Inflammatory bowel disease–associated neoplasia

Abbreviations

Introduction

Chronic mucosal inflammation is a risk factor for the development of neoplasia in the gastrointestinal (GI) or extraintestinal organs. Inflammatory bowel disease (IBD) is a classic example. The natural history of colitis-associated neoplasia (CAN) in the majority of patients follows the sequence of chronic inflammation, low-grade dysplasia (LGD), high-grade dysplasia (HGD), and adenocarcinoma, which serves as a biological base for routine colonoscopy surveillance of long-standing ulcerative colitis (UC) or Crohn’s disease (CD) of the colon. However, some patients may skip the stage(s) in the tumorigenic sequence or have endoscopically ill-defined dysplastic lesions, making the surveillance challeningg. Endoscopic differentiation between chronic inflammation, inflammatory polyps, LGD, and HGD is difficult, resulting in the development of various image-enhanced endoscopy techniques. Chromoendoscopy and other image-enhanced endoscopies in the diagnosis, surveillance, and disease monitoring are discussed in a separate chapter ( Chapter 19 : Chromoendoscopy and advanced endoscopy imaging in inflammatory bowel disease).

Endoscopic features of IBD-associated colorectal cancer (CRC) have not been well described in the literature. Common endoscopic features of IBD-associated adenocarcinoma are mass-like lesions, strictures, and ulcerative lesions. However, some of those endoscopic features overlap with is seen in CD or UC. Endoscopic features of colitis-associated dysplasia are described in Chapter 19 , Chromoendoscopy and other advanced endoscopy imaging in inflammatory bowel disease.

The risk for neoplasia may persist in a minority of patients who undergo colectomy. Neoplasia can occur in the rectal cuff or pouch body in those with restorative proctocolectomy and ileal pouch–anal anastomosis (IPAA). The prognosis of IPAA-associated cancer is poor and surveillance endoscopy has been challenging due to the altered surgical anatomy and poorly defined disease course.

Patients with IBD can also develop squamous cell cancer (SCC) and non-Hodgkin’s lymphoma (NHL). There are currently no published surveillance guidelines for SCC or NHL. However, common endoscopic features of SCC and NHL are discussed in this chapter.

Colitis- or enteritis-associated adenocarcinoma

CRC is a common cause of mortality for Crohn's colitis or UC. Colonoscopy plays a key role in diagnosis, surveillance, and in selected patients, endoscopic therapy (such as endoscopic mucosal resection).