Are your genetics putting you at risk for colorectal cancer?

cancer geneticsColorectal cancer is the second leading cause of cancer-related deaths in the United States, trailing only lung cancer in the number of deaths each year. The American Cancer Society estimates 50,310 people will die from colorectal cancer in 2014 alone. Unlike lung cancer, however, there are ways to successfully screen for and prevent this common disease.

In conjunction with Colorectal Cancer Awareness Month, I have outlined some factors health care providers consider in assessing an individual’s risk for colorectal cancer and determining the best approaches for screening and prevention.

Screening = Prevention

Colon cancer screening has been very effective in reducing the number of colorectal cancer diagnoses and deaths in the United States. In fact, colorectal cancer can be largely prevented through proper screening. Yes, that’s right: prevented. Colonoscopy, the gold standard in colon cancer screening, can not only detect cancer but can also remove precancerous polyps, preventing them from growing into cancers.

There are a variety of tests available to screen for colorectal cancer. If all individuals underwent screening as recommended by medical experts, more than 90% of colon cancer deaths could be prevented.

Screening for colon cancer should begin at age 50 for people of average risk. Those with certain risk factors (including a family history of the disease or certain medical conditions) may need to begin screening earlier.

Genetics pinpoint higher risk

While most colorectal cancer diagnoses are made in individuals without obvious risk factors, approximately one-third of cases arise in individuals with a family history of the disease and about 10% are associated with inherited mutations in genes which predispose to the development of cancer. In other words, if colon cancer runs in your family, it might be a faulty gene at work. Genetic counseling and testing can help identify people at higher genetic risk for colorectal cancer who may benefit from earlier and more frequent screening. Two conditions associated with genetic predisposition to colorectal cancer are familial adenomatous polyposis and Lynch syndrome. These conditions are uncommon (they account for fewer than 5% of all colorectal cancer cases), but can be detected through genetic testing. Starting colorectal cancer screening at earlier ages, with more frequent testing, can successfully prevent the majority of cancers even in individuals with genetic predisposition.

People concerned about a family history of cancer, or those who have been diagnosed with colon cancer before age 50, should talk to their doctor about the possible benefits of genetic evaluation. Genetic evaluation typically involves:

  • a thorough review of a patient’s personal and family history
  • a physical examination to look for signs and symptoms of familial cancer and determine whether genetic testing is indicated
  • individualized counseling about strategies to lower the risk of cancer

In Michigan, Governor Rick Snyder has declared March 22nd Lynch Syndrome Hereditary Cancer Awareness Day to raise awareness of Lynch syndrome in the state. Through this designation, Michigan encourages all residents to learn more about their family history of cancer  and to share this information with their healthcare provider who can assess risk and take steps toward prevention and detection.

About 22,500 people in Michigan are estimated to have Lynch syndrome, a hereditary condition associated with a high risk for developing colorectal and other types of cancer. Most of those at risk remain undiagnosed. For families with multiple cases of colorectal cancer, genetic evaluation can help determine if specialized screening would be beneficial.

Treatments improving

Early detection and more effective treatments have resulted in higher cure rates of colon cancer over the last 20 years; so much so that there are now more than 1 million survivors of colorectal cancer in the United States.

Researchers continue to work to find better ways to treat colorectal cancer. At U-M, radiation oncologists have developed new techniques to treat tumors that spread to the liver. Better surgical techniques have also allowed for resection, or surgical removal, of advanced disease.

New drugs have also been developed to treat colorectal cancer, most targeting molecular pathways involved in fueling the disease. We are using molecular tests to better characterize tumors and determine which patients are most likely to relapse and which will benefit most from specific types of chemotherapy. These tests are especially important for patients with stage II disease where the benefits of chemotherapy may be marginal. If we can tell which patients have a very low risk of recurrence, we can potentially spare them from chemotherapy and it side effects.

Take the next step:

  • Call the nurses at Cancer AnswerLine with questions on colon cancer, screenings and prevention at 800-865-1125.
  • Make an appointment for a colonoscopy at 877-220-2920.

Continue reading about colon cancer and genetic risk

Elena StoffelElena Stoffel, M.D., is an assistant professor of Internal Medicine at the University of Michigan. Dr. Stoffel received her medical degree from Harvard Medical School and performed her internal medicine residency at Brigham and Women’s Hospital in Boston, MA. She also completed a fellowship in Internal Medicine Gastroenterology at Brigham and Women’s Hospital. Her research interests include cancer epidemiology and genetics, endoscopic screening and chemoprevention.


Cancer-center-informal-vertical-sig-150x150The University of Michigan Comprehensive Cancer Center’s doctors, nurses, care givers and researchers are united by one thought: to deliver the highest quality, compassionate care while working to conquer cancer through innovation and collaboration. The center is among the top-ranked national cancer programs, and #1 in Michigan for cancer patient care. Seventeen multidisciplinary clinics offer one-stop access to teams of specialists for personalized treatment plans, part of the ideal patient care experience. Patients also benefit through access to promising new cancer therapies.