Genetic Risk of Colon Cancer
March 27, 2013
As March is Colon Cancer Awareness Month, Cleveland Clinic is committed to educating the public on prevention, diagnosis and treatment of this disease. Some important risk factors include age; African-American race; personal and family history of colon cancer and polyps, ulcerative colitis or Crohn disease; smoking and being overweight or obese.
Did you know colon cancer is one of the most common cancers? If detected early, it's also one of the most curable. A family history and the genetic components of colon cancer are two risk factors that cannot be altered, but keep in mind that the presence of abnormal genes does not mean that a person or his or her children will develop the disease. It does mean that a person has a higher than average risk for the disease. Hereditary cancer syndromes account for approximately 5 to 10 percent of colon cancer cases. However, external factors, such as environment exposures and diet, might play a role in whether disease develops.
About the Speakers
Charis Eng, MD, PhD, is the Sondra J. and Stephen R. Hardis endowed Chairwoman and founding director of the Genomic Medicine Institute at Cleveland Clinic and American Cancer Society Professorship of Clinical Cancer Research. Dr. Eng is the founding director and attending clinical cancer geneticist of the Genomic Medicine Institute's clinical component, the Center for Personalized Genetic Healthcare. She is also Professor and Vice Chairman of the Department of Genetics and Genome Science at Case Western Reserve University School of Medicine.
She holds a joint appointment as Professor of Molecular Medicine at the Cleveland Clinic Lerner College of Medicine and is a full member of Cleveland Clinic's Taussig Cancer Center and of the CASE Comprehensive Cancer Center. She continues to hold an honorary appointment at the University of Cambridge.
After completing medical school and a doctorate at University of Chicago Pritzker School of Medicine, Dr. Eng completed her residency in internal medicine at Beth Israel Deaconess Medical Center and Harvard Medical School, in Boston, and completed a fellowship in medical oncology at both Harvard's Dana-Farber Cancer Institute and Brigham & Women’s Hospital, in Boston.
She was formally trained in clinical cancer genetics and laboratory-based human cancer genetics at the University of Cambridge School of Medicine and the Royal Marsden NHS Trust, in Cambridge, United Kingdom.
Matthew Kalady, MD, is a staff surgeon and an assistant professor of surgery in the Department of Colorectal Surgery in Cleveland Clinic’s Digestive Disease Institute.
Dr. Kalady holds the Krause-Lieberman Chair in Colorectal Surgery and is certified by the American Board of Colorectal Surgery and the American Board of Surgery. He is the Director of the Colorectal Cancer Translational Science Laboratory and has joint appointments in the Cancer Biology Department (Lerner Research Institute) and the Taussig Cancer Center at Cleveland Clinic. Dr. Kalady has a clinical and scientific interest in the causes and treatment of colorectal cancer, including hereditary colorectal cancer syndromes. He is the Vice-Chairman of the Sanford D. Weiss, MD, Center for Hereditary Colorectal Neoplasia and head of the Hereditary Nonpolyposis Colorectal Cancer Section of the Jagelmen Registries.
After graduating from medical school, Dr. Kalady completed his internship and residency in surgery at Duke University School of Medicine, in Durham, NC. He completed his fellowship in colorectal surgery at Cleveland Clinic.
Let’s Chat About Genetic Risk of Colon Cancer
Moderator: Welcome to our Online Health Chat with Cleveland Clinic experts Dr. Charis Eng and Dr. Matthew Kalady. We are thrilled to have them here today for this chat. Let’s begin with some of your questions.
Risk of Colon Cancer
judop: Who is considered at high risk for colon cancer?
Charis_Eng,_MD,_PhD: There are many reasons for having a higher risk for colon cancer. If someone has inflammatory bowel disease (e.g., Crohn disease), especially if there is active disease, then that person is at an increased risk of colon cancer. There is also a genetic risk for colon cancer. Taking a family history is one way to determine whether someone is at an increased risk of colon cancer.
Colon Cancer Prevention and Screening
gunther: At what age do you recommend testing?
Charis_Eng,_MD,_PhD: It depends on what your risk is. If you are not sure, then ask your primary care physician. If you are at all concerned you are at genetic risk of cancer, then ask for a referral for a genetics evaluation.
cs1442: I have two friends that are in stage 4 colon cancer that has spread to their livers. Both friends are very young and are only in their late 30s (38 and 39 years old). Is this a new trend to see these types of aggressive cancers at an earlier younger age? Is there any routine prescreening that can be done to detect cancer? Are there dietary suggestions to help prevent cancer?
Matthew_Kalady,_MD: The average age for colon cancer diagnosis is 70 years old. It is highly unusual for someone to develop cancer in their 30s. Often these people develop cancer within a hereditary syndrome and a family history would be important in detecting cancer at earlier ages. There are also cancers in young patients that are not associated with hereditary syndromes, and we do not know the reasons why these develop. There is a general trend for cancers developing in younger patients in the United States. Again, the reasons for this are unknown. I am not aware that colon cancer in younger patients tends to be more aggressive. However, it is likely that the cancer are not detected until later stages because symptoms are often not noticed or attributed to something more benign because cancer is so unusual at this age.
Screening to detect cancer is based on your family history. Without a family history and without cancer symptoms the age is typically 50 years old. If you have a first-degree relative with cancer at a young age, the recommendation is to undergo screening 10 years before that age at which it was found in the relative.
gmills: What are the general guidelines for testing for colon cancer? At what age do you start and how often?
Charis_Eng,_MD,_PhD: The American Cancer Society guidelines for colon cancer screening for the general population (i.e., without increased risk of colon cancer) is beginning colonoscopies at the age of 50 years old, and then every 10 years thereafter.
Familial Colon Cancer: Diagnosis and Screening
taiterchip: My mother and her father both had colon cancer. What are the odds that I will also get it? My mother passed away from cancer (it spread from the colon in 2006 at the age of 68 years old). I am now 54 years old.
Charis_Eng,_MD,_PhD: If both your father and mother had colon cancer in their 60s , we can estimate that your mother’s colon cancer started around age 58 (10 years younger than when it spread). You would be only at a slightly increased risk of colon cancer than another individual with no colon cancers or risk factors in his or her family. This is because the age range from the 50s to 60 is the average age that individuals in the general population get colon cancer. You should have already started your routine colonoscopies since you are 54 years old.
The good news is that colonoscopies catch precancers (polyps) and nip them out, thus preventing colon cancer from forming. If you wish to have your family-related colon cancer risk assessed, then you should get a genetics consultation.
MrsSanta: Is there is an available test that would tell whether you are likely to develop colon cancer other than colonoscopy screening. I know it runs in families. My mother was diagnosed with stage 4 this past July. She had her colonoscopy within the past 10 years. However, it was so low that her oncologists said that it's possible that it was missed during the colonoscopy. As far as I know, there are no other family members that have had the disease. I have had kidney cancer and my father had prostate cancer.
Charis_Eng,_MD,_PhD: A professional genetics evaluation will also ensure that the correct gene is tested for. There are many genes which predispose someone to colon cancer. Therefore, depending on which particular gene is altered, other types of cancers may be involved as well. Most genetic tests involve a blood draw. Genetic testing usually takes two to eight weeks to complete (compared to 10 years ago, which took one year to complete). Once the result comes back, the genetics professional will interpret the results and provide advice on how your doctors can use the gene test results to personalize your treatment.
there4jsweetie: My mother died at 70 years old from colon cancer. She also had Crohn disease and had a portion of her colon removed when she was 61 years old. My father died at 86 years old from prostate cancer that had metastasized in the colon. I am a 65-year-old male with irritable bowel syndrome, diverticulosis and hemorrhoids. I am currently on a schedule with my doctor to have a colonoscopy every five years, which bothers me. I feel that I should have them more often. For your patients, how often would you recommend a colonoscopy?
Matthew_Kalady,_MD: The interval between screening colonoscopies depends on personal history of polyps and/or colorectal cancer and the findings of the most current examination. Irritable bowel syndrome, diverticulitis and hemorrhoids do not put you at an increased risk of colon cancer. Given your mother's history of colon cancer, you are at a slightly increased risk of developing colorectal cancer. However, that does not mean that you need to be screened more frequently than five years if your colonoscopy has been clear or had minimal findings. I cannot give you specific recommendations since I do not know your colonoscopy results, but as a general rule, you should not need to have colonoscopy more frequently unless there are specific findings at that scope which warrant it.
MissouriGal: My mother died of colon cancer. Is there anything that I can do to prevent also getting colon cancer?
Charis_Eng,_MD,_PhD: My advice would depend on the age at which your mother died and whether you have a family history of colon or other cancers. Let’s say your mother is the only person in your family with colon cancer and she developed it after the age of 55. If this were true, getting routine colonoscopies starting at the age of 50 years old (per American Cancer Society Guidelines) would be helpful. Eating a balanced meal with food from the five food groups, especially vegetables and fruits, plus regular exercise are good for everyone.
If your mom’s age at diagnosis is very young (say under the age of 50 years old) and/or there is a family history, then you should ask your doctor for a referral to genetics, and to see a genetic counselor. A cancer genetics clinic will help assess what type of risk you have and what helpful steps you can take.
Salami: If there is a history of colon cancer in your family, how young should you be screened and what tests should you have?
Charis_Eng,_MD,_PhD: There are several inherited colon cancer syndromes, and so it depends on which syndrome one has. For example, if it is determined that a patient has Lynch syndrome, screening colonoscopies can start as early as 25 years old. To determine which colon cancer syndrome you have, you should ask your primary care doctor to refer you for a genetics evaluation. A genetics evaluation entails assessing your and your family’s health history to look for patterns for clues about the genetic risk of colon cancers. Genetic counseling informs and educates patients about what genetics is and the benefits and risks of gene testing.
A professional genetics evaluation will also ensure that the correct gene is tested for. There are many genes which predispose to colon cancer. Therefore, depending on which particular gene is altered, other types of cancers may be involved as well.
tired out: If a person has a family history of colon cancer, would their doctor recommend him or her for genetic testing or is it the person's own responsibility to have it done?
Charis_Eng,_MD,_PhD: If the person has a family history of colon cancer, the most responsible doctor would refer him or her for a genetics evaluation. Often, doctors who do not work in genetics may not recognize that a genetics evaluation is warranted. Often, the public has empowered themselves to seek out genetics evaluation which includes genetic counseling (You can look for a genetic counselor anywhere in the country at the National Society of Genetic Counselors web site). A professional genetics evaluation will also ensure that the correct gene is tested for. There are many genes which predispose someone to colon cancer. Therefore, depending on which particular gene is altered, other types of cancers may be involved as well.
Colon Cancer and Associated Disorders
musakhan: What are hemorrhoid symptoms? Is there a relationship between hemorrhoids and colon cancer?
Matthew_Kalady,_MD: The most common symptoms of hemorrhoids is bright red blood from the anus. This can be detected on the toilet paper when wiping after a bowel movement, or seen in the bowel. Hemorrhoids may also cause itching or irritation around the anus. There is not a relationship between hemorrhoids and colorectal cancer. However, bleeding can also be a symptom of colorectal cancer. A physician can distinguish whether the bleeding is coming from hemorrhoids, or if further investigation of another source is needed.
I freem02: I had precancerous polyps in my early 20s and have Barrett esophagus. Is there any relation between these and colon cancer?
Charis_Eng,_MD,_PhD: Having precancerous polyps in your 20s is very young. That alone tells me that you should seek a cancer genetics evaluation. Barrett esophagus is a precancerous condition as well. There is literature that shows that some families with inherited Barrett esophagus also have an increased risk of colon cancer. However, in our study of over 70 families, we could not show that this connection was true. To summarize, I strongly recommend that you seek a genetics evaluation.
No Name: A friend has Lynch syndrome. How common is this and should people be screened?
Matthew_Kalady,_MD: Lynch syndrome is a rare disease. However, it is the most common hereditary colorectal cancer syndrome. It accounts for approximately three percent of all colorectal cancers. Lynch syndrome is caused by a hereditary genetic defect. It can be passed down from generation to generation. The defect results in the inability to repair DNA. As DNA repair fails, cancers can develop. Cancers develop at an accelerated rate and happen at a much earlier age. The most common cancers of Lynch syndrome are colorectal cancer and uterine cancer. Other less common cancers include ovarian, stomach, small intestine, pancreas, urinary tract and skin. If you have a known diagnosis, screening starts at a much earlier age. For instance, a colonoscopy should be done by age 20 to 25 years old. And that is done every one to two years thereafter. If you have a family history of colon cancer or colon cancer has developed in your family at a young age, you should discuss with your physician about getting tested for Lynch syndrome.
Colonoscopies for Colon Cancer Testing
neptune: I am 77 years old, and had a colonoscopy five years ago which was clear of tumors. At my age is there still value in continuing to have colonoscopies?
Matthew_Kalady,_MD: Based on the information you have provided, your next colonoscopy would be recommended at the age of 87 years old. At that point you would need to evaluate the benefits of colonoscopy based on your overall health. If you are expected to live to be 100 years old and are still in good shape at 87, then it would be recommend that you have a colonoscopy, assuming you would have treatment if you found colon cancer.
neptune: If one has chronic kidney disease, the standard preparation fluid for colonoscopy that patient’s need to drink is considered a problem. Isn’t there a high concentration of salt?
Matthew_Kalady,_MD: High-salt solutions can be hazardous for patients with kidney disease. The recommended preparation for patients with kidney disease is GoLYTELY®. This should be discussed with the doctor ordering your colonoscopy.
GroKenhammer: What is the frequency for colonoscopy after you have had two or more polyps?
Matthew_Kalady,_MD: The frequency and interval between colonoscopies varies and depends on a number of factors including your personal or family history of polyps or colorectal cancer, the findings during your most recent colonoscopy, and the quality of the bowel preparation. For patients who do not come from a family with a known hereditary syndrome or family history of colorectal cancer, regular screening should start at the age of 50 years old. The next colonoscopy depends on the types of polyps, the number found, their size, and how easily they could be removed. The interval of time between colonoscopies can be anywhere from one year to five years. These specifics should be discussed on an individual basis with your physician.
Stool Sample Testing
GroKenHaMMer: How reliable is the recent test of a stool sample for colon cancer?
Matthew_Kalady,_MD: There are many different screening tests available to detect colon cancer. Depending on the type of platform used and the studies that are published, the accuracy can be anywhere from 50 to 90 percent. The two available stool tests in the United States include Fecal Occult Blood Test (FOBT) and Fecal Immunochemical Test (FIT). Both tests detect blood in the gastrointestinal tract. Neither one is specific to blood from the colon, and can be positive if there is a bleeding source in the stomach or small intestine. The FOBT can get a false positive reading based on your diet. The FIT performs better in that it does not have the false positive results based on diet.
The disadvantages of these tests are that they do not detect all cancers and are not very good at detecting adenomas (precancerous polyps). Although these tests can be used for screening on a yearly basis, a colonoscopy provides better information in terms of picking up small polyps or small cancers. Colonoscopy also allows for an opportunity to remove or biopsy these polyps or cancers.
Genetic Testing for Colon Cancer
MrsSanta: Do most insurance plans cover genetic screening?
Charis_Eng,_MD,_PhD: Most insurance companies will reimburse at least part—and often all—of the costs of both gene testing and important, genetic counseling. Genetic counseling must occur before testing.
gunther: What is involved in the genetic testing? What can I expect?
Charis_Eng,_MD,_PhD: Never ask your doctor for a genetics test. Ask instead to be referred for a cancer genetics evaluation by genetics professionals which includes genetic counseling.
A genetics evaluation entails assessing your and your family’s health history to look for patterns that provide clues about the genetic risk of colon cancers. Genetic counseling informs and educates patients about what genetics is, and the benefits and risks of gene testing.
A professional genetics evaluation will also ensure that the correct gene is tested for. There are many genes which predispose someone to colon cancer. Therefore, depending on which particular gene is altered, other types of cancers may be involved as well.
Most genetic tests involve a blood draw. Genetic testing usually takes two to eight weeks to complete (as compared to 10 years ago when it took one year to complete). Once the result comes back, the genetics professional will interpret the results and provide advice on how your doctors can use the gene test results to personalize your treatment.
gunther: If someone is genetically tested for colon cancer and found to be at high risk, what happens next?
Charis_Eng,_MD,_PhD: Genetic testing for colon cancer will give an accurate diagnosis of the type of hereditary colon cancer a patient has. Depending on which gene is involved, it will tell your healthcare providers how to personalize your treatment. Usually, it will tell the doctor to begin routine colonoscopies at a younger age (e.g., at the age of 25 years old instead of 50 years old because certain colon cancers can occur before the age of 30 years old) and at greater frequency (e.g., annually instead of every 10 years). Also depending on the specific gene, it will also tell your healthcare provider what other organs need to be watched. Genetic knowledge is power.
Knowing which gene is altered will also allow the genetics professionals to offer gene testing (only looking at that one spot in that specific gene) to your unaffected family members. This is a 100-percent accurate test, and will let your family members know whether they carry the same gene risk or not. If they do, then they can receive the same close clinical screening to catch cancers early when they are curable or may even prevent cancer from occurring.
neptune: What would be a recommended diet to avoid problems in the colon. I believe the literature indicates red meat can be a problem. Do studies show that is true?
Matthew_Kalady,_MD: There are multiple studies about the association of diet and colorectal cancer. These studies provide varying levels of evidence and are often difficult to interpret because people in these studies are influenced by many different factors. It is a challenge to isolate a single factor. In general, everything in moderation is a good rule. Red meat, particularly grilled red meat, has been associated with an increased risk. When bigger portions are consumed and there is an increased frequency in eating red meat, it results in a greater risk. A recommended diet includes one that supports general health, including foods high in fiber, as well as fruits and vegetables. Your diet should avoid excessive consumption of high-fat foods and red meats.
Moderator: I'm sorry to say that our time with Cleveland Clinic experts Dr. Charis Eng and Dr. Matthew Kalady is now over. Thank you both for taking your time to answer our questions today about colon cancer and genetics.
Charis_Eng,_MD,_PhD: Thank you. The genetics professionals at the Cleveland Clinic are happy to serve you. Please visit my.clevelandclinic.org/genomics-genetics/ for more information. You can reach us at phone number (216) 636-1768 and also (800) 998-4785.
Matthew_Kalady,_MD: Thank you for your time and interest in colorectal cancer. I appreciate your interest in learning more. I encourage you to learn about your family and family history. Colorectal cancer is a curable disease if caught early and I cannot emphasize enough to undergo appropriate screening.
To make an appointment with Charis Eng, MD, PhD, or any of the specialists in the Genomic Medicine Institute at Cleveland Clinic, please call 216.636.1768 or 800.998.4785 (toll-free). You can also visit us online at my.clevelandclinic.org/genomics-genetics/genetic-genomic-medicine.aspx.
To make an appointment with Matthew Kalady, MD, or any of the specialists in the Digestive Disease Institute at Cleveland Clinic, please call 216.444.7000 or call toll-free at 866.382.0089. You can also visit us online at www.clevelandclinic.org/digestive_diseases/ or learn more about colon cancer at www.clevelandclinic.org/score.
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