6.

Definitions of N categories and their impact on prognostic value of staging

Characteristics	n	5-year OS (%)	Univariate analysis			Multivariate analysis		−2 log-likelihood
			χ2	P		HR (95% CI)	P
lvN, lymphovascular-node; OS, overall survival; HR, hazard ratio; 95% CI, 95% confidence interval.
Model 1
N stage			181.400	<0.001		1.605 (1.491−1.729)	<0.001	4,765.196
N0	459	80.1				1 (ref)
N1	172	61.1				2.149 (1.156−2.959)	<0.001
N2	174	49.9				3.156 (2.348−4.242)	<0.001
N3a	141	43.3				4.212 (3.115−5.697)	<0.001
N3b	61	26.2				7.256 (5.060−10.404)	<0.001
Age at surgery						1.746 (1.326−2.299)	<0.001
Depth of invasion						1.226 (1.055−1.425)	0.008
Borrmann type						1.218 (1.019−1.455)	0.030
Tumor deposits						1.674 (1.314−2.132)	<0.001
Model 2
lvN stage			196.855	<0.001		1.642 (1.522−1.771)	<0.001	4,746.922
lvN0	407	82.5				1 (ref)
lvN1	190	65.2				2.053 (1.461−2.886)	<0.001
lvN2	120	51.5				3.473 (2.451−4.920)	<0.001
lvN3a	229	42.9				4.550 (3.401−6.088)	<0.001
lvN3b	61	26.2				8.256 (5.667−12.029)	<0.001
Age at surgery						1.744 (1.326−2.295)	<0.001
Depth of invasion						1.208 (1.039−1.404)	0.014
Borrmann type						1.213 (1.016−1.448)	0.032
Tumor deposits						1.622 (1.278−2.059)	<0.001