Does ulcerative colitis cause colon cancer?
About 1 in 20 people (5%) with ulcerative colitis develop colon cancer. Having ulcerative colitis for a long time increases a person's chances of getting colon cancer.
Whether that will happen or not depends on how long the person has had the disease and how much of the colon is affected. The chance of developing cancer starts to increase after a person has had ulcerative colitis symptoms for 8 to 10 years. So, doctors often recommend that people who have had ulcerative colitis for 8 years or more have an exam every year or 2 that shows whether cancer has started to grow. The exam is called a colonoscopy.
During a colonoscopy, the doctor removes tiny pieces of the inside wall (lining) of the colon. The pieces are examined under a microscope for signs of cancer.
One of the first signs of cancer is that cells are growing too fast or are not the normal size or shape. A collection of such cells is called dysplasia. Although dysplastic cells are not cancer, they warn that the risk of developing colon cancer is high. When there is a lot of dysplasia, the entire colon may have to be removed.
Recent research shows that taking a medication containing 5-aminosalicylic acid (abbreviated 5-ASA) may reduce the chances of developing colon cancer for some patients. Doctors are doing more research to find out how it may help prevent cancer and which patients may be helped the most.