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The power of genetic testing and knowing your cancer risk

March 31, 2016 | Patricia Harriman
A grandfather, mother, father and young son

As many as one in five people who develop colorectal cancer have other family members who has had this disease. The risk is even greater if a relative was diagnosed younger than age 45, or if more than one first-degree relative has had colorectal cancer.

Lynch syndrome is an inherited disorder that dramatically increases the risks of many types of cancer, particularly cancers of the colon, and is almost as prevalent as hereditary breast and ovarian cancer (HBOC).

However, twice as many patients are undergoing testing for breast and ovarian cancer as for Lynch syndrome and other gastrointestinal cancer syndromes, according to a recent study presented at the 2015 annual meeting of the American College of Gastroenterology.

Correct diagnosis essential

“Getting the correct diagnosis for the possible Lynch syndrome gene mutation is essential in managing cancer risk,” says UCI Health gastroenterologist Dr. William Karnes, director of the high risk colon program.

“If you have a family history of colorectal cancer, genetic counseling can be beneficial to determine how likely it is that you have a family cancer syndrome.”

Karnes’ patient Craig Gilbert lost his father, both grandparents and an uncle to colon cancer. He was pretty sure he was at a high risk for cancer.

Genetic test results from UCI Health confirmed his hunch. Gilbert found out he has Lynch syndrome, which puts him at an 80 percent chance of developing colon cancer in his lifetime.

The mutation can also contribute to certain types of stomach and hepatobiliary cancers, and to uterine and ovarian cancer in women.

The value of genetic testing

Gilbert’s diagnosis prompted three of his four siblings back in Boston to get tested. One sister doesn’t have Lynch syndrome. Two sisters not only tested positive for Lynch syndrome, they were both diagnosed with endometrial cancer, requiring surgery, chemotherapy and radiation. His brother still hasn’t been tested.

“If it wasn’t for my testing with the Irvine team and the discovery of Lynch syndrome, my sisters would have never known they had cancer,” Gilbert said.

“They would have ignored the symptoms until it was far too late. If we had known about Lynch in our family five years ago, my sisters would have been proactive and gotten hysterectomies before they got cancer. They and I can’t thank the UCI Health team enough for diagnosing my genetic issues.”

Proactive management

Gilbert had his first colonoscopy at 35, when he experienced symptoms. Polyps were discovered and removed when he was 40. He says the reason he had genetic testing was to find out exactly what risk factors he had inherited.

“Now, at age 45, I get a colonoscopy every year,” he says. “If genetic testing hadn’t progressed as far as it has, I would probably die young, at age 50, like my dad. Knowing my risk is empowering, because now I can proactively manage my condition.”

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