Colorectal cancer in inflammatory bowel diseases: a population-based study (1976-2008)

Few data are available on the incidence, characteristics, treatment, and prognosis of inflammatory bowel disease (IBD)-associated colorectal cancer (CRC) in population-based cohorts.

Among the 19,451 new cases of CRC recorded in the Burgundy digestive cancer registry between 1976 and 2008, all cases of IBD-associated CRC were identified. Incidence rates were age-standardized according to the world standard population. Prognosis was determined using univariate and multivariate relative survival.

Thirty-eight IBD-associated CRC were identified (ulcerative colitis, n = 29; Crohn's disease, n = 9). The mean age at CRC diagnosis was greater for patients without IBD than those with IBD (70.9 vs. 56.9 years, respectively; P < 0.001). Distributions of gender, stage at presentation, location, and histological type of CRC did not differ from those of sporadic cases. The overall world age-standardized incidence of IBD-associated CRC per 100,000 was 0.11 (standard deviation [SD]: 0.03) for men and 0.06 (SD: 0.02) for women. Only age was independently associated with IBD-associated CRC (odds ratio [OR]: 0.22; 95% confidence interval [CI]: 0.12-0.43; P < 0.001). Treatment modalities did not differ between IBD and non-IBD patients. Five-year relative survival was 51.9% (95% CI: 51.1-52.8%) in non-IBD patients and 41.3% (95% CI: 24.6-57.2%) in IBD patients (P = 0.201). After adjustment for age, gender, and stage at diagnosis, the excess hazard of death was 1.46 times higher in IBD than in non-IBD patients (95% CI: 0.94-2.27; P = 0.070).

Apart from age, the characteristics of IBD-associated CRC were similar to those of non-IBD CRC. The prognosis of CRC may be poorer in patients with IBD than in those without IBD.