Inflammatory bowel diseases (Crohn's disease and ulcerative colitis) increase the risk of colon cancer: a recent meta-analysis reported an increased risk of developing colon cancer in people affected by Crohn's disease (relative risk: 2.59; 95% confidence interval 1.54–4.36). Another systematic review found a heavier relationship between ulcerative colitis and colorectal cancer: the risk exists for ulcerative colitis by decade of disease and is higher in pancolitis.