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Cancer Genetics

Colon and Breast Cancer Link



Is there any relationship between breast cancer and colon cancer in women. My mom had colon cancer in 1993 and has been recently diagnosed with breast cancer, which will result in a mastectomy. When she had the colon cancer, the only treatment was surgery, no chemo or radiation?


Statistically, women who have had colon cancer do have a very slightly increased risk for developing breast cancer. Because these are both very common cancers, they can occur in the same person by chance. In the general population, women have a 10% lifetime risk for developing breast cancer and a 6% lifetime risk for developing colon cancer.

Sometimes when one individual is diagnosed with two separate cancers, this can be a sign of a hereditary cancer susceptibility. If you have additional family history of breast, colon, ovarian or uterine cancers; or if your mother was diagnosed with these cancers under age 50; or if your ancestry is Ashkenazi Jewish (some hereditary cancer syndromes are more common in this ethnic group), you may benefit from a consultation with your local cancer genetic counselor. Colon cancer has been noted in families with hereditary breast-ovarian cancer and breast cancer has been noted in families with a hereditary colon cancer syndrome (known as hereditary non-polyposis colorectal cancer syndrome). In addition, there are researchers studying families with multiple cases of breast and colon cancer (in many relatives) because they think this may represent a new cancer susceptibility syndrome.

Even if you don`t have any additional family history, it will be important that you and your siblings notify your physicians that your mother has had breast and colon cancer. Depending on her age at diagnosis, you may need earlier or more frequent screening for these cancers. In the general population, the American Cancer Society recommends that women perform monthly breast self-examination beginning at age 18, receive annual clinical breast examinations from a physician beginning at age 20, and receive annual mammography beginning at age 40. The American Cancer Society recommends that men and women in the general population receive colorectal cancer screening including annual fecal occult blood tests (testing the stool for blood) and sigmoidoscopy (or colonoscopy) every 3-5 years beginning at age 50.

Finally, you may want to ask her physician if these are two separate primary cancers or if the breast cancer could be a metastasis (or spread site) from her colon cancer. It is very rare for colon cancer to spread to the breast so they are probably separate primary cancers. In this case, the treatment that your mother received for her colon cancer did not have anything to do with her development of breast cancer.

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Response by:

Heather L Hampel, MS, CGC Heather L Hampel, MS, CGC
Cancer Genetic Counselor
College of Medicine
The Ohio State University