Lynch syndrome is a genetic condition that increases your risk of developing cancer, often before age 50. Though it’s most associated with colorectal cancer, it can cause many different types of cancer, including endometrial cancer (EC).
Understanding Lynch syndrome
Formerly called hereditary nonpolyposis colorectal cancer (HNPCC), Lynch syndrome is an inherited disorder caused by mutations in one of several DNA mismatch repair (MMR) genes, including MLH1, MSH2, MSH6, PMS2 and EPCAM.
These genes are responsible for correcting errors that occur during DNA replication. When they are mutated, damaged cells can build up in the tissue, thus increasing the risk of cancer.
Lynch syndrome is most commonly associated with colon cancer. In fact, HNPCC is now used to describe a genetic predisposition to colon cancer.
But Lynch syndrome is also the most common inherited cause of endometrial cancer. Women with Lynch syndrome have up to a 60% lifetime risk of developing endometrial cancer, often at a younger age than the general population.
Lynch syndrome also increases the risk of developing ovarian, gastric, brain, prostate, liver, gallbladder and pancreatic cancers.
Screening for Lynch syndrome
Lynch syndrome itself doesn’t cause symptoms; its only impact is in the development of cancer cells. In many women, EC symptoms may be the first sign of Lynch syndrome.
For this reason, screening for Lynch syndrome is often recommended for women diagnosed with EC under the age of 50, particularly if they have a personal or family history of other Lynch-associated cancers.
Screening involves testing a sample of the cancer cells with one of the following methods:
- Immunohistochemistry (IHC), which checks for the presence of MMR proteins in tumor tissue.
- Microsatellite instability (MSI) testing, which looks for genetic errors or instability in the tumor’s DNA.
If these screenings are abnormal, genetic testing can confirm a Lynch syndrome diagnosis. This typically involves giving a blood sample.
A diagnosis of Lynch syndrome has important implications for both you and your family. If you have the condition, your first-degree relatives (parents, siblings and children) have a 50% chance of having the same mutation.
Learn more about EC testing and diagnosis
Mitigating risks
Early identification of Lynch syndrome can help you and your family members take steps to reduce the risk of cancer.
For women who have Lynch syndrome, proactive risk management can include:
- Increased surveillance: Annual or biennial (once every two years) endometrial sampling and transvaginal ultrasound starting between the ages of 30 and 35 might be recommended, to catch EC in earlier stages if it develops.
- Risk-reducing surgery: Some women may opt for a preventive hysterectomy (removal of the uterus) and oophorectomy (removal of both ovaries) to reduce their cancer risk.
To monitor for colorectal cancer, your doctor may also recommend starting colonoscopy screenings at an earlier age, and they might be done more frequently.
If you have Lynch syndrome, your doctor can discuss other preventive strategies to reduce your risk of cancer.
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