Underwater vs conventional endoscopic mucosal resection for nonpedunculated colorectal neoplasms: A randomized controlled trial

Table 2 Endoscopic and pathological characteristics of the colorectal lesions, n (%)

Characteristics	Total (n = 260)	CEMR (n = 130)	UEMR (n = 130)	P value
Location of lesion
Rectum	67 (25.8)	28 (21.5)	39 (30.0)	0.119
Sigmoid colon	98 (37.7)	52 (40.0)	46 (35.4)	0.443
Descending colon	16 (6.2)	10 (7.7)	6 (4.6)	0.302
Transverse colon	34 (12.3)	17 (13.1)	17 (13.1)	1
Ascending colon	36 (13.8)	18 (13.8)	18 (13.8)	1
Cecum	9 (3.5)	5 (3.8)	4 (3.1)	11
Size, median (minimum-maximum) (mm)	20 (10-30)	12 (10-30)	12 (10-25)	0.7582
10-19	233 (89.6)	117 (90.0)	116 (89.2)	0.839
20-30	27 (10.4)	13 (10.0)	14 (10.8)
Paris classification				0.600
0-Is	172 (66.1)	88 (67.7)	84 (64.6)
0-IIa/0-IIb	88 (33.9)	42 (32.3)	46 (35.4)
NICE classification				0.656
Type 1	22 (8.5)	10 (7.7)	12 (9.2)
Type 2	238 (91.5)	120 (92.3)	118 (90.8)
WHO classification
Nonneoplastic polyp	14 (5.4)	6 (4.6)	8 (6.2)	0.583
Tubular adenoma	161 (61.9)	76 (58.5)	85 (65.4)	0.250
Tubulo-villous adenoma	36 (13.8)	21 (16.2)	15 (11.5)	0.281
Serrated lesion	49 (18.8)	27 (20.8)	22 (16.9)	0.428
Vienna classification
No dysplasia	21 (8.1)	9 (6.9)	12 (9.2)	0.495
Low-grade dysplasia	209 (80.4)	108 (83.1)	101 (77.7)	0.274
High-grade dysplasia	26 (10.0)	10 (7.7)	16 (12.3)	0.215
Superficial cancer	4 (1.5)	3 (2.3)	1 (0.8)	0.6221

¹P values were computed with Fisher’s exact test.

²P values were computed with the Mann-Whitney U test.

CEMR: Conventional endoscopic mucosal resection; NICE: Narrow band imaging international colorectal endoscopic classification; UEMR: Underwater endoscopic mucosal resection; WHO: World Health Organization.