What is the risk of colon cancer in inherited polyposis syndrome?

Inherited polyposis syndromes, such as familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary nonpolyposis colorectal cancer or HNPCC), are associated with a significantly increased risk of developing colon cancer. In the case of familial adenomatous polyposis, individuals with the condition often develop hundreds to thousands of adenomatous polyps during their teenage years or early adulthood, and if left untreated, nearly all of these individuals will develop colorectal cancer by the age of 40 to 50, leading to an estimated nearly 100% risk.

For Lynch syndrome, while the risk is slightly lower than that of FAP, it is still markedly increased, with an approximate lifetime risk of 40% to 80% for developing colorectal cancer among those affected.

Thus, in these inherited conditions, the almost certain progression from multiple polyps to cancer emphasizes the urgency of surveillance and preventative measures. Potential interventions, such as surgical options or regular screening, are typically recommended to manage this high risk effectively.