Subclassification scheme for adenocarcinomas of the esophagogastric junction and prognostic analysis based on clinicopathological features

Table 1 Patient characteristics, mean ± SD

Characteristic	Variables	n	%
Age (year)	62.4 ± 8.5
	≤ 65	95	62.1
	> 65	58	37.9
Sex	Male	126	82.4
	Female	27	17.6
Maximal tumor size (mm)	44.2 ± 15.5
	≤ 40 mm	86	56.2
	> 40 mm	67	43.8
Esophageal invasion length (mm)	13.4 ± 13.8
	< 20 mm	101	66.0
	≥ 20 mm	52	34.0
Siewert classification	I	11	7.2
	II	142	92.8
Nishi classification	E = G	5	3.3
	GE	74	48.4
	EG	7	4.6
	Not applicable	67	43.8
This classification	E	22	14.4
	Eg	31	20.3
	Ge	100	65.4
Surgical approaches	Transthoracic approach	27	17.6
	Transabdominal hiatal approach	126	82.4
Extent of surgical resection	Subtotal esophagectomy with partial gastrectomy	27	17.6
	Proximal gastrectomy with partial esophagectomy	34	22.2
	Total gastrectomy with partial esophagectomy	92	60.1
Histologic type	Adenocarcinoma	145	94.8
	Mixed adenocarcinoma	8	5.2
Histological grade	Well-moderately differentiated	72	47.1
	Moderately-poorly differentiated	80	52.3
Lauren type	Intestinal type	56	36.6
	Diffuse type	44	28.8
	Mixed type	51	33.3
Preoperative chemotherapy	No	104	68.0
	Yes	49	32.0
Vessel invasion	No	128	83.7
	Yes	25	16.3
Perineural invasion	No	73	47.7
	Yes	80	52.3
Pathological depth of tumor invasion	T1-2	48	31.4
	T3-4	105	68.6
Lymph node metastasis	N0	73	47.7
	N1-3	80	52.3
Distant metastasis	pM0	147	96.1
	pM1	6	3.9
TNM-GC staging system	IA	24	15.7
	IB	16	10.5
	IIA	8	5.2
	IIB	33	21.6
	IIIA	30	19.6
	IIIB	28	18.3
	IIIC	8	5.2
	IV	6	3.9
TNM-EC staging system	IA	5	3.3
	IB	17	11.1
	IC	16	10.5
	IIA	1	0.7
	IIB	4	2.6
	IIIA	5	3.3
	IIIB	49	32.0
	IIIC/IVA	50	32.7
	IVB	6	3.9

TNM: Tumor node metastasis; GC: Gastric cancer; EC: Esophageal cancer.

Table 2 Comparison of clinicopathological characteristics, mean ± SD

Characteristic	Variables	Type E	Type Eg	Type Ge	P value
Age (year)		61.5 ± 11.7	61.0 ± 9.7	63.0 ± 7.2	0.417
	≤ 65	13	20	62
	> 65	9	11	38	0.922
Sex	Male	18	26	82	0.969
	Female	4	5	18
Tumor size (mm)		53.0 ± 18.2	58.7 ± 12.6	37.9 ± 11.2	0.000a
	≤ 40 mm	7	4	75	0.000a
	> 40 mm	15	27	25
Esophageal invasion length (mm)		35.9 ± 13.0	23.9 ± 6.0	5.1 ± 5.4	0.000a
	< 20 mm	1	0	100	0.000a
	≥ 20 mm	21	31	0
Surgical approaches	Transthoracic approach	19	8	0	0.000a
	Transabdominal hiatal approach	3	23	100
Extent of surgical resection	Subtotal esophagectomy with partial gastrectomy	19	8	0	0.000a
	Proximal gastrectomy with partial esophagectomy	3	5	26
	Total gastrectomy with partial esophagectomy	0	18	74
Histologic type	Adenocarcinoma	18	30	97	0.013a
	Mixed adenocarcinoma	4	1	3
Histological grade	Well-moderately differentiated	9	8	55	0.016a
	Moderately-poorly differentiated	12	23	45
Lauren type	Intestinal type	7	6	43	0.150
	Diffuse type	7	13	24
	Mixed type	7	12	32
Preoperative chemotherapy	No	20	19	65	0.042a
	Yes	2	12	35
Vessel invasion	No	18	24	86	0.512
	Yes	4	7	14
Perineural invasion	No	10	14	49	0.908
	Yes	12	17	51
Pathological depth of tumor invasion	T1-2	6	4	38	0.028a
	T3-4	16	27	62
Lymph node metastasis	N0	9	7	57	0.003a
	N1-3	13	24	43
Distant metastasis	M0	21	29	97	0.679
	M1	1	2	3
	I-II	11	8	62	0.002a
	III-IV	11	23	38
TNM-GC staging system	I-II	11	8	62	0.002a
	III-IV	11	23	38
TNM-EC staging system	I-II	2	4	27	0.003a
	III-IV	20	27	63

^aP < 0.05.

TNM: Tumor node metastasis; GC: Gastric cancer; EC: Esophageal cancer.

Table 3 Number of patients with positive nodes

Variable	Variable	Type E	Type Eg	Type Ge	P value
Overall		13/22	24/31	43/100	0.003a
The rate of lymph node metastasis	≤ 15%	2	11	27	0.010a
	> 15%	11	13	16
Pathological depth of tumor invasion	T1-2	4	3	4	0.141
	T3-4	9	21	39
Pathological depth of tumor invasion	T1	0/1	0/1	1/23	0.956
	T2	4/5	1/3	3/15	0.051
	T3		2/3	2/4	0.659
	T4	9/16	21/24	37/58	0.058
Location of lymph node	No. 1	6	19	19	0.017a
	No. 2	0	9	18	0.018a
	No. 3	2	15	26	0.010a
	No. 4	1	6	9	0.443
	No. 5	0	5	4	0.134
	No. 6	0	1	2	0.735
	No. 7	12	20	27	0.047a
	No. 8	0	2	4	0.527
	No. 9	1	4	9	0.541
	No. 10	0	0	1	0.647
	No. 11	0	4	8	0.249
	No. 20	2	1	0	0.038a
	No. 21	1	0	0	0.074

^aP < 0.05.

Table 4 Univariate Cox proportional hazards analysis of overall survival

Variable	Hazard ratio	95% confidence interval	P value
This study classification
Type E	1.0		0.002
Type Eg	0.774	0.366-1.640	0.504
Type Ge	0.331	0.167-0.656	0.002
Age
< 65 years	1.0
≥ 65 years	1.110	0.647-1.904	0.705
Sex
Male	1.0
Female	0.850	0.416-1.738	0.657
Tumor size
≤ 40 mm	1.0
> 40 mm	2.235	1.307-3.823	0.003
Esophageal invasion length
< 20 mm	1.0
≥ 20 mm	2.431	1.355-4.362	0.003
Histologic type
Adenocarcinoma	1.0
Mixed adenocarcinoma	2.775	1.102-6.988	0.030
Histological grade
Well-moderately differentiated	1.0
Moderately-poorly differentiated	1.707	0.993-2.936	0.053
Lauren type
Intestinal type	1.0		0.207
Diffuse type	1.776	0.922-3.418	0.086
Mixed type	1.538	0.798-2.964	1.198
Preoperative chemotherapy
No	1.0
Yes	1.484	0.865-2.547	0.152
Vessel invasion
No	1.0
Yes	3.688	2.069-6.573	0.000
Perineural invasion
No	1.0
Yes	2.523	1.420-4.484	0.002
Pathological depth of tumor invasion
T1-2	1.0
T3-4	6.159	2.452-15.471	0.000
Lymph node metastasis
L0	1.0
L1	5.821	2.928-11.570	0.000
Distant metastasis
M0	1.0
M1	2.931	1.053-8.159	0.040

Table 5 Multivariate Cox proportional hazards analysis of overall survival

Variable	Hazard ratio	95% confidence interval	P value
This study classification
Type E	1.0		0.004
Type Eg	0.451	0.207-0.984	0.045
Type Ge	0.300	0.147-0.609	0.001
Vessel invasion
V0	1.0
V1	2.545	1.399-4.631	0.002
Perineural invasion
P0	1.0
P1	1.129	0.599-2.127	0.709
Pathological depth of tumor invasion
T1-2	1.0
T3-4	2.945	1.095-7.922	0.032
Lymph node metastasis
L0	1.0
L1	3.643	1.728-7.678	0.001

Table 6 Comprehensive comparison of staging systems for gastric cancer and esophageal adenocarcinoma in adenocarcinoma of the esophagogastric junction patients

Project	Likelihood ratio χ2 price		Linear trend χ2 price		The log-likelihood estimate
	Gastric cancer TNM staging system	Esophageal cancer TNM staging system	Gastric cancer TNM staging system	Esophageal cancer TNM staging system	Gastric cancer TNM staging system	Esophageal cancer TNM staging system
Type E	10.896	6.615	3.327	5.178	37.018	37.300
Type Eg	17.032	18.760	11.923	9.899	55.624	62.748
Type Ge	13.514	7.575	2.873	1.196	181.106	186.322

TNM: Tumor node metastasis.