Table 4. Comparison of Polyp Characteristics between High-Risk Polyps Detected by Initial Colonoscopy and Those Detected by Surveillance Colonoscopy.

	First high-risk polyp	Second high-risk polyp	p value
n	434	51
Size (max), mm	14.5±9.1	11.8±7.2	0.015
Site
Left (DC-R)	255 (58.8%)	23 (45.1%)	0.055
Right (C-SF)	176 (40.6%)	28 (54.9%)
Polyp number
Total number	3.7±3.2	3.1±1.9	0.05
1-2	186 (42.9%)	20 (39.2%)	0.451
3-9	225 (51.8%)	30 (58.8%)
≥10	23 (5.3%)	1 (2.0%)
Number of polyps >1 cm	1.0±1.1	0.7±0.5	0.031
Pathology
Adenoma	187 (43.1%)	38 (74.5%)	<0.001
Villous	83 (19.1%)	2 (3.9%)
High-grade	164 (37.8%)	11 (21.6%)

DC, descending colon; R, rectum; C, cecum; SF, splenic flexure.