Table 1. Clinical characteristics of patients and lesions.

	Pocket-creation method		Conventional method		P value
Number of lesions	73		53
Age, mean ± SD, years	68.9 ± 8.2		64.8 ± 10.8		0.02
Age ≥ 65 years, n (%)	50 (68)		30 (57)		0.19
Gender, male:female, n (%)	53 (73):20 (27)		40 (75):13 (25)		0.84
Tumor location, n (%)					0.83
Right colon	40 (55)		32 (60)
Left colon	25 (34)		16 (30)
Rectum	8 (11)		5 (9)
Macroscopic type, n (%)					0.04
Flat-elevated type	40 (55)		39 (74)
Pseudo-depressed type	33 (45)		14 (26)
Tumor diameter, median (IQR), mm	27 (21 – 32)		25 (20 – 33)		0.40
Tumor diameter ≥ 30 mm, n (%)	26 (36)		17 (32)		0.85
Expert endoscopist performed, n (%)	50 (68)		40 (75)		0.43
Prior biopsy, n (%)	31 (42)		16 (30)		0.19
Residual tumor, n (%)	2 (3)		1 (2)		1.00
Submucosal fibrosis, n (%)					0.38
F0 (none)	21 (29)		17 (32)
F1 (mild)	49 (67)		31 (58)
F2 (severe)	3 (4)		5 (9)
Hyaluronic acid solution injected, median (IQR), mL	39 (30 – 56)		34 (27 – 58)		0.32
Balloon assisted endoscopy used, n (%)	8 (11)		6 (11)		1.00
Pathological findings, n (%)					0.40
Adenoma	20 (27)	58 (79)	25 (47)	38 (72)
Intramucosal carcinoma	38 (52)		13 (25)
Slightly invasive ( < 1000 μm) submucosal carcinoma	11 (15)	15 (21)	10 (19)	15 (28)
Deeply invasive ( ≥ 1000 μm) submucosal carcinoma	4 (5)		5 (9)
En bloc resection, n (%, 95 %CI)	73 (100, 96 – 100)		49 (92, 82 – 98)		0.03
R0 resection, n (%, 95 %CI)	68 (93, 85 – 98)		48 (91, 79 – 97)		0.74
Bleeding, n (%, 95 %CI)	1 (1, 0 – 7)		2 (4, 1 – 13)		0.57
Perforation, n (%, 95 %CI)	0 (0, 0 – 4)		2 (4, 1 – 13)		0.18
Dissection speed, median (IQR), mm2/min	19 (13 – 24)		14 (10 – 22)		0.03

IQR, interquartile range; SD, standard deviation; CI, confidence interval.