Lynch Syndrome: — Cancer Risks, Screening and Treatment

No. Lynch syndrome raises your lifetime risk significantly, but a proportion of carriers never develop cancer, particularly those who follow a regular surveillance programme. The screening schedule exists to catch any change early, when it is most treatable, and that is a very different position from having no warning. Knowing your status gives you and your medical team the ability to act before something becomes serious, which is the point of genetic testing in this context.

The chance is roughly one in two, regardless of sex. Lynch syndrome follows an inheritance pattern where one changed copy of the gene — from either parent — is enough to raise cancer risk, and that changed copy passes to each child with equal probability. The only way to know for certain whether you inherited the variant is targeted genetic testing for the specific change known in your family. This is simpler and often less expensive than full panel testing because the family variant has already been identified.

Yes. Germline genetic testing for Lynch syndrome is available at major cancer centres and through specialist genetic testing laboratories in India. Tumour testing for MSI status and mismatch repair protein expression by immunohistochemistry is also available and is often done first on a cancer sample before germline testing is arranged. Your oncologist can advise on which test applies to your situation. Costs are indicative and vary between centres, so ask directly for the current figure at the place you are being treated.

MSI-high — microsatellite instability high — describes a pattern in tumour DNA that results from a mismatch repair gene not working, which is exactly what Lynch syndrome causes. NCCN and ESMO recognise MSI-high status as a predictor of response to checkpoint inhibitor immunotherapy in several cancer settings. If you develop cancer and the tumour is tested, an MSI-high result is directly relevant to treatment decisions. Your oncologist should know your Lynch syndrome status from the beginning so this information is factored in when planning treatment.

Yes. People who have had one Lynch syndrome-related cancer have an elevated risk of a second, separate cancer. Follow-up surveillance after treatment is more intensive and continues for life rather than tapering off after five years. Surgeons should also be aware of your Lynch syndrome status when planning an operation, because more extensive surgery at the time of the first cancer can sometimes reduce the risk of a second one. Make sure every specialist involved in your care knows about your Lynch syndrome diagnosis.

The genetic test report should specify the gene — MLH1, MSH2, MSH6, PMS2, or EPCAM — and the precise change found. If you have only been told that Lynch syndrome runs in the family without a written report, ask your oncologist or the testing centre for the full result in writing. The specific gene matters because it affects which cancers are most elevated and which surveillance is most important. A clinical geneticist can explain the specific implications of your family's variant in detail.