Biopathologic features and clinical significance of micrometatasis in the lymph node of early gastric cancer

Table 1 Clinicopathologic features according to the classification of lymph node metastasis (n = 90)

	Micrometastasis	Macrometastasis	P value
	(n = 37)	(n = 53)
Age (yr)	56.9 ± 12.9	59.2 ± 11.1	0.377
Sex			0.665
Male	22 (59.5)	34 (64.2)
Female	15 (40.5)	19 (35.8)
Depth of invasion			0.966
Mucosa	5 (13.5)	7 (13.2)
Submucosa	32 (86.5)	46 (86.8)
Tumor size (cm)	4.7 ± 2.8	4.5 ± 2.0	0.652
Histology			0.522
Differentiated	18 (48.6)	30 (56.6)
Undifferentiated	19 (51.4)	23 (43.4)
Lauren classification			0.162
Intestinal	19 (51.4)	35 (66.0)
Diffuse, mixed	18 (48.6)	18 (34.0)
Lymphovascular invasion			0.832
Absent	17 (45.9)	23 (43.4)
Present	20 (54.1)	30 (56.6)
Metastatic LNs (n)	1.7 ± 1.3	2.2 ± 1.3	0.085
Japanese N2 station involvement1			0.338
No	26 (89.7)	34 (79.1)
Yes	3 (10.3)	9 (20.9)
Main tumor burden in LN (mm)	0.9 ± 0.5	4.6 ± 4.6	< 0.001
Pattern of metastasis in LNs			0.694
Single cluster	14 (37.8)	18 (34.0)
Multiple cluster	22 (59.5)	33 (62.3)
Diffuse	1 (2.7)	2 (3.8)
Location of metastasis in LNs			< 0.001
Marginal sinus	17 (45.9)	1 (1.9)
Non marginal sinus	20 (54.1)	52 (98.1)
Gastric resection			0.423
Open subtotal	27 (73.0)	40 (75.5)
Open total	2 (5.4)	6 (11.3)
LADG	8 (21.6)	7 (13.2)
Lymph node dissection			0.261
D1 + β	15 (40.5)	15 (28.3)
D2	22 (59.5)	38 (71.7)
Dissected LNs (n)	36.2 ± 11.1	38.6 ± 15.6	0.424
Adjuvant chemotherapy			0.503
No	11 (29.7)	20 (37.7)
Yes	26 (70.3)	33 (62.3)
Recurrence			0.041
Absent	37 (100)	47 (88.7)
Present	0 (0)	6 (11.3)

¹Available data only. Data are expressed as absolute numbers (percentage) or mean ± SD. LN: Lymph node; LADG: Laparoscopically assisted distal gastrectomy.

Table 2 Biologic features according to the classification of lymph node metastasis (n = 90)

	Micrometastasis	Macrometastasis	P value
Ki-67 (primary tumor)
Examed tissue	33	51
Positive cell	59.3% ± 24.0%	62.3% ± 20.9%	0.553
TUNEL (primary tumor)
Examed tissue	30	51
Positive cell	2.4% ± 1.7%	4.5% ± 4.4%	0.004
Ki-67 (lymph node)
Examed tissue	33	50
Positive cell	26.7% ± 18.0%	40.5% ± 24.1%	0.004
TUNEL (lymph node)
Examed tissue	25	51
Positive cell	1.0% ± 1.0%	3.0% ± 3.5%	< 0.001

Data are expressed as absolute numbers (percentage) or mean ± SD. TUNEL: Terminal deoxynucleotidyl transferase dUTP nick end labeling.

Table 3 Recurrence and associated factors (n = 90)

	No recurred (n = 84)	Recurred (n = 6)	P value
Age (yr)	57.8 ± 12.0	64.8 ± 7.4	0.159
Sex			1.000
Male	52 (61.9)	4 (66.7)
Female	32 (38.1)	2 (33.3)
Depth of invasion			1.000
Mucosa	12 (14.3)	0 (0)
Submucosa	72 (85.7)	6 (100)
Tumor size (cm)	4.7 ± 2.5	3.7 ± 1.27	0.321
Histology			0.681
Differentiated	44 (52.4)	4 (66.7)
Undifferentiated	40 (47.5)	2 (33.3)
Lauren			0.396
Intestinal	49 (58.3)	5 (83.3)
Diffuse, mixed	35 (41.7)	1 (16.7)
Lymphovascular invasion			0.032
Absent	40 (47.6)	0 (0)
Present	44 (52.4)	6 (100)
Metastatic LNs (n)	2.0 ± 1.3	2.2 ± 1.2	0.816
Classification of nodal metastasis			0.041
Micrometastasis	37 (44.0)	0 (0)
Macrometastasis	47 (56.0)	6 (100)
Japanese N2 station involvement1			0.127
No	58 (85.3)	2 (50.0)
Yes	10 (14.7)	2 (50.0)
Main tumor burden in LN (mm)	3.0 ± 4.1	4.0 ± 1.5	0.594
Pattern of metastasis in LNs			0.450
Single cluster	28 (33.3)	4 (66.7)
Multiple cluster	54 (64.3)	1 (16.7)
Diffuse	2 (2.4)	1 (16.7)
Location of metastasis in LNs			0.090
Marginal sinus	31 (36.9)	0 (0)
Non marginal sinus	53 (63.1)	6 (100)
Gastric resection			1.000
Open subtotal	63 (75.0)	4 (66.7)
Open total	7 (8.3)	1 (16.7)
LADG	14 (16.7)	1 (16.7)
Lymph node dissection			1.000
D1 + β	28 (33.3)	2 (33.3)
D2	56 (66.7)	4 (66.7)
Dissected LNs (n)	37.4 ± 13.8	41.0 ± 16.4	0.538
Adjuvant chemotherapy			0.660
No	30 (35.7)	1 (16.7)
Yes	54 (64.3)	5 (83.3)
Ki-67 (primary tumor)1
Positive cell	61.3% ± 22.1%	58.3% ± 24.6%	0.748
TUNEL (primary tumor)1
Positive cell	3.6% ± 3.9%	4.6% ± 2.2%	0.552
Ki-67 (lymph node)1
Positive cell	35.0% ± 23.5%	35.0% ± 10.8%	0.996
TUNEL (lymph node)1
Positive cell	2.3% ± 3.2%	2.8% ± 1.1%	0.720

¹Available data only. Data are expressed as absolute numbers (percentage) or mean ± SD. LN: Lymph node; LADG: Laparoscopically assisted distal gastrectomy; TUNEL: Terminal deoxynucleotidyl transferase dUTP nick end labeling.

Table 4 Details of recurrent cases with pT1N1 in gastric cancer

Case	Age (yr)	Sex	T depth	T size	Histology	Lauren	LVI	Number of metastatic LNs	Size of metastasis (mm)	Pattern	Location	Tumor burden (mm)	Proportion	Extent of LND	Number of dissected LNs	Site of recurrence
1	62	M	Sm3	2.3	Undiff	Diffuse	Present	2	2.3	Single cluster	Parenchyme	2.5	40.0%	D1 + β	31	N3 LN
2	62	M	Sm3	3.0	Diff	Intestinal	Present	2	3.1	Single cluster	Parenchyme	3.88	26.0%	D2	59	Liver
3	72	M	Sm3	3.0	Diff	Intestinal	Present	1	3.6	Diffuse	Diffuse	9.62	65.0%	D1 + β	14	Peritoneum
4	59	M	Sm3	3.0	Diff	Intestinal	Present	4	5.5	Single cluster	Parenchyme	10.8	45.0%	D2	45	Liver, lung
5	76	F	Sm2	5.0	Diff	Intestinal	Present	1	6.0	Single cluster	Parenchyme	6.0	67.0%	D2	54	Liver
6	58	F	Sm3	5.5	Undiff	Intestinal	Present	3	3.2	Multiple cluster	Parenchyme	7.2	87.0%	D2	43	PALN

LVI: Lymphovascular invasion; LN: Lymph node; LND: Lymph node dissection; PALN: Para-aortic lymph node; Diff: Differentiate; Undiff: Undifferentiate.