Although they are at a greatly increased risk for ovarian cancer and cancer of the uterine lining, most women from families with an inherited mutation for Lynch syndrome or hereditary non-polyposis colon cancer (HNPCC) don’t understand that risk or get screened for those cancers.
Researchers at the National Human Genome Research Institute and the National Cancer Institute interviewed women who had a family member with Lynch syndrome before and after their own genetic testing. Because they had a first-degree relative who had already tested positive for one of the mutations that causes Lynch syndrome, the women were at 50 percent risk of having a mutated gene themselves.
Before counseling very few women (five percent) with an inherited risk for Lynch syndrome thought that they might have an increased risk for cancer outside the colon. But nearly all (86 percent) understood that they had a risk for colon cancer greater than the average person.
While more than half had had a colonoscopy — two-thirds of those who were over 25 had colonoscopy — only a third had screening for endometrial cancer.
Lynch syndrome is a genetic mutation directly passed from parents to their children. Mutation carriers have an increased risk to be diagnosed early with many cancers including colon, endometrial, small intestine, ovary, liver, pancreas, kidney, ureter, and brain. Four genes (MLH1, MSH2, MSH6, and PMS2), whose job it is to detect and repair damaged DNA, are linked to the syndrome. People with a mutation in one of these genes have a lifetime risk close to 90 percent for Lynch syndrome associated cancer.
Dr. Henry Lynch first used the term hereditary nonpolyposis colon cancer to differentiate it from familial adenomatous polyposis (FAP), another inherited mutation causing many polyps and leading to colon cancer. More recently, the term Lynch syndrome has been used to more accurately describe the disease which does arise from polyps and includes cancers outside of the colon.
Guidelines recommend that women who have a Lynch syndrome mutation or who are at high risk for one because of family history begin colonoscopies at age 20 to 25 and repeat them every 1 to 3 years. In addition, they should begin screening for endometrial and ovarian cancers between age 25 and 35 and repeat them every year. Those who test negative for the family mutation are at no higher risk than the general population and can begin colorectal cancer screening at 50.
Screening for endometrial cancer can be via transvaginal ultrasound or uterine biopsy or both.
Writing in the Journal of Clinical Oncology, Donald Hadley and his colleagues said,
Women in families with Lynch syndrome are less aware of their risks for extracolonic cancers and undergo endometrial cancer screening significantly less often than colonoscopy before genetic counseling. Given the significantly increased risks for endometrial and ovarian cancers and the mortality associated with ovarian cancer, additional efforts to inform families of cancer risks and screening recommendations seem prudent. Physicians play a critical role in ensuring appropriate cancer screening in women with Lynch syndrome.
SOURCE: Hadley et al. Journal of Clinical Oncology, Volume 26, Number 6, February 20, 2008.
