IBD . This is a very complex topic, and you should discuss it at length with a gastroenterologist. There are too many variables and individual features to weigh. In most patients with moderate or severe disease, going without treatment is often very risky. Read up more on the crohn's and colitis foundation of america's website.
Cancer. Inflammatory bowel disease may refer to crohn's disease or ulcerative colitis. Ulcerative colitis is the one that classically has an increased risk for colon cancer. Treatment for ulcerative colitis is medical manangement. However, the risk of cancer starts to rise significantly after ten years with the disease, hence the recommendation for colectomy at that time.