Interval colorectal cancers in inflammatory bowel disease: the grim statistics and true stories

Abstract

Interval colorectal cancers (CRCs) may account for approximately one half of all CRCs identified during IBD surveillance. The etiology of interval CRCs is multifactorial, with procedural factors likely to play a major role. Molecular events promoted by inflamed mucosa may augment the cancer risk and perhaps explain some interval CRCs. This article reviews key studies relating to CRC risk in the patient with IBD, paying particular attention to the occurrence of interval CRCs. The most common factors implicated in the etiology of interval CRCs, in particular missed, incompletely resected lesions, the adherence to recommended surveillance intervals and biologic pathways associated with a faster progression to cancer are examined. Basic concepts for quality and effectiveness of colonoscopic surveillance in IBD are summarized.

Keywords: Colonoscopy; Colorectal cancer; Crohn's disease; Inflammatory bowel disease; Interval colorectal cancer; Surveillance; Ulcerative colitis.