This article reviews current society guidelines, highlighting similarities and differences, in an attempt to form a general consensus on

surveillance for patients with IBD, while drawing attention to controversial areas in need of further research. Most societies agree that all patients with a history of UC (even isolated proctitis) and Crohn’s colitis should be offered a screening colonoscopy approximately 8 to 10 years after the onset of clinical symptoms to re-stage extent of disease and evaluate for endoscopic features that confer a higher risk for IBD-associated Venetoclax clinical trial CRN (IBD-CRN). The exception is the NICE guideline,6 which recommends only offering colonoscopic surveillance to patients with Crohn’s colitis involving more than 1 segment of the colon or left-sided or more extensive UC, but not isolated ulcerative proctitis. All societies recommend that patients with PSC and UC should be enrolled in a surveillance program at the time of diagnosis. During the initial screening examination, restaging biopsies are recommended to determine disease extent and severity. The HDAC inhibitor extent of disease is defined by the maximum documented extent of disease on any colonoscopy. All societies recommend surveillance colonoscopy for UC patients with

left-sided or extensive colitis (thus excluding patients with isolated proctitis),1, 2, 3, 4, 5, 6 and 8 and for Crohn’s C59 chemical structure colitis involving more than 1 segment of the colon6 and 18 or at least one-third of the colon.2, 3, 5 and 8 The BSG considers patients with Crohn’s disease of less than 50% of colonic involvement, regardless of grade of inflammation, as lower risk, but does offer surveillance at the longest (5-year) intervals.1 The ACG guidelines recognize the possible increased risk of cancer in long-standing Crohn’s disease, but state that surveillance guidelines have yet to be defined, and do not endorse a screening or surveillance

strategy.19 All patients with UC and Crohn’s colitis should be offered a screening colonoscopy to restage the extent of disease and evaluate for endoscopic features that confer a higher risk for IBD-CRN. Current guidelines base screening for IBD-CRN primarily on duration of disease. The risk of IBD-CRN increases over time, although estimates of risk vary in the literature. Meta-analysis of older studies estimated an increase in risk over time, with a cumulative CRC risk of 2% at 10 years, 8% at 20 years, and 18% after 30 years of colitis.20 More recent population-based studies have demonstrated a lower overall risk, from 2.5% at 20 years, to 7.6% at 30 years, and 10.8% at 40 years of extensive UC.