The symptoms of colon cancer may include:

• Blood in the stools, turning feces a bright or dark red.
• Changes in normal bowel habits, such as diarrhea or constipation, when such changes happen with no apparent reason and last for more than three weeks.
• Unexplained weight loss.
• Abdominal pain.
• Feeling of not having emptied your bowels fully after having a movement.
• Unexplained fatigue.

Sometimes, cancer can cause a blockage (obstruction) in the intestine, provoking constipation and bloating, vomiting, and abdominal pain.