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, among other things, a change in bowel habits; blood (either bright red or very dark) in the stool; and frequent gas pains, bloating, fullness, or cramps. 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 sigmoidoscopies, digital rectal exams, and fecal occult blood tests (FOBT). There are many treatment options available to people with colon cancer, including chemotherapy, surgery, and radiation therapy. People 50 years old or older have an increased risk of developing colon cancer.