March is Colorectal Cancer Awareness Month

Colorectal cancer is the third most common cancer (excluding skin cancers) and the second leading cause of cancer-related deaths in the United States. Each year about 150,000 people are diagnosed with the disease.

Risk factors for colorectal cancer include age (most cases occur in people over 50), ethnicity (African Americans and Ashkenazi Jews have particularly high rates of the disease), a personal history of colon polyps or colorectal cancer, and the presence of inflammatory bowel disease (Crohn’s disease or ulcerative colitis).  Obesity, physical inactivity, smoking and heavy drinking have also all been associated with increased risk for colorectal cancer.

Genetics contribute to a person’s colorectal cancer risk, although non-genetic factors seem to play a larger role.  About 5% of people with colorectal cancer, however, develop the disease as a result of either familial adenomatous polyposis (FAP) or Lynch syndrome, two cancer syndromes caused by serious genetic mutations.

Anyone with a family history of colorectal cancer should talk to their health care professional about what screening procedures, and possibly what genetic tests, are right for them.

Research to find common genetic variants associated with colorectal cancer risk has yielded several good associations, but together they explain only a small part of the genetic contribution to the disease. There are probably many more variants with small effects left to be found, as well as rare variants with larger effects.  23andMe customers can see their results for three replicated SNP associations in the Colorectal Cancer Research Report.  Spittoon posts addressing colorectal cancer can be found here, here, here and here.

Learn More About Your Risk

Several online tools are available to help you get a better idea of your risk for colorectal cancer.

Get Involved

You can contact the following organizations to learn more about colorectal cancer and find out how to get involved in Colorectal Cancer Awareness Month.

And for those who want an up-close lesson about colorectal cancer, click here to see if the Prevent Cancer Super Colon™ is coming to a town near you.


  • Don Gentry

    I was looking at your site to determine the scope of SNP’s you include. It appears you do not screen for MLH1 or 2, or MSH2 mutations. I am interested if you have plans to include this soon, as these seem to indicate very high genetic risk for CRC (HNPCC) and uterine cancer.

    • http://23andme.com Shwu

      Hi Don,

      Thanks for your question. Our Colorectal Cancer report currently only includes common genetic variants that influence susceptibility to the disease. We do hope to be able to add reports that cover rare but important genetic mutations for hereditary cancers in the future but it will depend on what we are able to detect with our genotyping chip.

  • B.D.

    Can your testing kit detect Lynch Syndrome? My mother’s family appears to have it.. However, it seems to be skipping generations. I’d like to be tested for it. Do you have any suggestions?

    • ScottH

      B.D. Sorry to hear about your mother. We do not currently test for the genetic variants associated with Lynch Syndrome. 23andMe reports on genetic factors related to more than 200 diseases, traits, and health conditions and we regularly add new information as our Health Product team evaluates the scientific literature and the capabilities of our SNP genotyping technology.However, there are many genetic conditions, that we don’t currently test for. If you’d like more details about this you can go to this link. For more on conditions and traits we do test for go here.

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