LAUSR

OBJECTIVE The aim of our study was to conduct a systematic review and meta-analysis comparing the survival outcomes of IBD-associated and non-IBD-associated CRC. SUMMARY BACKGROUND DATA Investigations comparing the prognosis in colorectal cancer (CRC) patients with and without inflammatory bowel disease (IBD) have yielded conflicting results. METHODS PubMed/MEDLINE, Embase, Web of Science, Cochrane Library were searched for studies evaluating the prognostic outcomes between CRC patients with IBD and those without IBD. Estimates of survival-related outcomes and clinicopathological features in IBD-CRC and non-IBD CRC were pooled through random-effects or fix-effects models. The study is registered with PROSPERO, CRD42021261513. RESULTS Of 12,768 records identified, twenty-five studies with 8,034 IBD-CRC and 810,526 non-IBD CRC patients were included in the analysis. IBD-CRC patients have a significant worse overall survival (OS) with the hazard ratio (HR) of 1·33 (95% CI: 1·20-1·47) than those without IBD. Pooled estimates of cancer-specific survival demonstrated that IBD-CRC patients had a poorer cancer-specific survival than those without IBD with fixed-effect model (HR, 2·17; 95% CI: 1·68-2·78; P < 0·0001). Moreover, ulcerative colitis-associated CRC patients have favorable OS than Crohn's disease-associated CRC (HR 0·79, 95% CI: 0·72-0·87). Compared to non-IBD-CRC, patients with IBD-associated CRC are characterized by an increased rate of poor differentiation (OR 2·02, 95% CI: 1·57-2·61), mucinous or signet ring cell carcinoma (OR 2·43, 95% CI: 1·34-4·42), synchronous tumors (OR 3·18, 95% CI: 2·26-4·47), right-sided colorectal cancer (OR 1·62, 95%CI: 1·05-2·05), male patients (OR 1·10, 95% CI: 1·05-1·16), and a reduced rate of R0 resections (OR 0·60, 95% CI: 0·44-0·82). CONCLUSIONS IBD-CRC patients have a significant worse OS than patients with non-IBD CRC, which may be attributed to more aggressive histological characteristics and a lower rate of R0 resections at the primary tumor site. Optimized therapeutic standards and tailored follow-up strategies might improve the prognosis of IBD-CRC patients.