What happens if they find a growth in my colon or rectum?

The point of looking. The whole point of undergoing a colon evaluation is to identify who is at risk for colon cancer, & to remove lesions before they grow larger. Most polyps are not pre-cancerous, but it is not always possible to tell on visual inspection alone. Identified polyps are removed at the time of your colonoscopy exam. Larger lesions are biopsied to determine if surgery is indicated. Get your colonoscopy!