P614. Incidences and characteristics of intestinal and extraintestinal cancers in patients with inflammatory bowel disease: a population-based study
The association between inflammatory bowel disease (IBD) and cancer is not well-defined. Our aim was to determinate the incidence and characteristics of intestinal and extraintestinal cancers among patients with IBD in our environment and to compare these with data in the background population.
Retrospective, multicenter, observational, 5-year follow-up (2007–2011), population-based study. Cumulative incidence and relative risk (RR) for the most common intestinal and extraintestinal cancers were calculated in the IBD cohort and compared with the local background population. Data corresponding to the baseline population were obtained using the tumour registry from the Community of Madrid. This registry contains all cases of cancer diagnosed in the 5-year follow-up period in the patients of each participating area. Demographic data, time from diagnosis of IBD to occurrence of cancer, and IBD treatment at time of cancer diagnosis were also collected in the IBD cohort.
Ten hospitals in Madrid contributed data for this study. 107 cancers were diagnosed in 96 of 7606 patients with IBD. Eleven patients (11.4%) were diagnosed with two or more different cancers. The cumulative incidence in the IBD group was 1.4% vs. 1.8% in local population; RR = 0.77; 95% CI: 0.11–5.05. At time of cancer diagnosis, the mean age in patients with IBD was 58±14 years, 57% males, 38% smokers, 24.5% were on treatment with thiopurines and 12.2% on anti-TNF drugs. The mean time course of IBD until cancer development was 120.2 months (IQR 36.0–179.5). Tumours were extraintestinal in 86.9% of patients with cancer. The most frequent neoplasms observed in the IBD cohort were skin, breast and colorectal tumours (Table 1). Compared with the background population, patients with IBD had a significantly increased RR of non-melanoma skin cancer and small bowel cancer. However, the risk of colorectal cancer was lower (P < 0.05) in patients with IBD (Table 1). These differences were similar in patients with Crohn's disease and ulcerative colitis. Only one case of non-Hodgkin lymphoma was observed in this series.
|*Significant differences (P < 0.05).|
The overall risk of cancer was not significantly increased among our patients with IBD. However, there was an increased risk of non-melanoma skin cancer and small bowel cancer. Although a higher RR of colorectal cancer has been described in patients with IBD, the magnitude of this risk was low in our series.