Superiority of metastatic lymph node ratio to the 7th edition UICC N staging in gastric cancer

Table 1 Univariate analysis of various clinicopathologic factors in 1042 cases of gastric cancer

Variable	n (%)	5-yr survival rate (%)	Log rankχ2value	Hazardratio	P value
Gender			0.433	1.060	0.511
Male	708 (67.9)	48.6
Female	334 (32.1)	45.1
Age (continuous)	1042 (100)	47.5	124.704	1.019	< 0.001
Tumor location			78.529	0.735	< 0.001
Proximal	579 (55.6)	39.0
Distal	418 (40.1)	62.0
Two-thirds or more	45 (4.3)	17.5
Tumor size (continuous)		47.5	124.704	1.147	< 0.001
Histological grade			18.407	1.254	< 0.001
Well/moderately differentiated adenocarcinoma	388 (37.2)	54.8
Poorly differentiated adenocarcinoma	448 (43.0)	44.7
Undifferentiated adenocarcinoma/signet-ring cell carcinoma/mucinous adenocarcinoma	206 (19.8)	39.8
Lymphatic/venous invasion			65.905	2.685	< 0.001
No	954 (91.6)	50.0
Yes	88 (8.4)	20.4
Depth of invasion (7th edition)			172.456	1.852	< 0.001
T1	81 (7.8)	90.7
T2	120 (11.5)	74.3
T3	195 (18.7)	57.5
T4a	538 (51.6)	35.9
T4b	108 (10.4)	22.1
The 7th edition UICC N			168.281	1.604	< 0.001
N0	332 (31.9)	71.1
N1	211 (20.2)	50.7
N2	268 (25.7)	37.5
N3	231 (22.2)	22.2
The 6th edition UICC N			160.982	1.571	< 0.001
N0	332 (31.9)	71.1
N1	479 (46.0)	43.3
N2	172 (16.5)	21.4
N3	59 (5.7)	25.1
Metastatic lymph node ratio			281.341	1.776	< 0.001
MLNR0	332 (31.9)	71.1
MLNR1	277 (26.6)	59.0
MLNR2	154 (14.8)	32.7
MLNR3	279 (26.8)	16.0
Retrieved lymph nodes			67.098	0.616	< 0.001
≤ 15	657 (63.1)	58.0
> 15	385 (36.9)	68.4

Table 2 Multivariate survival analysis results

Variables	Wald	P value	HR	95% CI
Age (continuous)	23.741	< 0.001	1.020	1.012-1.028
Tumor location	8.825	0.003	0.794	0.682-0.925
Tumor size (continuous)	29.678	< 0.001	1.085	1.054-1.118
Histological grade	11.542	0.001	1.222	1.089-1.372
Lymphatic/venous invasion	30.629	< 0.001	2.063	1.596-2.666
UICC 7th T	43.652	< 0.001	1.434	1.289-1.596
UICC 7th N	5.806	0.016	1.218	1.037-1.430
MLNR	14.693	< 0.001	1.330	1.149-1.538
Retrieved lymph nodes	29.666	< 0.001	0.548	0.441-0.680

CI: Confidence interval; UICC: International Union Against Cancer; HR: Hazard ratio; T: Tumor; N: Node; MLNR: Metastatic lymph node ratio.

Table 3 Comparison of the performance of the 6th and 7th edition International Union Against Cancer node staging systems and the metastatic lymph node ratio staging system

Classification	Subgroups	Linear trendχ2	Likelihood ratioχ2	AIC
6th ed UICC N staging	N 0, 1, 2, 3	117.751	141.517	7364.073
7th ed UICC N staging	N 0, 1, 2, 3	138.342	146.796	7325.731
MLNR staging	MLNR 0, 1, 2, 3	203.476	219.912	7240.017

UICC: International Union Against Cancer; N: Node; MLNR: Metastatic lymph node ratio; AIC: Akaike information criterion.