Lynch syndrome is an inherited disorder in which affected individuals have a higher-than-normal chance of developing colorectal cancer and certain other types of cancer, often before age 50. Approximately 2 to 4 percent of all cases of colorectal cancer and 2 to 3 percent of all cases of endometrial cancer are thought to be due to Lynch syndrome, according to the National Comprehensive Cancer Network (NCCN).
Lynch Syndrome: What Cancers Are You at Risk For?
A person with Lynch syndrome has up to an 80 percent lifetime risk for colon cancer and up to a 60 percent chance for endometrial cancer, according to the American Society of Clinical Oncology (ASCO). Lynch syndrome increases the risk for endometrial cancer and other cancers up to 10 times over the general population. Risks are also moderately increased for gastric cancer and ovarian cancer, and slightly increased for small bowel, brain, urinary, hepatobiliary tract (liver, bile ducts, and gallbladder), and sebaceous gland tumors. But not everyone with Lynch syndrome will develop cancer.
What Causes Lynch Syndrome?
Lynch syndrome is caused by inherited DNA alterations in one of at least five genes that, when functional, ensure the repair of DNA mistakes during cell division. Known as mismatches, it’s as if these cells lack a spell-check. An altered Lynch syndrome gene causes cells to acquire more mistakes, which leads to cancer.
When a parent has Lynch syndrome or carries a genetic alteration in one of their related genes, there is a 50 percent chance that each of their children will inherit the altered gene and also have Lynch syndrome.
How Prevalent Is Lynch Syndrome—and How Can You Find Out if You Have It?
It is estimated that 1 in every 280 Americans has the disorder. This means about 1.1 million people, fewer than 5 percent of whom are aware that they are affected, according to the National Cancer Institute (NCI). Lynch syndrome is typically first diagnosed with a staining test on tumor biopsies from colon cancer or endometrial cancer. If this tumor test is abnormal, then the patient will be instructed to follow up with a genetic counselor, who will offer blood testing to confirm the presence of genetic alterations consistent with Lynch syndrome. There are genetic tests available to screen for the disease in people who have not developed cancer. This is typically done when a member of a family has been identified as having the syndrome.
Lynch Syndrome: What Are the Signs?
Multiple cancers in the same person (especially if diagnosed at the same time), early age of onset of colon cancer, and having several family members affected with colon cancer are all signs that a Lynch syndrome mutation may run in the family. Additionally, a family in which three or more family members (on the same side of the family) have been diagnosed with colon, endometrial, ovarian, or gastric cancers before age 60 indicates a possibility of Lynch syndrome. If no one in the family with cancer is living, it’s recommended that relatives with a suspicious family history of Lynch syndrome should meet with a genetic counselor to discuss undergoing genetic testing.
Lynch Syndrome: Managing Risk
According to the NCCN’s guidelines:
People who test positive for Lynch syndrome should have colonoscopies starting at age 20 to 25, and an upper endoscopy every three to five years beginning at age 30 to 35.
Women are encouraged to be screened for endometrial cancers every 1 to 2 years beginning at age 30. Currently, there is no effective screening for ovarian cancer, so it’s important for women with Lynch syndrome to familiarize themselves with potential symptoms of ovarian cancer. Sometimes a transvaginal ultrasound is used as an adjunct screening for ovarian cancer but it is not very sensitive. Women with Lynch syndrome should also give strong consideration to a prophylactic hysterectomy with bilateral oophorectomy, or the removal of ovaries, once childbearing is complete.
Both men and women should undergo an annual urinalysis and neurological exams beginning at age 25 to 30 and an annual physical exam that includes a full skin exam to look for malignant and benign skin manifestations. Low-dose aspirin is also recommended for colorectal cancer prevention, according to the ASCO. Pancreatic cancer screening should begin at age 40 with yearly magnetic resonance imaging scans (MRIs) or magnetic resonance cholangiopancreatography (MRCP) scans.
A Vaccine on the Horizon?
Researchers are working on a vaccine to prevent cancer in people with Lynch syndrome, according to the NCI. So far, the vaccine has prevented the growth of colorectal tumors and prolonged survival in mice compared with unvaccinated mice. Naproxen also appeared to enhance the efficacy of the vaccine.