Table 3.

Factors associated with sufficient safety margin after endoscopic submucosal dissection (Univariate)

	Safety margin ≤ 1 mm	Safety margin > 1 mm	P value
	n = 63	n = 352
Age, yr (mean ± SD)	65.9 ± 11.1	63.9 ± 9.5	0.14
Male/female	38/25	253/99	0.12
Tumor margin, n (%)			0.52
Well-defined	53 (84.1)	284 (80.7)
Ill-defined	10 (15.9)	68 (19.3)
Tumor size, n (%)			0.55
≤ 20 mm	21 (33.3)	95 (27.0)
21-30 mm	12 (19.0)	65 (18.5)
31-40 mm	14 (22.2)	108 (30.7)
> 40 mm	16 (25.4)	84 (23.9)
Tumor location, n (%)			< 0.0001
Upper	7 (11.1)	8 (2.3)
Mid	31 (49.2)	98 (27.8)
Lower	25 (39.7)	246 (69.9)
Histology, n (%)			0.85
Well differentiated	32 (50.8)	163 (46.3)
Moderate differentiated	24 (38.1)	156 (44.3)
Poorly differentiated	3 (4.8)	27 (7.7)
Signet ring cell	4 (6.3)	6 (1.7)
Procedure time, min (mean ± SD)	58.9 ± 43.8	48.5 ± 35.4	0.04