The screening for Lynch syndrome started after a 2005 study by cancer researchers at Ohio State’s Comprehensive Cancer Center found that 2 to 3 percent (at least one in 45) of people with colon cancer probably have mutations for the inherited syndrome. The screening test helps determine if the person and his or her relatives should consider genetic counseling and testing for the syndrome.
The James is one of the first hospitals nationwide to routinely screen for Lynch syndrome at the time of diagnosis, says Heather Hampel, a genetic counselor in the clinical cancer genetics program at Ohio State and first author of the study which was published in the New England Journal of Medicine.
“This is really important not just for patients, but for their family members as well. Many colon cancer patients are surviving longer, and they would have an increased risk of getting second cancers later in life if they have the hereditary type,” Hampel says.
“In addition, if they have the hereditary type of cancer, their children, siblings, parents, aunts and uncles, nieces and nephews, and cousins may also be at risk. Those relatives would have an 85 percent lifetime risk of developing colon cancer and a 60 percent lifetime of risk of uterine cancer if they inherited Lynch syndrome,” Hampel says.
The screening is conducted following surgery using a relatively inexpensive test in the pathology laboratory. The test, an immunohistochemistry test, stains hair-thin slices the tumor for four proteins that are normally present in a colon cancer tumor. But in most hereditary cases, one or two of the proteins are missing, Hampel says.
“It’s very easy to tell from the test if the proteins are present or absent in the tumor,” Hampel says. “About 80 percent of tumors will have all four proteins present, and those patients are less likely to have the hereditary form of colon cancer. About 20 percent of tumors will have one or two proteins missing, and those patients are more likely to have the hereditary form of cancer.”
In addition, the test can help predict prognosis, she says. Those with one or two of the proteins missing on this test tend to have a better prognosis than those with all four proteins present, Hampel says.
Those who are more likely to have hereditary colon cancer are referred to the clinical cancer genetics program, where they can meet with a genetics counselor and learn more about their risk. In addition, they can decide whether or not to pursue genetic testing to determine whether or not they have Lynch syndrome. If a gene change is found, then their family members can also be screened for the mutation, Hampel says.
People with Lynch syndrome should start having annual colonoscopies at age 25, while those without the gene mutation should follow the American Cancer Society recommendations for the general population, which calls for colonoscopies every 10 years starting at age 50, Hampel says.
“By having them start with annual colonoscopies at an earlier age, we can identify any polyps and remove them, which will prevent the colon cancer from happening in the first place,” Hampel says. “This is where doctors can really intervene and make a difference.” Individuals with Lynch syndrome also need increased surveillance for the other associated cancers, which are endometrial, stomach and ovarian.
The 2005 study showed that 23 of the 1,066 patients (2.2 percent) newly diagnosed with colorectal cancer from six hospitals in the Columbus, Ohio, area had Lynch syndrome mutations.
“Of those 23 patients, we’ve tested around 200 at-risk relatives and identified 100 people who have inherited Lynch syndrome and should receive increased cancer surveillance,” Hampel says. “The other 100 relatives found out they had not inherited Lynch syndrome and can follow screening recommendations for the general population, which means they don’t have to undergo unnecessary screenings.”