i had a colonoscopy 2 years ago. everything was clean. i have diverticulitis and internal hemorroids. my doctor had me do an occult stool test 3 weeks ago. it came back 2positives and 1 negative. i went to my gastroenterolist and did another 1 sample that came back positive. he wants to do another colonoscopy. is it possible that i have developed colon cancer in that short a time?