Survival of Colorectal Cancer in Patients With or Without Inflammatory Bowel Disease: A Meta-Analysis

Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal cancer (CRC), but little is known about the influence of IBD on CRC prognosis. The aim of this study was to perform a meta-analysis to compare survival in CRC patients with IBD (IBD-CRC) and without IBD. An electronic search was conducted via PubMed, Embase, and the Cochrane Library to identify eligible trials until July 2015. We pooled the hazard ratios (HRs) and their 95 % confidence intervals (CIs) to quantitatively assess the survival of CRC in patients with or without IBD. In addition, clinicopathological parameters of IBD-CRC versus non-IBD CRC were evaluated. Twelve studies containing a total of 3472 IBD-CRC patients were eligible according to our selection criteria. Our analysis indicated that CRC patients with IBD had shorter overall survival than those without IBD (HR 1.24, 95 % CI 1.19-1.29). IBD-CRC showed a propensity to develop in proximal colon [odds ratio (OR) 2.52, 95 % CI 1.35-4.72] and correlated with worse differentiation of tumor (OR 1.59, 95 % CI 1.26-1.99) compared to non-IBD CRC. Meta-regression analysis showed that sample size (P = 0.002) could explain 99.01 % inter-study heterogeneity. This meta-analysis found poorer overall survival in CRC patients with IBD than CRC patients without IBD, and further prospective research to confirm these findings is warranted.