Bloody stools
This is one of the signs that alert people to go to the doctor before they discover a malignant tumor lying in the colon mucosa. Bloody stools is a common sign and symptom of cancer, but there are many other causes a doctor should address. When this hemorrhage is composed of red blood recently spilled on the intestinal lumen, it means the tumor or problem causing the intestinal bleeding is near the anal opening (in the descending colon or sigmoid).