i am now 35 years old. i am suffering from blooding stool since when i was 20 years old. blood comes out after bowel movement and i fill no pain. blood comes out in drops in huge quantities. i went to many good doctors but they said me that i have no piles even i have done colonoscopy but report is that i have no piles or phisher. so is it cancer? if it can it remain inactive form 15 years??