What is colon cancer? Colon cancer is cancer of the colon or large intestine. Rectal cancer is cancer of the last few centimeters of the colon. Together, they are often called colorectal cancers. Most cases of colon cancer begin as small, harmless clumps of cells called polyps. Over time, some of these abnormal growths can become colon cancers. Polyps may be small and produce few signs of disease. For this reason, doctors recommend regular screening tests to help prevent colon cancer. Symptoms Some symptoms of colon cancer are: change in bowel habits, including diarrhea or constipation, rectal bleeding or blood in the stool, constant abdominal discomfort, such as cramps, gas, or pain, feeling like the bowels are not emptying completely, weakness or tiredness and/or unexplained weight loss. Many people with colon cancer have no signs of disease in the early stages of the disease. When signs of the disease appear, they will likely differ depending on the size of the cancer and location in the large intestine. If you notice any of these signs of colon cancer, such as blood in your stool, make an appointment with your doctor. Talk to your doctor about when you should start screening for colon cancer. Guidelines generally recommend that colon cancer screenings begin at age 50. Many doctors recommend more frequent or early screening if you have other risk factors, such as a family history of the disease. Causes In most cases, it is not clear what causes colon cancer. Doctors know that colon cancer occurs when healthy cells in the colon undergo a change. Healthy cells grow and divide in order to keep the body functioning properly. But when a cell is damaged and becomes cancerous, the cells continue to divide, even when there are no new cells... middle of paper... fostering is a routine component of rectal cancer treatment, particularly if The cancer has passed through the wall of the rectum or has reached nearby lymph nodes. Radiotherapy, usually combined with chemotherapy, may be used after surgery to reduce the risk that the cancer may return to the rectum where it originated. Prevention To prevent the spread of new cancers, scientists examine risk factors and protective agents. Anything that increases your chance of getting cancer is called a cancer risk factor; anything that reduces your chance of getting cancer is called a cancer protective factor. Some cancer risk factors can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular excise taxes and a healthy diet can help reduce the chances, but they are not promised.