Colon cancer is a serious disease that occurs when cancerous cells originate in the tissues of the colon. As with most cancer, there are usually no early signs of the disease. When symptoms of colon cancer do appear, they can include bowel problems such as blood in the stool, narrow stools, and diarrhea or constipation. Because other conditions may cause the same symptoms, it is important to see your healthcare provider if you experience any of these symptoms. Some tests used to diagnose the cancer include digital rectal exams, fecal occult blood tests (FOBT), and colonoscopies. A few treatment options include surgery, chemotherapy, radiation therapy, and a combination of treatments. Among the risk factors for colon cancer are a history of ulcerative colitis (ulcers in the lining of the large intestine) or Crohn's disease and a family history of colon or rectal cancer.