Lynch syndrome

Lynch syndrome is an inherited genetic condition that significantly increases the lifetime risk of several cancers, most notably colorectal and endometrial cancer, due to mutations affecting the body's DNA repair system. Understanding your specific gene mutation helps tailor a personalised, lifelong cancer surveillance programme.

It's caused by inherited mutations in one of several genes responsible for repairing errors that naturally occur in DNA (mismatch repair genes), most commonly MLH1, MSH2, MSH6 or PMS2. Inherited in an autosomal dominant pattern, each child of an affected parent has a 50% chance of inheriting the mutation.

Beyond colorectal and endometrial cancer, which carry the highest risk, Lynch syndrome also increases risk of ovarian, stomach, small bowel, urinary tract, and other less common cancers to varying degrees depending on the specific gene involved. This is why comprehensive, tailored surveillance covering multiple organ systems is recommended.

Yes, it carries a substantially increased lifetime cancer risk compared to the general population, but this risk can be significantly reduced through regular, proactive surveillance, and in some cases, risk-reducing surgery. Early detection through screening dramatically improves outcomes if cancer does develop.

Yes, it's a hereditary genetic condition, and genetic testing can confirm the diagnosis and identify at-risk family members who should also be offered testing and appropriate surveillance. Genetic counselling is an essential part of managing a Lynch syndrome diagnosis for the whole family.

There's no cure for the underlying genetic mutation, but a structured lifelong surveillance programme, particularly regular colonoscopy from a relatively young age, effectively catches and allows early treatment of any cancers that develop, significantly reducing cancer-related mortality. Risk-reducing surgery is also an option some individuals consider for certain cancer risks.

Management involves a personalised surveillance programme, typically including regular colonoscopy from a young age, gynaecological surveillance or risk-reducing surgery for women once childbearing is complete, and other specific screening based on the exact gene mutation identified. This is usually coordinated through a specialist clinical genetics and cancer screening service.

Colonoscopy is typically recommended every one to two years, starting significantly earlier than general population screening, often from the mid-twenties depending on the specific gene involved and family history. Your genetics team will provide a personalised surveillance schedule.

Both are inherited conditions significantly increasing colorectal cancer risk, but Lynch syndrome results from DNA mismatch repair gene mutations and typically involves fewer polyps that can progress to cancer more quickly, while familial adenomatous polyposis results from APC gene mutations causing hundreds to thousands of polyps and an even higher, near-certain cancer risk without treatment. Genetic testing distinguishes between these different inherited cancer syndromes, guiding appropriately tailored surveillance.

A family history of colorectal or endometrial cancer, particularly at younger ages or across multiple generations, should prompt clinical genetics referral. Private genetics consultations can typically be arranged within about two weeks, considerably faster than standard NHS waiting times.