Predictive factors for lymph node metastasis and defining a subgroup treatable for laparoscopic lymph node dissection after endoscopic submucosal dissection in poorly differentiated early gastric cancer

Table 1 Univariate analysis of potential risk characteristics for lymph node metastasis n (%)

Factor	Lymph node metastasis
	Positive	P-value
Age (yr)
< 60 (n = 95)	16 (16.8)	0.494
≥ 60 (n = 43)	5 (11.6)
Sex
Male (n = 87)	14 (16.1)	0.748
Female (n = 51)	7 (13.7)
Macroscopic type
I (n = 6)	0 (0)	0.564
II (n = 82)	12 (14.6)
III (n = 50)	9 (18.0)
Family medical history
Positive (n = 11)	2 (18.2)	0.809
Negative (n = 127)	19 (15.0)
Location
Upper (n = 29)	4 (13.8)	0.497
Middle (n = 8)	0 (0)
Lower (n = 101)	17 (16.8)
Number of tumors
Single (n = 133)	20 (15.0)	0.799
Multitude (n = 5)	1 (20.0)
Tumor size in diameter
≤ 2 cm (n = 78)	5 (6.4)	0.005
> 2 cm (n = 60)	16 (26.7)
Ulceration
Negative (n = 109)	18 (16.5)	0.474
Positive (n = 29)	3 (10.3)
Lymphatic vessel involvement
Negative (n = 122)	11 (9.0)	< 0.001
Positive (n = 16)	10 (62.5)
Depth of invasion
Mucosa (n = 83)	5 (6.0)	0.002
Submucosa (n = 55)	16 (29.1)