Table 5. Lymph node metastasis rate percentages in T classification, histology type and differentiation subgroups.

T classification	% LNMR	n/N	Histology type	% LNMR	n/N	Differentiation	% LNMR	n/N
Tis–T1	28.0	15/586	Squamous cell carcinoma	57.6	21/7879	Well	37.4	6/597
T2	46.2	16/1531				Moderate	52.8	6/1474
T3	61.0	17/3587	Adenocarcinoma	61.4	3/836	Poor	67.5	6/509
T4	72.9	15/1084				Others	57.7	6/122

LNMR, lymph node metastasis rate; n/N, the number of studies referred to the characteristic/the total number of patients in the referred studies.