Hereditary Non-Polyposis Colorectal Cancer (Lynch Syndrome): Understanding Your Family's Cancer Risk

This explainer details Lynch syndrome, which is the most common type of hereditary colorectal cancer, though it accounts for only about 3% of all colorectal cancer cases. It is a genetic condition that increases cancer risk. The root cause is a glitch in a "spell checker" gene within the mismatch repair (MMR) system, allowing genetic typos to accumulate and eventually leading to cancer. Current guidelines recommend universal screening (testing the tumor tissue) for everyone diagnosed with colorectal cancer to identify the faulty gene. Lynch syndrome carries the highest risk for colorectal cancer and the second highest risk for endometrial/uterine cancer in women. Management involves aggressive, proactive surveillance: colonoscopies start in the early 20s and are performed every 1 to 2 years, which can significantly improve life expectancy. Lynch-related cancers are often highly susceptible to modern immunotherapy drugs.