Lynch syndrome (LS) is a rare condition that runs in families. Conditions that run in families are known as familial or hereditary.
LS is also known as hereditary non-polyposis colorectal cancer (HNPCC). Because people with HNPCC have an increased risk of some other cancers, and not just colorectal cancer, health professionals usually call the condition Lynch syndrome, named after the doctor who discovered it.
Lynch syndrome is the most common cause of hereditary bowel cancer. However, fewer than 5 in 100 (5%) of all bowel cancers are linked to LS.
People with LS also have an increased risk of developing other cancers. In women, there is a higher risk of womb (endometrial) and ovarian cancers. Other cancers that can occur in people with LS include stomach, pancreas, small bowel, ureter and renal pelvis cancers.
Knowing about risk and having regular screening may help prevent some cancers. It may also help others to be found in the early stages, when they're more likely to be curable.