Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, is an autosomal-dominant inherited cancer susceptibility syndrome that affects approximately 1 in 35 patients diagnosed with colorectal or endometrial cancers, making it the most common inherited cancer syndrome.1 Lifetime risk of colorectal cancer for men and women with Lynch syndrome is 10% to 80%, and women with Lynch syndrome have a 15% to 60% lifetime risk of developing endometrial cancer.