The following cancers are associated with Lynch syndrome:
- Colon cancer
- Ovarian cancer
- Uterine cancer
MLH1 gene change
The MLH1 gene is a “mismatch repair gene” – it helps cells repair mistakes in DNA. When the MLH1 gene is not working to repair mistakes in the DNA, errors can add up in the DNA of cells in different parts of the body. This causes an increased risk of developing certain types of cancer.
A change in the MLH1, MSH2, MSH6 or PMS2 genes is associated with Lynch syndrome. This causes an increased risk of developing certain cancers that are passed through a family.
Risk in the general population
Colon cancer: 5.5%
Uterine cancer: 2.7%
Ovarian cancer: 1.3%
Sebaceous neoplasm: <1%
Pancreatic cancer: <1%
Stomach cancer: <1%
Other: brain, small bowel, hepatobiliary and urinary tract cancer: <1%
Risk with MLH1 gene change
Colon cancer: 50-80%
Uterine cancer: 25-60%
Ovarian cancer: up to 24%
Sebaceous neoplasm: up to 9%
Pancreatic cancer: up to 6%
Stomach cancer: up to 13%
Other: brain, small bowel, hepatobiliary and urinary tract cancer: up to 7%
Understanding your risk
Colon, uterine and ovarian cancers are the main cancers associated with Lynch syndrome. However, it is possible to have Lynch syndrome and never develop cancer because there is not a 100 percent risk for any cancer. If you have Lynch syndrome, cancer screening with colonoscopy is recommended for men and women, starting at age 25. Childhood cancers are not known to be associated with Lynch. With appropriate screening and management, many cancers can be prevented or detected at an early, treatable stage. Knowledge of your higher cancer risk will help you and your doctors to develop a plan that is right for you.
Living with lynch syndrome
Healthy habits, such as maintaining a healthy weight, getting regular exercise and minimizing alcohol consumption, can help minimize your risk of cancer. Aspirin use may also prevent colon cancer but should be discussed with your doctors.
The information below is referenced from the National Comprehensive Cancer Network guidelines for cancer screening and prevention for individuals with MLH1 variants. These guidelines change over time, so it is important to continue to talk with your doctors about your cancer screening options.
Screening and prevention options:
- Colonoscopies starting at 20 to 25 years old, repeated every 1 to 2 years
- Consider an annual urinalysis starting at 30 to 35 years old
- Consider an annual physical with neurological evaluation starting at 25 to 30 years old
- For women, consider surgery to remove the uterus and ovaries after having kids
What does this mean for my family?
Family members related by blood may have the same genetic change. If you receive a genetic variant result, we strongly encourage you to share this information with your close blood relatives. Your children and siblings each have a 50 percent chance to have the same genetic change. More distant relatives may also be at risk. Family members related by blood can have genetic testing for the specific gene change that has been identified and can use results to guide their care.
Find a provider
It is important for anyone who has Lynch Syndrome to follow specific early cancer screening and prevention guidelines.
There are doctors throughout the Geisinger system who specialize in helping people with MLH1 variants to develop a screening and management plan that is right for them. Consider talking about this result with:
- Primary care providers - These providers will manage your overall care
- Geisinger Inherited Risk GI Clinic - This clinic is designed especially for people with MLH1 variants to meet with doctors and a genetic counselor who specialize in Lynch syndrome. Here, we talk about specific cancer risks and answer questions about Lynch syndrome. If you have any questions about the clinic, call our cancer genetics department at 570-214-2637 and ask to speak to a genetic counselor about the Inherited Risk GI Clinic.
- Gastroenterologist or Colorectal Surgeon - These doctors can discuss colon screening using colonoscopies.
- If you are a female, a gynecologist can discuss removal of your uterus and ovaries after you are finished having children.