Cancer risk higher with Crohn’s disease, not ulcerative colitis

Patients with Crohn’s disease were at increased overall risk for cancer compared with the general population, while those with ulcerative colitis were not in a recent study.

Researchers evaluated 1,437 patients with ulcerative colitis (UC) and 774 with Crohn’s disease (CD) between 1978 and 2002 in Denmark. Follow-up was conducted until Dec. 31, 2010 or cancer incidence, death or emigration during a median of 15 years and 14 years for the UC and CD groups, respectively.

Cancer developed in 207 patients in the UC group, with no significant increase in overall risk (standardized IR=1.12; 95% CI, 0.97-1.28) regardless of sex, age, tobacco use, disease localization or use of 5-aminosalicylic acid (5-ASA) or thiopurines. These patients, however, were at significantly elevated risk for prostate cancer (SIR=1.82; 95% CI, 1.17-2.71), particularly among patients who had ever used 5-ASA (SIR=1.84; 95% CI, 1.16-2.76) and had never used thiopurines (SIR=1.84; 95% CI, 1.17-2.76).

Patients with CD were at significantly increased overall cancer risk, with 129 cases developing during follow-up (SIR=1.55; 95% CI, 1.29-1.84). Specifically, these patients were at elevated risk for small bowel (SIR=15.18; 95% CI, 1.84-54.78) and lung cancers (SIR=2.13; 95% CI, 1.19-3.52), and cervical dysplasia (SIR=1.65; 95% CI, 1.1-2.37) and non-Hodgkin’s lymphoma (SIR=3.43; 95% CI, 1.38-7.07). Men with CD also were significantly more likely to develop colorectal cancer (SIR=2.43; 95% CI, 1.05-4.78).

The increased lung cancer risk in CD patients was associated with smoking and more prominent among women; cervical dysplasia was linked to smoking, 5-ASA use, thiopurine exposure and younger age at diagnosis. Lymphoma diagnosis in CD patients was associated with nonuse of 5-ASA, younger age and small bowel and colonic disease.

“This population-based cohort study … showed that the overall risk of cancer was increased in CD patients, but not in UC patients,” the researchers wrote. “However, the risk of certain subtypes of cancer was significantly higher than in the general population. … Our study’s findings add to the ongoing discussion of ways of differentiating between baseline and treatment-induced cancer risk in IBD patients.”

Disclosure: The researchers report no relevant financial disclosures.