Colorectal Cancer in Inflammatory Bowel Disease: Epidemiology, Pathogenesis and Surveillance

Abstract

Background: Inflammatory bowel disease (IBD; including ulcerative colitis and Crohn's disease) is associated with an increased risk for colorectal cancer (CRC). Chronic mucosal inflammation is a key factor in the onset of carcinogenesis in IBD patients. Although most gene alterations that cause sporadic CRCs also occur in patients with IBD-associated CRC, some gene sequences and mutation frequencies differ between sporadic CRCs and IBD-associated CRCs. Summary: This review explores the incidence of CRC in IBD patients, with the goal of identifying the risk and protective factors for CRC in order to facilitate dysplasia management via individualized surveillance strategies. Key Message: The incidence of CRC is higher among IBD patients. Identifying the risk and protective factors for CRC will facilitate dysplasia management via individualized surveillance strategies. Practical Implications: Several risk factors, including active inflammation, the coexistence of primary sclerosing cholangitis, a family history of sporadic CRC and the extent and duration of colonic disease, can lead to the development of CRC in patients with IBD. These risk factors should be utilized in individualized surveillance strategies to lower CRC incidence among IBD patients. Use of 5-aminosalicylic acid may play an important role in CRC prevention. Until newer, more reliable markers of IBD-associated CRC risk are found, dysplasia will continue to be the best marker of CRC risk in IBD. Dysplasia management continues to play a key role in preventing the progression of carcinogenesis.

Genomic characterization of colitis-associated colorectal cancer

“…IBD is associated with an increased risk of CRC in which the carcinogenesis of CAC depends on unique environmental, genetic, and immunologic factors compared with sporadic CRC [ 41 ]. Although genomic sequencing for patients with IBD using NGS technology has not been thoroughly investigated, recent studies regarding CAC have suggested that there are several mutational differences between patients with sporadic CRC and those with CAC.…”

Interobserver Agreement in the Diagnosis of Inflammatory Bowel Disease-Associated Neoplasia in China in Comparison to Subspecialized American Gastrointestinal Pathologists

“…In two recent meta-analyses, the overall incidence rate of CAC among 181,923 and 54,478 UC patients was 1.58 to 3 per 1000 patient years, respectively [ 20 , 21 ]. Although randomized trials to show the effectiveness of surveillance programs in reducing IBD-associated mortality are lacking, many retrospective case series studies have revealed a benefit for surveillance in patients with IBD [ 12 , 22 ]. For IBD patients entering a surveillance program, the standard of care includes periodic colonoscopic exams with protocol biopsies (4 quadrant biopsies every 10 cm) and targeted biopsies if a lesion is seen to detect dysplasia [ 5 ].…”

The Achievements and Challenges of Mesenchymal Stem Cell-Based Therapy in Inflammatory Bowel Disease and Its Associated Colorectal Cancer

“…Chronic mucosal inflammatory damage is one of the key factors linked with the inception of carcinogenesis in an IBD patient. Even though several genetic alterations that result in sporadic CRCs also take place in patients with IBD-associated CRC, certain gene sequences as well as mutation frequencies differ between IBD-associated CRCs and sporadic CRCs [50]. Several other risk factors ranging from genetics [51], environmental, lifestyle, and intrinsic gut factors [52] also contribute to CRC occurrence in individuals having IBDs.…”