Table 1.

Key elements in screening patients with long-standing, extensive colitis, adapted from the AGA and BSG guidelines

	Key element
Surveillance colonoscopy	Colonoscopy with systematic biopsies
	Perform surveillance every 1 to 2 yr
	After 8 to 10 yr of disease in those with pancolitis
	After 15 yr of disease in those with left-sided colitis
Biopsy protocol	Biopsies every 10 cm in all 4 quadrants.
	Additional biopsies of strictures and mass lesions other than pseudopolyps
	Polyps that appear potentially dysplastic remove by polypectomy with biopsy of adjacent flat mucosa
Dysplasia	If HGD or multifocal low-grade dysplasia is found in flat mucosa refer for colectomy
	Presence of low-grade dysplasia, particularly if it is unifocal: no consensus
	DALM is an indication for colectomy
Other factors of consideration to advise on colectomy	Ongoing colitis-related symptoms
	Life expectancy
	Duration, severity and extent of colitis
	A personal history of primary sclerosing cholangitis
	A family history of colorectal cancer
	Discussion around the time of surveillance of benefit, harms, and short comings of colonoscopy surveillance