Lynch syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC), is due to mutations in the mismatch repair (MMR) genes.
An estimated 800,000 people in the United States have Lynch syndrome. Individuals with Lynch syndrome are more likely to get colorectal, uterine (endometrial), ovarian, stomach, small bowel, hepatobiliary tract (liver, pancreas, gallbladder), urinary tract (kidney, bladder, ureters), brain, and skin cancers. About 3% of colorectal cancers and 2% to 5% of uterine (endometrial) cancers are due to Lynch syndrome.1
The absolute cancer risks for individuals with Lynch syndrome are1—
- Colorectal cancer: 25% to 82% (in other words, between 25% and 82% of those with Lynch syndrome may develop colorectal cancer).
- Uterine (endometrial) cancer: 20% to 60%.
- Ovarian cancer: 9% to 12%.
- Stomach cancer: 11% to 19%.
- Hepatobiliary tract cancer: 2% to 7%.
- Urinary tract cancer: 4% to 5%.
- Small bowel cancer: 1% to 4%.
- Brain and central nervous system cancer: 1% to 3%.
1National Comprehensive Cancer Network. NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal [PDF-913KB] Note: Login required to access.