Intestinal Cancer Risk in Crohn's Disease: A Meta-Analysis

To clarify the intestinal cancer risk in Crohn's disease (CD). 20 clinical studies (1965-2008) with a total of 40,547 patients with Crohn's disease-associated cancer (CDAC) were included in the meta-analysis (inverse variance weighted method). The incidence of CDAC in any CD patient was 0.8/1,000 person years duration (pyd) (CI, 0.6-1.0). The incidences of different carcinomas were: colorectal cancer 0.5/1,000 pyd (CI, 0.3-0.6), small bowel carcinoma 0.3/1,000 pyd (CI, 0.1-0.5), and cancers arising from CD-associated fistulae 0.2/1,000 pyd (CI, 0.0-0.4). Compared to the incidence in an age-matched standard population, the risk of colorectal cancer was increased by factor 2-3 and of small bowel cancer by factor 18.75, respectively. Mean patient age at diagnosis of CD-associated colorectal cancer was 51.5 years, thus 20 years earlier than in a standard population. The mean duration of CD until diagnosis of CDAC was 18.3 years. Duration of CD, age at diagnosis of CD, and anatomical area of CD involvement had no significant influence on cancer incidence. CD is a risk factor for colorectal cancer, small bowel cancer, and fistula cancer; however, compared to ulcerative colitis, cancer risk is moderate.