It depends. Where the lesion is located not to speak sometimes there are no localizing symptoms and the disease is caught when it is spread. Rectal bleeding is suspicious, constipation, intestinal obstruction (rectum and left colon), unexplained anemia (right colon) lose stools ( right colon) abdominal pain of course. Periodic colonoscopy to catch polyps for prevention . Also a baby Aspirin a day, good too.
None to extreme in.. Like any life events displaying themselves on their own pattern of full spectrum ranging from none to extreme, the symptoms of colon cancer may range from nothing but occult blood in stool at the its very early stage to gross blood in stool or/and bowel obstruction, weight loss, general weakness and ... at its end. More? Peruse the lists on Facts of Life - 1, 2, & 3 in www,Formefirst.com.