Similarity of colorectal cancer in Crohn's disease and ulcerative colitis: implications for carcinogenesis and prevention.

There is an increased risk of cancer in both ulcerative colitis and Crohn's disease. In 3121 patients with ulcerative colitis, 225 cases of cancer were diagnosed compared with 142.1 expected (standardized incidence ratio [SIR] 1.6, 95% CI 1.4 to 1.8), and in 1655 patients with Crohn's disease, 58 cases of cancer were detected compared with 47.1 expected (SIR 1.2, 95% CI 0.9 to 1.6). After excluding colorectal cancer the observed number of malignancies was very close to that expected for ulcerative colitis (SIR 1.0, 95% CI 0.9 to 1.2) and for Crohn's disease (SIR 1.1, 95% CI 0.8 to 1.5). Thus, the increased risk of cancer in inflammatory bowel disease is confined to colorectal cancer. In Crohn's disease 12 cases of colorectal cancer were observed (SIR 2.5, 95% CI 1.3 to 4.3). The increased risk was confined to those with colonic involvement and young age at diagnosis. In patients with colonic involvement and younger than age 30 years at diagnosis, the SIR was 20.9 (95% CI 6.8 to 48.7) versus 2.2 for those older than 30 years at diagnosis (95% CI 0.6 to 5.7). In ulcerative colitis 91 cases of colorectal cancer were observed with an SIR of 5.7 (95% CI 4.6 to 7.0). Extensive disease and young age at diagnosis were independent risk factors. Pancolitis at diagnosis resulted in an SIR of 14.8 (95% CI 11.4 to 18.9), 2.8 in left-sided colitis (95% CI 1.6 to 4.4) and 1.7 in proctitis (95% CI 0.8 to 3.2). There is great variation in the risk estimates in different studies worldwide. Different treatment strategies could be an explanation, a hypothesis that was substantiated in a study of 102 cases of colorectal cancer among patients with ulcerative colitis compared with 196 controls. Pharmacological therapy with sulfasalazine entailed a strong protective effect against colorectal cancer (relative risk of 0.34, 95% CI 0.190 to 0.62).

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Metagenomic Analysis of Common Intestinal Diseases Reveals Relationships among Microbial Signatures and Powers Multidisease Diagnostic Models

mSystems ◽

10.1128/msystems.00112-21 ◽

2021 ◽

Vol 6 (3) ◽

Author(s):

Puzi Jiang ◽

Sicheng Wu ◽

Qibin Luo ◽

Xing-ming Zhao ◽

Wei-Hua Chen

Keyword(s):

Colorectal Cancer ◽

Ulcerative Colitis ◽

Crohn’S Disease ◽

Crohn's Disease ◽

Phylogenetic Relationships ◽

Clinical Symptoms ◽

Data Sets ◽

Intestinal Diseases ◽

Gut Microbes ◽

Specific Cluster

ABSTRACT Common intestinal diseases such as Crohn’s disease (CD), ulcerative colitis (UC), and colorectal cancer (CRC) share clinical symptoms and altered gut microbes, necessitating cross-disease comparisons and the use of multidisease models. Here, we performed meta-analyses on 13 fecal metagenome data sets of the three diseases. We identified 87 species and 65 pathway markers that were consistently changed in multiple data sets of the same diseases. According to their overall trends, we grouped the disease-enriched marker species into disease-specific and disease-common clusters and revealed their distinct phylogenetic relationships; species in the CD-specific cluster were phylogenetically related, while those in the CRC-specific cluster were more distant. Strikingly, UC-specific species were phylogenetically closer to CRC, likely because UC patients have higher risk of CRC. Consistent with their phylogenetic relationships, marker species had similar within-cluster and different between-cluster metabolic preferences. A portion of marker species and pathways correlated with an indicator of leaky gut, suggesting a link between gut dysbiosis and human-derived contents. Marker species showed more coordinated changes and tighter inner-connections in cases than the controls, suggesting that the diseased gut may represent a stressed environment and pose stronger selection on gut microbes. With the marker species and pathways, we constructed four high-performance (including multidisease) models with an area under the receiver operating characteristic curve (AUROC) of 0.87 and true-positive rates up to 90%, and explained their putative clinical applications. We identified consistent microbial alterations in common intestinal diseases, revealed metabolic capacities and the relationships among marker bacteria in distinct states, and supported the feasibility of metagenome-derived multidisease diagnosis. IMPORTANCE Gut microbes have been identified as potential markers in distinguishing patients from controls in colorectal cancer, ulcerative colitis, and Crohn’s disease individually, whereas there lacks a systematic analysis to investigate the exclusive microbial shifts of these enteropathies with similar clinical symptoms. Our meta-analysis and cross-disease comparisons identified consistent microbial alterations in each enteropathy, revealed microbial ecosystems among marker bacteria in distinct states, and demonstrated the necessity and feasibility of metagenome-based multidisease classifications. To the best of our knowledge, this is the first study to construct multiclass models for these common intestinal diseases.

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