CANCER RISK IN COLITIS

CANCER RISK IN COLITIS

The risk of cancer in ulcerative colitis increases with duration of disease. At 10 years from diagnosis, it is approximately 1%, increasing to 10–15% at 20 years and 20% at 30 years. Patients with pancolitis (defined as the presence of inflammation prox - imal to the splenic flexure) of more than 10 years’ duration should be entered into endoscopic screening programmes in order to detect clinically silent dysplasia, which is predictiv e of increased cancer risk. The value of screening programmes remains somewhat controversial, as most patients with UC who develop cancer (approximately 3.5% of all patients) pres - ent between attendances for screening colonoscopy . Malignant change, often atypical and high grade, may be multifocal or subm ucosal ( Figure 75.4 ). Colonoscopic surveillance with dye spray (chromoendoscopy) or multiple biopsies every 10 /uni00A0 cm should look for subtle mucosal abnormalities, which can occur in flat mucosa or a DALM. Patients with UC and sclerosing cholangitis are also at a significantly greater risk of develop - ment of large bowel cancer.