What are my chances of getting colon cancer in my 20s, 30s and 40s?

The average risk of getting colon cancer when you're younger is still low but rising. In the early 2000s, about 5% to 7% of colon cancer diagnoses were considered early onset. Now, around 10% of colon cancer diagnoses happen in people younger than 50. Most of these diagnoses happen between the ages of 40 and 49. 

Here's the risk of being diagnosed with colon cancer by decade: 

• 20s: About 2.3 people in 100,000.
• 30s: About 6.4 people in 100,000.
• 40s: About 19.2 people in 100,000.

Keep in mind that having a first-degree relative with colon cancer increases your risk by more than four times. A first-degree relative is a parent, sibling or child. Some inherited conditions, such as  Lynch syndrome or familial adenomatous polyposis (FAP), can dramatically increase your lifetime risk of colorectal cancer. For people with Lynch syndrome, the risk can be as high as 80%, and for those with FAP, the risk can approach 100% without preventive surgery.