Does having Lynch Syndrome mean I will definitely get colon cancer?

Lynch Syndrome is a genetic condition that makes you more likely to develop certain cancers, including colon cancer. However, having the gene mutation does not guarantee that cancer will develop. Research shows that while the risk is high, it is not 100%. The best way to manage this risk is through regular screening.

What the research says

Lynch Syndrome is caused by changes in genes that repair DNA errors. People with these changes have a much higher risk of colorectal cancer than the general population, but they do not all develop the disease. A large study of over 4,700 people found that regular colonoscopies did not stop cancer from starting, but they did significantly lower the risk of dying from it ¹.

The study showed that getting screened every few years reduced deaths from colon cancer and deaths from any cause, even though the total number of new cancer cases did not change ¹. This means that while cancer can still occur, catching it early through surveillance saves lives. The research did not find strong evidence that screening changed the stage of cancer at diagnosis, but the drop in mortality is a clear benefit ¹.

Other studies confirm that Lynch Syndrome involves mutations in specific genes like MSH2, MSH6, MLH1, and PMS2 ². Identifying these mutations helps doctors understand the specific risks for a patient and their family members ³. Because the risk is high but not absolute, doctors recommend enhanced screening plans for people who test positive for these gene changes.

What to ask your doctor

• What is my specific lifetime risk of developing colon cancer based on my genetic test results?
• How often should I have a colonoscopy to best manage my risk?
• Are there other cancers I should be screened for besides colon cancer?
• What lifestyle changes might help lower my overall cancer risk?