Symptoms and Complications
Polyps and colon cancer may cause slow, steady bleeding in the colon. The blood emerges with the stool but is often invisible. Many other conditions can cause blood in the stool, but if you experience it you should consult a doctor. Often, the blood loss isn't seen, but its effect is felt as iron-deficient anemia. Men and postmenopausal women with symptoms of anemia need a checkup.
Colon cancer can cause vague symptoms like weight loss or change in bowel habits, or it can cause no symptoms at all. More often, colon cancer has no symptoms until the disease is advanced. That's why screening is so vital.