Background & aims: All patients diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) residing in Florence, Italy, in 1978-1992 were identified and included in a population-based study of cancer risk evaluation.
Methods: A total of 920 patients were followed up (median, 11 years), and 64 newly diagnosed malignancies were identified by linkage to the local cancer registry. Expected cases were calculated on the basis of age- and sex-specific cancer incidence rates to estimate relative risks in comparison with the general population.
Results: Overall, cancer incidence rates were not increased. A significant excess risk of Hodgkin's disease was observed among patients with UC (standardized incidence ratio, 9.3; 95% confidence interval [CI], 2.5-23.8). Respiratory tract cancers were significantly reduced to one fourth of the expected rate in patients with UC, but tended to be increased among patients with CD, who had a 50% higher risk of cancer at all sites. Only a nonsignificant, modestly increased risk of colorectal cancer was observed.
Conclusions: A strongly increased risk of Hodgkin's disease was evident in this first cancer follow-up of a representative series of patients with UC in a Mediterranean country. Two divergent risk patterns of respiratory tract cancers, possibly explained by differences in smoking habits, emerged in the 2 inflammatory bowel diseases.