cancer?

Genetic testing is NOT for everyone!

• Only a small number of people have a change in a gene that greatly increases their chance of getting colon and other cancers.
• Your doctor may refer you to a genetic specialist to find out if genetic testing is right for you.

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11. Is there a tool on the internet that can estimate my chance of getting colon cancer?

The Washington University School of Medicine has a risk assessment tool for colon cancer:[12]

• www.yourdiseaserisk.wustl.edu
• This tool is most accurate for people over the age of 40 who have never had any type of cancer. Even so, anyone can use it.
• You can also use this tool to assess your risk of getting other types of cancer, diabetes, heart disease, osteoporosis, and stroke.

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12. What other internet resources are available?

1. American Cancer Society: www.cancer.org

   This website has information about many types of cancer including colon and rectal cancer.  Information guides include both an overview and more detailed information about the causes, risk factors, prevention, and treatment of colorectal cancer.  You can also read about personal cancer experiences.  This section has suggestions about how to cope with having colorectal cancer.  The site can also be viewed in Spanish.

2. American Gastroenterological Association: www.gastro.org/patient-center

   The Patient Center contains facts about colorectal cancer, symptoms, risk factors, and ways to prevent colorectal cancer.  You will also find information about screening tests and patient brochures in Spanish.

3. Colon Cancer Alliance: www.ccalliance.org

   The Colon Cancer Alliance (CCA) is made up of colon and rectal cancer survivors, their families, caregivers, and the medical community.  This site has information about colorectal cancer, symptoms, screening, personal stories, and links to information about genetic factors that may increase the risk of colorectal cancer.  There is also information about financial issues, quality of life issues, book and video reviews, a toll-free helpline, a buddy program, and an online chat community.

4. Colorectal Cancer Coalition: www.fightcolorectalcancer.org

   Information on this site is mainly for healthcare professionals and people with colorectal cancer.  Topics for patients include prevention, screening, diagnosis, treatment, dealing with side effects, clinical trials, support and medical resources.  You can also sign up for the free mailed (print) newsletter.

5. National Cancer Institute: www.cancer.gov/cancertopics/types/colon-and-rectal

   This site has definitions of colon and rectal cancer, information about prevention, screening and testing, genetics, the causes of colon cancer, treatment, research, and statistics.  You can also download an online booklet, “What You Need to Know About Cancer of the Colon and Rectum” to help you learn about colon and rectal cancer symptoms, diagnosis, treatment, and what to ask your doctor.

References

1. National Cancer Institute. Genetics of Colorectal Cancer (PDQ) Health  Professional Version. Available at: http://www.cancer.gov/cancertopics/pdq/genetics/colorectal/HealthProfessional/allpages/.  Accessed February 16, 2007.
2. Strate LL & Syngal S. (2005). Hereditary colorectal cancer syndromes. Cancer Causes and Control 16(3):201-213.
3. American Cancer Society. Colorectal Cancer Facts & Figures Special Edition 2005. Atlanta: American Cancer Society, 2005. Available at: www.cancer.org/downloads/COM/CRCF&F2005final.pdf  Accessed February 16, 2007.
4. Winawer SJ, Fletcher RH, Miller L, et al. (1997). Colorectal cancer screening: Clinical guidelines and rationale. Gastroenterology 112(2):594-642.
5. Wikipedia, The Free Encyclopedia.  Available at:  http://en.wikipedia.org/wiki/Main_Page  Accessed January 26, 2007.  
6. Winawer SJ. (1999). Natural history of colorectal cancer. Am J Med 106(1)Supp1:3-6.
7. Tomeo CA, Colditz GA, Willett WC, et al. (1999). Harvard Report on Cancer Prevention.  Volume 3: prevention of colon cancer in the United States.  Cancer Causes Control 10(3):167-180.
8. National Comprehensive Cancer Network: Guidelines for detection, prevention, & risk reduction of cancer.  Available at:  http://www.nccn.org/professionals/physician_gls/f_guidelines.asp?button=I+Agree#detection.  Accessed February 16, 2007.
9. Winawer S, Flectcher R, Rex D, et al. (2003). Colorectal cancer screening and surveillance: Clinical guidelines and rationale - update based on new evidence. Gastroenterology 124(2):544-560.

10. Lynch HT, Rubinstein WS, & Locker GY. (2004). Cancer in Jews: Introduction and overview. Familial Cancer 3(3-4):177-192. 
11. Greenstein AJ. (2000). Cancer in inflammatory bowel disease. Mt Sinai J Med 67(3):227-240.
12. The Harvard Center for Cancer Prevention Disease Risk Assessment Tool: www.yourdiseaserisk.harvard.edu/.  Accessed February 16, 2007.  

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