Stage at diagnosis and survival of colorectal cancer with or without underlying inflammatory bowel disease: a population-based study.

BACKGROUND Inflammatory Bowel Disease(IBD) is a risk factor for colorectal cancer(CRC). The aim of this study is to determine whether stage at diagnosis and survival differ between sporadic, ulcerative colitis (UC) and Crohn's disease(CD) related CRC. METHOD The English National Cancer Registry (NCIN), Hospital Episode Statistics(HES) and Office for National Statistics(ONS) datasets between 2000-2010 were linked, providing data on co-morbidities, stage and date of death. A logistic regression model determined whether IBD was associated with an early(I/II) or late (III/IV)cancer. Cox regression analysis was used to examine survival differences between sporadic, UC and CD. RESULTS A total of 234009 patients with CRC were included, of which 985(0.4%) and 1,922(0.8%) had CD and UC respectively. UC, but not CD, was associated with an earlier stage compared with sporadic cancers (OR 0.88 CI 0.79-0.98 p=0.02). CD had a significantly worse survival compared with sporadic patients for stage II(HR=1.71, CI 1.26-2.31 p<0.005) and III(1.53, CI 1.20-1.96 p<0.005) cancer. UC patients were associated with worse survival compared with the sporadic group for both stage III(1.38, CI 1.17-1.63 p<0.0005)and IV(1.13, CI 1.01-1.28 p=0.04)cancer. After excluding sporadic patients, UC was associated with improved survival compared with CD(0.62, CI 0.43-0.90 p=0.01) for stage II cancer. CONCLUSION Patients with IBD are diagnosed at an earlier stage but tend to have a worse survival compared with sporadic cases of CRC, in particular for nodal disease(stage III).Specifically, patients with CD related CRC appear to fare worst in terms of survival compared with both the sporadic and UC group.