All cancers result from a combination of genetic and environmental influences, and genes that can predispose us to cancer can be inherited from our parents. It’s important to know and understand your family’s medical history because it provides clues that you may be at elevated risk to develop a particular disease. We should all try to know the cancers which have occurred in our families for at least three generations.

For older women this may be more difficult, as in years gone by cancers weren’t discussed as freely as they are now. To help your physician get the full picture, it’s important to bring your complete family medical history to your appointment, so that you can review it together and determine if you’re at risk for a particular disease. This way, a health care strategy aimed at prevention and early detection can be tailored specifically for you

Over the past ten years much attention has been paid to hereditary breast and ovarian cancers. This is largely due to the identification of the BRCA1 and BRCA2 genes and an increased understanding of the impact that they can have on breast and ovarian cancers. For some time now, we have known that colon cancer can also occur in a hereditary pattern. Approximately 60 percent of colon cancers occur in women without a family history of the disease. But 30 percent appear in women with some family history, and an additional 10 percent occur in a hereditary pattern in which cancers are found in virtually each generation.

Histopathologic image of colonic carcinoid.

Unfortunately, physicians and health care practitioners are not as versed in helping patients in assessing their colon cancer risk. This may be due to the fact that some hereditary-colon-cancer syndromes are more complex and consist of other cancers, such as gastric cancer, small bowel cancers, urologic cancers, and importantly for women, endometrial cancers. For reasons that are not entirely clear to us, some patients will inherit a faulty gene and develop colon cancer, and others in the family may develop, for example, a urologic cancer. This is most likely due to a combination of environmental exposure and genes. That’s why these groupings are called “syndromes,” and why they may be difficult to diagnose.

The most common form of hereditary colon cancer is known as the Lynch Syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC). Red flags for HNPCC include a history of colon cancers that occur in family members under 50 years old, early onset endometrial cancers in family members under 50, and two or more HNPCC related cancers (colorectal, endometrial, gastric, ovarian, ureter/renal pelvis, biliary tract, small bowel, pancreas, brain, and sebaceous adenoma) in the family. Women who have any of these “red flags” in their familial histories may have an up-to-80% chance of developing colorectal cancer and up-to-71% chance of developing endometrial cancer. Women who may be members of a HNPCC family may should be referred to specialists who can review with them the risks and benefits of genetic testing for the genes responsible for HNPCC and also plan  surveillance and early detection strategies. They will benefit from more intensive screening and possibly from prophylactic surgery.

The take-home message: Know your cancer family history for three generations and review it with your physician. If there is a history of colon polyps or colon cancer in your family, you should not wait until age 50 to have a colonoscopy—it should be done sooner and potentially more frequently. If you may be a member of an HNPCC family, review with your physician your endometrial cancer risk. Be proactive in your care, be aware of illnesses that you may be at increased risk for, and bring them to the attention of your physician.

A member of the WVFC Medical Advisory Board, Dr. Elizabeth Poynor is a practicing gynecologic oncologist and pelvic surgeon, with a Ph.D. in cell biology and genetics. Her private practice in New York focuses  on cancer diagnosis, prevention and treatment.

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