Risk factors for lymph node metastasis and evaluation of reasonable surgery for early gastric cancer

Table 1 Site and frequency of lymph node metastasis of cancer in the lower and middle thirds of stomach

The lower third of the stomach	Frequency of LNM		The middle third of the stomach	Frequency of LNM
	Possitive	%		Possitive	%
Group 1		Group 1
No.3	12	4.9	No.1	3	4.8
No.4	16	6.5	No.3	6	9.7
No.5	3	1.2	No.4	0	0.0
No.6	14	5.7	No.5	1	1.6
			No.6	1	1.6
Total	35	14.3	Total	8	12.9
Group 2		Group 2
No.1	1	0.4	No.7	3	4.8
No.7	13	5.3	No.8a	1	1.6
No.8a	7	2.9	No.9	0	0.0
No.9	2	0.8	No.11p	0	0.0
No.11p	0	0.0	No.12a	0	0.0
No.12a	0	0.0
No.14v	0	0.0
Total	18	7.3	Total	4	6.5

LNM: Lymph node metastasis; No.1: Right paracardial LN; No.3: LN along the lesser curvature; No.4: LN along the greater curvature; No.5: suprapyloric LN; No.6: Infrapyloric LN; No.7: LN along the left gastric artery; No.8a: LN along the common hepatic artery (anterosuperior group); No.9: LN around the celiac artery; No.11p: LN along the proximal splenic artery; No.12a: LN in the hepatoduodenal ligament (along the hepatic artery); No.14v: LN along the superior mesenteric vein.

Table 2 Comparison of clinicopathological features between patients with and without lymph node metastasis

Factors	Node negative	Node positive	P value
Dissected nodes (mean ± SD)	19.3 ± 7.5	20.8 ± 6.9	0.188
Age, yr (mean ± SD)	53.9 ± 12.1	52.9 ± 13.2	0.606
Tumor maximum diameter (cm, mean ± SD)	3.1 ± 1.8	3.5 ± 1.8	0.197
Gender
Male	209	33
Female	66	14	0.465
Tumor location
Upper	11	0
Middle	53	9
Lower	207	38	0.435
Total	4	0
Depth of invasion
Mucosa	143	9
Submucosa	132	38	< 0.001
Histological type
Differentiated	130	12
Undifferentiated	145	35	0.007
Macroscopic type
Protruded	18	3
Flat	34	4	0.746
Depressed	223	40
Growth manner
Mass	87	15
Nest	79	12	0.891
Diffuse	109	20
lymphatic invasion
Negative	267	36
Positive	8	11	< 0.001

Differentiated: Papillary and tubular adenocarcinoma; Undifferentiated: Poorly differentiated adenocarcinoma and signet-ring cell carcinoma; Protruded:IandIIa; flat: IIb; depressed:IIc and III.

Table 3 Logistic regression analysis for variables associated with lymph node metastasis in EGC

Explanatory variables	Odds ratio	95% CI	P value
Depth of invasion	3.67	1.62-8.30	0.002
Histological type	3.39	1.39-8.27	0.007
Lymphatic invasion	8.41	2.86-24.74	< 0.001
Tumor maximum diameter	1.23	1.0-1.49	0.042
Gender	1.10	0.46-2.21	0.981
Age	0.99	0.97-1.03	0.726
Tumor location	0.60	0.29-1.23	0.161
Growth manner	0.58	0.26-1.30	0.186
Macroscopic type	1.14	0.56-2.34	0.715

CI: Confidence interval. Depth of invasion, histological type, lymphatic invasion and tumor maximum diameter are the independent risk factors correlated with lymph node involvement.

Table 4 Depth of invasion, histological type, macroscopic type, lymphatic penetration of lymph node metastasis and tumor maximum diameter in the lower third of stomach

Factors	Group 1 metastasis (person)						Group 2 metastasis (person)
	No.3	No.4	No.5	No.6	Total	P value	No.1	No.7	No.8a	No.9	Total	P value
Tumor maximum diameter (cm)
≤ 1.0	1	0	0	3	4		0	0	0	0	0
1.1-2.0	4	4	2	4	11		0	3	3	0	5
2.1-3.0	0	2	1	0	3		0	1	0	0	1
> 3.0	7	10	0	7	17	0.143	1	9	4	2	12	0.018
Histological type
Diff	4	4	0	4	8		0	2	0	1	2
Undiff	8	12	3	10	27	0.025	1	11	7	1	16	0.006
Depth of invasion
M	1	4	2	3	9		1	0	0	0	1
Sm	11	12	1	11	26	0.010	0	13	7	2	17	< 0.001
Growth manner
Mass	5	5	0	5	10		0	4	3	1	7
Nest	3	3	2	2	8	0.669	0	3	2	1	4	0.689
Diffuse	4	8	1	7	17		1	6	2	0	7
Macroscopic type
Protruded	0	2	0	0	2		0	0	0	0	0
Flat	1	2	0	1	3		0	2	0	0	2
Depressed	11	12	3	13	30	0.819	1	11	7	2	16	0.501
Lymphatic invasion
Negative	10	13	2	11	27		1	8	6	2	13
Positive	2	3	1	3	8	< 0.001	0	5	1	0	5	< 0.001

Diff: Differentiated histological type; Undiff: Undifferentiated histological type; M: Mucosa; Sm: Submucosa.