Predictive factors for lymph node metastasis in early gastric cancer

Table 1 Extended indications for endoscopic mucosal resection/endoscopic submucosal dissection according to the treatment guidelines for gastric cancer in Japan

Differentiated type, mucosal cancer, ulcer (-), > 2 cm

Differentiated type, mucosal cancer, ulcer (+), ≤ 3 cm

Undifferentiated type, mucosal cancer, ulcer (-), ≤ 2 cm

Additional lymph node resection is not necessary when lymphovascular invasion is absent and also when it is not deeper than SM1 (-500 μm).

Table 2 Clinicopathological features of 556 patients diagnosed with early gastric cancer and univariate analysis of potential risk factors of regional lymph node metastasis

Variables	Positive rate of lymph node metastasis (%)	P value
Age (yr)		0.876
< 65	40/288 (13.9)
≥ 65	36/268 (13.4)
Gender		0.012
Male	35/330 (10.6)
Female	41/226 (18.1)
Size (cm)		< 0.001
< 2	34/352 (9.7)
≥ 2	42/204 (20.6)
Endoscopic appearance		0.993
Elevated	9/65 (13.8)
Depressed	43/307 (14.0)
Flat	16/123 (13.0)
Mixed	8/61 (13.1)
Serum CEA (ng/mL)		0.152
< 5	43/336 (12.8)
≥ 5	7/32 (21.9)
Depth of invasion		< 0.001
T1a	12/293 (4.1)
T1b	64/263 (24.3)
Histology differentiation		0.759
Differentiated	41/309 (13.3)
Undifferentiated	35/247 (14.2)
Vascular invasion		< 0.001
Absence	68/546 (12.5)
Presence	8/10 (80.0)
Lymphatic involvement		< 0.001
Absence	44/517 (8.5)
Presence	32/39 (8.2)
Ulcer		0.449
Absence	22/182 (12.1)
Presence	54/374 (14.4)

Table 3 Multivariate analysis of potential risk factors for regional lymph node metastasis

Variables	Odds ratio (95% CI)	P value
Gender (female/male)	1.49 (0.35-1.1)	0.163
Tumor size (≥ 2 cm/< 2 cm)	2.28 (1.20-4.17)	0.008
Vascular invasion (yes/no)	1.86 (0.23-12.65)	0.598
Lymphatic invasion (yes/no)	27.2 (10.3-74.8)	< 0.001
Depth of invasion (T1b/T1a)	4.91 (2.44-9.89)	< 0.001

Table 4 Incidence of lymph node metastasis in our patients fulfilled the criteria used in endoscopic treatment for early gastric cancer in Japan

Criteria	Patient number with lymph node metastasis/total patient	Incidence (%)
Non-ulcerated, differentiated, intramucosal tumor without lymphovascular invasion, ≤ 2 cm	0/42	0
Non-ulcerated, differentiated, intramucosal tumor without lymphovascular invasion, any size	0/77	0
Ulcerated, intramucosal tumor, without lymphovascular invasion, ≤ 3 cm	0/78	0
Non-ulcerated, undifferentiated intramucosal tumor without lymphovascular invasion, ≤ 2 cm	3/35	8.6