Clinicopathological factors	Variables	No. of patients	5y CSS rates^a (%)	P-value
Age	75≤	42	73.5	0.50
Age	<75	192	79.1	0.50
Gender	Male	132	78.6	0.79
Gender	Female	102	77.9	0.79
Location	Proximal	70	78.6	0.86
Location	Distal	164	78.2	0.86
Preoperative CEA	Elevated	135	77.5	0.34
Preoperative CEA	Normal	99	81.8	0.34
Differentiation	Low grade^b	218	79.9	0.01
Differentiation	High grade^c	16	56.3	0.01
Invasion depth	T1 - T3	149	86.8	<0.001
Invasion depth	T4	85	62.3	<0.001
Lymphatic invasion	None-mild	78	94.3	<0.001
Lymphatic invasion	Moderate-severe	156	70.6	<0.001
Venous invasion	None-mild	131	88.1	<0.001
Venous invasion	Moderate-severe	103	65.4	<0.001
No. of dissected lymph nodes	12≤	182	78.6	0.93
No. of dissected lymph nodes	<12	52	77.4	0.93
TNM classification, 7^th edition	IIIA, IIIB	192	83.4	<0.001
TNM classification, 7^th edition	IIIC	42	54.9	<0.001