Appendix Table 2a.

Classification of serrated lesions^** for neoplastic potential in the screening-colonoscopy and HSgFOBT arm

Serrated Lesions
Histology	Size	Number of polyps	Location	Classification	Total Findings Per Participant in Screening-Colonoscopy Arm	Total Findings Per Participant in HSgFOBT Arm
HP (microvesicular or goblet cell)	<10 mm	Any number	Rectosigmoid	Hyperplastic	188	72
HP (microvesicular or goblet cell)	≤ 5 mm	≤ 3	Proximal to sigmoid	Hyperplastic	42	20
HP (microvesicular or goblet cell)	Any	≥ 4	Proximal to sigmoid	Non-advanced (neoplasia)	0	1
HP (microvesicular or goblet cell)	>5 mm	≤ 1	Proximal to sigmoid	Non-advanced (neoplasia)	5	4
SSL or TSA	< 10 mm	< 3	Any	Non-advanced (neoplasia)	39	21
SSL or TSA	< 10 mm	≥ 3	Any	Advanced (neoplasia)*	0	0
SSL or TSA	≥ 10 mm	1	Any	Advanced (neoplasia)*	14	6
HP (microvesicular or goblet cell)***	≥ 10 mm	Any	Rectosigmoid	Advanced (neoplasia)*	7	2
SSL	≥ 10 mm	≥ 2	Any	Advanced (neoplasia)*	3	1
SSL with dysplasia	Any	Any	Any	Advanced (neoplasia)*	2	2

High sensitivity fecal occult blood test (HSgFOBT), Hyperplastic polyps (HP), Sessile serrated lesion (SSL),Traditional serrated adenoma (TSA)

^*Advanced neoplasia classification includes colorectal cancer

^**Serrated lesions classifications were based on definitions from Rex and Gupta

^***HP (microvesicular or goblet cell) ≥ 10 mm in rectosigmoid (any number of polyps) were based on classification from Gupta¹