Carcinomas in inflammatory bowel disease: a narrative review on diagnostic imaging techniques

We aimed, therefore, to review the current evidence on imaging modalities and carcinomas overlapping IBD.

Patients affected by inflammatory bowel diseases (IBD) are at increased risk for developing both gastrointestinal and extra-intestinal cancers. The subtype of IBD, namely Crohn's disease or ulcerative colitis, the location, the activity, the extent, and the duration of the disease determine this risk. Standardized surveillance programs based on imaging techniques exist only for colorectal cancer, where colonoscopy is the milestone of early detection. Clarification is needed on whether different imaging modalities might be adopted in the algorithms for screening and diagnosis of cancers in IBD patients.

PubMed was searched up to July 2021 to identify relevant studies investigating the accuracy of imaging techniques in identifying carcinomas in IBD patients. The following text words and corresponding Medical Subject Heading/Entree terms were used: "imaging", "computed tomography", "magnetic resonance imaging", "inflammatory bowel disease", "adenocarcinoma" and "cancer".

Currently dye-chromoendoscopy (DCE) is established as the gold standard diagnostic modality for the detection of dysplasia in IBD, with a demonstrated superiority compared to white-light endoscopy. Two main radiological patterns have been described at cross-sectional imaging for both colorectal cancer and small bowel adenocarcinoma. The first subtype is characterized by a tissue mass, while the second subtype recognizes a circumferential thickening with or without the stricturing of the lumen. The diagnostic sensitivity, specificity, and accuracy of cross-sectional imaging techniques for the detection of carcinomas in the context of IBD are largely unknown and scarcely investigated. The definition of surveillance programs based on different imaging methods is warranted.