I don't know your age but as we get older, polyps become more common. I never had any in my previous scopes, then just this past May two were removed. One was rather large and had developed in 3.5 years. Once a person develops polyps, more will usually follow. That is why people are encouraged to get periodic scopes.
Did you question your GI as to why he did not remove the polyp when he found it? You might get an better understanding about
polyps by reading this:Colon Polyps by MedicineNet.com