Stratifying the risk of lymph node metastasis in undifferentiated-type early gastric cancer

Table 1 Characteristics of 567 patients included in the study n (%)

Factor	Value
Age, yr, mean ± SD	59.9 ± 12.3
Gender
Male	312 (55.1)
Female	255 (44.9)
Location
Upper	72 (12.7)
Middle	347 (61.2)
Lower	148 (26.1)
Size, mm, mean ± SD	26.8 ± 17.6
Form
Protrusion	39 (6.9)
Flat or depression	528 (93.1)
Ulceration	132 (23.4)
Depth
Mucosal (m)	310 (54.7)
Submucosal (sm)	257 (45.3)
Histology
Sig	315 (55.5)
Por	246 (43.4)
Muc	6 (1.1)
Mixed type	101 (17.8)
Lymphatic involvement	135 (23.8)
Venous involvement	47 (8.3)
Lymph node metastasis	44 (7.8)

Mixed type; histological mixture of differentiated and undifferentiated components; undifferentiated-predominant type. Sig: Signet ring cell carcinoma; Por: Poorly differentiated adenocarcinoma; Muc: Mucinous adenocarcinoma.

Table 2 Univariate analysis of risk factors for lymph node metastasis in patients with undifferentiated-type early gastric cancer

Factor	Patients (LNM)n (%)	Lymph node metastasis		P value
		Positiven = 44	Negativen = 523
Age				0.118
≤ 60 yr	296 (6.1)	18	278
> 60 yr	271 (9.6)	26	245
Gender				0.573
Male	312 (8.3)	26	286
Female	255 (7.1)	18	237
Location				0.050
Upper	72 (8.3)	6	66
Middle	347 (5.8)	20	327
Lower	148 (12.2)	18	130
Size				< 0.001
≤ 2 cm	268 (2.2)	6	262
> 2 cm	299 (12.7)	38	261
Form				0.002
Protrusion	39 (20.5)	8	31
Flat or depression	528 (6.8)	36	492
Ulceration				0.306
Absent	435 (7.1)	31	404
Present	132 (9.9)	13	119
Depth				< 0.001
Mucosal (m)	310 (2.9)	9	301
Submucosal (sm)	257 (13.6)	35	222
Histology				0.592
Sig	315 (6.7)	21	294
Por	246 (9.3)	23	223
Muc	6 (0)	0	6
Mixed type				0.003
No	466 (6.2)	29	437
Yes	101 (14.9)	15	86
Lymphatic involvement				< 0.001
Negative	432 (1.4)	6	426
Positive	135 (28.1)	38	97
Venous involvement				< 0.001
Negative	520 (6.5)	34	486
Positive	47 (21.3)	10	37

Values in parentheses are percentages of patients with lymph node metastasis (LNM). Sig: Signet ring cell carcinoma; Por: Poorly differentiated adenocarcinoma; Muc: Mucinous adenocarcinoma.

Table 3 Multivariate analysis of risk factors for lymph node metastasis in patients with undifferentiated-type early gastric cancer

Factor	Without lymphatic-vascular involvement		With lymphatic-vascular involvement
	OR (95%CI)	P value	OR (95%CI)	P value
Size of tumor (> 2 cm)	5.00 (2.03-12.30)	< 0.001	3.62 (1.39-9.46)	0.009
Form (protrusion)	0.58 (0.23-1.46)	0.245	0.72 (0.25-2.06)	0.534
Depth (submucosal)	4.37 (2.00-9.55)	< 0.001	0.46 (0.14-1.58)	0.218
Ulceration	1.38 (0.66-2.84)	0.394	1.40 (0.61-3.22)	0.426
Mixed type	1.63 (0.80-3.35)	0.180	2.01 (0.87-4.67)	0.103
Lymphatic involvement	-	-	40.7 (11.37-145.69)	< 0.001
Venous involvement	-	-	0.84 (0.32-2.24)	0.733

Table 4 Studies for factors and their conditions required for low incidence of lymph node metastasis in patients with undifferentiated-type early gastric cancer

Ref.	Country	Condition for low LNM incidence						Pts in the condition	Pts with LNM	LNM (95%CI)
		Size (cm)	Depth	LI	VI	UL	Other
Yamao et al[8]	Japan	< 3	m	LI(-)	VI(-)	UL(-)		277	1	0.36% (0.06-2.02)
Gotoda et al[1]	Japan	≤ 2	m	LI(-)	VI(-)	UL(-)		141	0	0% (0-2.6)
Ye et al[9]	South Korea	< 2.5	m	LI(-)	NS	NS		131	0	0% (0-2.28)
			sm1
Li et al[10]	China	≤ 2	m	LI(-)	VI(-)	NT		201	1	0.5% (0.08-2.76)
Ha et al[11]	South Korea	< 2	m	LI(-)	NT	NT	Sig	77	0	0% (0-4.75)
Hirasawa et al[2]	Japan	≤ 2	m	LI(-)	VI(-)	UL(-)		310	0	0% (0-0.96)
Kunisaki et al[12]	Japan	≤ 2	m	LI(-)	VI(-)		Por	84	0	0% (0-4.37)
1Lee et al[13]	South Korea	≤ 2	m	LI(-)	NS	NS	Male	124	4	3.2% (1.26-8.00)
This study	Japan	≤ 2	m	LI(-)	NS	NS		161	0	0% (0-2.33)

¹Study for patients with poorly differentiated adenocarcinoma. LNM: Lymph node metastasis; m: Mucosal cancer; sm: Submucosal cancer; Pts: Patients; LVI: Lymph-vascular involvement; LI: Lymphatic involvement; VI: Venous involvement; UL: Ulceration; NS: Not significant; NT: Not tested.