Table 3.

Correlation between lymph node metastatic ratio and tumor characteristics

Pathological	Lymph node < 20%	> 21%	P
characteristics	metastatic ratio
Size of tumor
< 4 cm	42	43	0.48
≥ 4 cm	9	74a
location
Lower third	5	8
Middle third	22	47
Upper third	24	63	< 0.001
Depth of invasion
Mucosa and submucosa	12	9
Muscle and subserosa	16	6
Serosa	23	103b	< 0.001

^aP < 0.05,

^bP < 0.05 vs the group with lymph node metastatic ratio less than 20%.