Lynch syndrome, also known as Hereditary Nonpolyposis Colorectal Cancer (HNPCC), is an inherited condition that causes an increased risk for several different types of cancer at earlier ages than people typically develop cancer. Lynch syndrome accounts for approximately 3 percent of all colorectal cancers and approximately 2 percent of all uterine cancers that are diagnosed each year. Lynch syndrome is caused by mutations or changes in one of several genes known as mismatch repair genes (MLH1, PMS2, MSH2, MSH6 and EPCAM).
What cancer risks are associated with Lynch Syndrome?
Individuals with Lynch syndrome have a 50-80 percent risk for colorectal cancer, and women have a 25-60 percent risk for uterine cancer. Colon cancer, whether it is due to Lynch syndrome or not, usually develops because precancerous colon polyps are not removed during routine colonoscopy. Individuals who have Lynch syndrome generally do not develop a larger quantity of polyps than the average person; however, those colon polyps typically develop into colon cancer quicker than the average person (two to five years instead of 10 to 15 years). Other cancers including stomach, ovarian, kidney/urinary tract, biliary tract, brain, small bowel, pancreatic and sebaceous adenoma/carcinoma may also occur more frequently in individuals who have Lynch syndrome.
What is the benefit of knowing I have Lynch syndrome?
If you have Lynch syndrome, Parkview’s genetic counselors will discuss recommendations for additional screening and/or preventative strategies that can greatly decrease your risk for cancer. These recommendations include:
- Colon cancer:
- Colonoscopy every one to two years starting as early as 20-25 years of age
- Uterine/Ovarian Cancer:
- Consideration of surgery to remove the uterus and ovaries after childbearing is complete
Colonoscopy is a procedure that examines your colon and screens for the presence of colon polyps. If polyps are found, they are removed; therefore, preventing those polyps from developing into colon cancer.
Who should consider being tested for Lynch syndrome?
We recommend genetic counseling to evaluate your specific risk and to discuss the possibility of genetic testing.
Genetic counseling is appropriate if you have:
- Colon or uterine tumors found to have abnormal Lynch syndrome pathology testing
- Lynch syndrome screening is routinely performed by pathology on all colon tumors removed from someone under 70 years of age at Parkview Regional Medical Center.
- A personal history of colon or uterine cancer diagnosed prior to age 50
- A family history of colon or uterine cancer prior to age 50
- A family history of more than three close relatives diagnosed with a Lynch syndrome cancer
- A family history of Lynch syndrome
If I am found to have a mutation in a Lynch syndrome gene, what does that mean for my family?
Mutations in the mismatch repair genes are passed down in families, and anyone who has a mutation likely inherited that mutation from one of their parents. If you have Lynch syndrome there is a 50 percent chance that each of your children has it, and a 50 percent chance they do not have it. In addition, your siblings also have a 50 percent chance of having Lynch syndrome. We recommend that your family members meet with a genetic counselor to discuss possible testing.
People within the same family will often react differently to this kind of information, and whether each family member chooses to pursue testing themselves is a personal choice. As there is no risk for cancer to occur in children who have Lynch syndrome, we do not test people younger than 18 years of age for mutations in the mismatch repair genes.
To schedule an appointment with a genetic counselor, please call Parkview Genetic Counseling at (260) 266-9225. For more information, please read our frequently asked questions.