I am 43 year old male. My mother had Crohn's disease, so I have had a colonoscopy every 5 years since I was 35 (2 test, both negative). During my physical this year, my GP says he found blood in my stool during a Occult Stool Test. Thi sis the first time it has been positive, and I get tested every year. Should I be concerned about colon cancer?