Risk of lymph node metastasis in mixed-type early gastric cancer determined by the extent of the poorly differentiated component

Table 1 Clinicopathological factors and lymph node metastasis in early gastric cancers n (%)

	Total	Lymph node status		P value
		Negative(n = 479)	Positive(n = 71)
Sex				0.950
Male	304	265 (87.2)	39 (12.8)
Female	246	214 (87.0)	32 (13.0)
Age (yr)	550	54.5 ± 0.7	55.5 ± 2.5	0.686
Site1				0.059
Upper	129	120 (93.0)	9 (7.0)
Middle	252	217 (86.1)	35 (13.9)
Lower	169	142 (84.0)	27 (16.0)
Gross type				0.030
Elevated	59	45 (76.3)	14 (23.7)
Flat	51	46 (90.2)	6 (9.8)
Depressed	440	388 (88.2)	52 (11.8)
Ulceration				0.640
Absent	445	389 (87.4)	56 (12.6)
Present	105	90 (85.7)	15 (14.3)
Tumour size (cm)2				< 0.0001
≤ 1	40	39 (97.5)	1 (2.5)
≤ 2	126	120 (95.2)	6 (4.8)
≤ 3	141	125 (88.7)	16 (11.3)
≤ 3	243	195 (80.2)	48 (19.8)
Depth of invasion3				< 0.0001
Mucosa	288	273 (94.8)	15 (5.2)
M2	50	49 (98.0)	1 (2.0)
M3	238	224 (94.1)	14 (5.9)
Submucosa	262	206 (78.6)	56 (21.4)
SM1	33	30 (90.9)	3 (9.1)
SM2	67	55 (82.1)	12 (17.9)
SM3	162	121 (74.7)	41 (25.3)
Depth (μm)	262	1754 ± 89.4	2017 ± 130.3	0.153
Perineural invasion				< 0.0001
Absent	495	442 (89.3)	53 (10.7)
Present	55	37 (67.3)	18 (32.7)
LV invasion				< 0.0001
Absent	518	464 (89.6)	54 (10.4)
Present	32	15 (46.9)	17 (53.1)

¹Between upper vs middle+lower;

²Between ≤ 2 cm vs > 2 cm;

³Between M vs SM. LV: Lymphovascular; M2: Lamina propria invasion; M3: Muscularis mucosae invasion without penetration; SM1: Upper third; SM2: Middle third; SM3: Lower third.