Prognostic assessment of different metastatic lymph node staging methods for gastric cancer after D2 resection

Table 1 Clinical and histopathological characteristics of the patients

Factors	n
Gender (male/female)	281/146
Age ( ≤ 60 yr/> 60 yr)	200/227
Site (antrum/body/fundus/others)	234/163/22/8
Size (< 3 cm/3-6 cm/≥ 6 cm)	36/216/175
Histological grade (well/moderately/poorly)	11/313/103
Depth of invasion (T1/T2/≥ T3)	4/79/344
Lymphatic/venous invasion (absence/presence)	359/68
Perineural invasion (absence/presence)	396/31
Examined lymph nodes (< 10/10-15/> 15)	126/152/149

Table 2 Staging criteria of positive lymph nodes, metastatic lymph node ratio and log odds of positive lymph nodes classifications n (%)

Grade	MLR		LODDS		pN
0	Nr = 0	139 (32.6)	Nr < -1	129 (30.2)	0	139 (32.6)
1	0 < Nr ≤ 0.2	79 (18.5)	-1 ≤ Nr < -0.5	87 (20.4)	1-2	78 (18.3)
2	0.2 < Nr ≤ 0.4	58 (13.6)	-0.5 ≤ Nr < 0	85 (19.9)	3-6	94 (22.0)
3/3a	0.4 < Nr ≤ 0.7	104 (24.4)	0 ≤ Nr < 0.5	76 (17.8)	7-15	86 (20.1)
4/3b	0.7 < Nr ≤ 1	47 (11.0)	Nr ≥ 0.5	50 (11.7)	> 15	30 (7.0)

MLR: Metastatic lymph node ratio; LODDS: Log odds of positive lymph nodes; pN: Positive lymph nodes.

Table 3 Univariate analysis of various prognostic factors correlated to retrieved lymph nodes n (%)

Variable		5-yr survival rate	Log rankχ2value	P value
Examined lymph nodes
< 10	126 (29.5)	57.1%	4.256	0.039
10-15	152 (35.6)	55.9%
> 15	149 (34.9)	45.0%
pN
0	139 (32.6)	80.6%	97.014	0.000
1-2	78 (18.3)	57.7%
3-6	94 (22.0)	44.7%
7-15	86 (20.1)	27.9%
> 15	30 (7.0)	3.3%
MLR
Nr = 0	139 (32.6)	80.6%	103.984	0.000
0 < Nr ≤ 0.2	79 (18.5)	62.0%
0.2 < Nr ≤ 0.4	58 (13.6)	50.0%
0.4 < Nr ≤ 0.7	104 (24.4)	26.9%
0.7 < Nr ≤ 1	47 (11.0)	12.8%
LODDS
Nr < -1	129 (30.2)	80.6%	96.214	0.000
-1 ≤ Nr < -0.5	87 (20.4)	63.2%
-0.5 ≤ Nr < 0	85 (19.9)	43.5%
0 ≤ Nr < 0.5	76 (17.8)	27.6%
Nr ≥ 0.5	50 (11.7)	14.0%

MLR: Metastatic lymph node ratio; LODDS: Log odds of positive lymph nodes; pN: Positive lymph nodes.

Table 4 Five-year overall survival of patients with ≤ 15 tested lymph nodes based on positive lymph nodes and metastatic lymph node ratio staging system

		MLR 0		MLR 1		MLR 2		MLR 3		MLR 4		χ2	P value
		n	5-YSR	n	5-YSR	n	5-YSR	n	5-YSR	n	5-YSR
< 10 LN	pN 0	59	76.30%	-	-	-	-	-	-	-	-	-	-
	pN 1	-	-	8	50%	14	57.10%	2	0%	3	0%	22.293	0
	pN 2	-	-	-	-	4	50%	22	31.80%	3	33.30%	0.51	0.775
	pN 3a	-	-	-	-	-	-	3	66.70%	8	37.50%	0.78	0.377
	χ2	-		-		0.258		9.278		1.658
	P	-		-		0.611		0.098		0.437
10-15 LN	pN 0	56	80.40%	-	-	-	-	-	-	-	-	-	-
	pN 1	-	-	24	62.50%	-	-	-	-	-	-	-	-
	pN 2	-	-	1	100%	20	50%	18	44.40%	-	-	0.755	0.686
	pN 3a	-	-	-	-	-	-	23	17.40%	10	20%	0.068	0.794
	χ2	-		0.836		-		3.613		-
	P	-		0.658		-		0.057		-

MLR: Metastatic lymph node ratio; 5-YSR: 5-year survival rate; LN: Examined lymph nodes; pN: Positive lymph nodes.

Table 5 Five-year overall survival of patients with ≤ 15 tested lymph nodes based on positive lymph nodes and log odds of positive lymph nodes staging system

		LODDS 0		LODDS 1		LODDS 2		LODDS 3		LODDS 4		χ2	P value
		n	5-YSR	n	5-YSR	n	5-YSR	n	5-YSR	n	5-YSR
< 10 LN	pN 0	33	81.80%	20	70%	6	66.7.0%	-	-	-	-	1.486	0.476
	pN 1	-	-	10	50%	12	58.30%	4	0	1	0	22.349	0
	pN 2	-	-	-	-	14	42.90%	13	30.80%	2	0	4.202	0.122
	pN 3a	-	-	-	-	-	-	3	66.70%	8	37.5%	0.78	0.377
	χ2	-		1.44		0.969		5.689		1.083
	P	-		0.23		0.619		0.128		0.582
10-15 LN	pN 0	56	80.40%	-	-	-	-	-	-	-	-	-	-
	pN 1	-	-	24	62.50%	-	-	-	-	-	-	-	-
	pN 2	-	-	4	75%	23	43.50%	12	50%	-	-	1.241	0.538
	pN 3a	-	-	-	-	2	0%	19	15.80%	12	25%	3.413	0.182
	χ2	-		0.222		6.785		3.614		-
	P	-		0.638		0		0.057		-

LODDS: Log odds of positive lymph nodes; 5-YSR: 5-year survival rate; LN: Examined lymph nodes; pN: Positive lymph nodes.