Relationship between subgroups of central and lateral lymph node metastasis in clinically node-negative papillary thyroid carcinoma

Table 1 Clinicopathological characteristics and univariate analysis of lymph node metastasis in ipsilateral level-II, level-III, level-IV and lateral lymph nodes

Clinicopathological factor		Lateral lymph node metastasis			Ipsilateral lymph node metastasis level II			Ipsilateral lymph node metastasis level III			Ipsilateral lymph node metastasis level IV
		Positive, n = 181	Negative, n = 207	P value	Positive, n = 77	Negative, n = 311	P value	Positive, n = 126	Negative, n = 262	P value	Positive, n = 104	Negative, n = 284	P value
Age (yr)	< 55	147 (81.2)	169 (81.6)	0.914	59 (76.6)	257 (82.6)	0.224	101 (80.2)	215 (82.1)	0.652	87 (87.3)	229 (80.6)	0.498
	≥ 55	34 (18.8)	38 (18.4)		18 (23.4)	54 (17.4)		25 (19.8)	47 (17.9)		17 (16.3)	55 (19.4)
Sex	Female	118 (65.2)	154 (74.4)	0.048	44 (57.1)	228 (73.3)	0.006	85 (67.5)	187 (71.4)	0.430	70 (67.3)	202 (71.1)	0.467
	Male	63 (34.8)	53 (25.6)		33 (42.9)	83 (26.7)		41 (32.5)	75 (28.6)		34 (32.7)	82 (28.9)
Primary tumor size	> 2 cm	44 (24.3)	21 (10.1)	< 0.001	24 (31.2)	41 (13.2)	< 0.001	32 (25.4)	33 (12.6)	0.002	29 (27.9)	36 (12.7)	< 0.001
	≤ 2 cm	137 (75.7)	186 (89.9)		53 (68.8)	270 (86.8)		94 (74.6)	229 (87.4)		75 (72.1)	248 (873)
Tumor location	UP	57 (31.5)	45 (21.7)	0.029	31 (40.3)	71 (22.8)	0.002	38 (30.2)	64 (24.4)	0.230	28 (26.9)	74 (26.1)	0.864
	Non-UP	124 (68.5)	162 (78.3)		46 (59.7)	240 (77.2)		88 (69.8)	198 (75.6)		76 (73.1)	210 (73.9)
Multifocality	Yes	27 (14.9)	21 (10.1)	0.154	15 (19.5)	33 (10.6)	0.034	19 (15.1)	29 (11.1)	0.261	17 (16.3)	31 (10.9)	0.150
	No	154 (85.1)	186 (89.9)		62 (80.5)	278 (89.4)		107 (84.9)	233 (88.91)		87 (83.7)	253 (89.1)
ETE	Yes	78 (43.1)	58 (28.0)	0.002	38 (49.4)	98 (31.5)	0.003	54 (42.9)	82 (31.3)	0.025	52 (50.01)	84 (29.6)	< 0.001
	No	103 (56.9)	149 (72.0)		39 (50.6)	213 (68.5)		72 (57.1)	180 (68.7)		52 (50.0)	200 (70.4)
HT	Yes	36 (19.9)	44 (21.3)	0.740	11 (14.3)	69 (22.2)	0.125	28 (22.2)	52 (19.8)	0.344	21 (20.2)	59 (20.8)	0.900
	No	145 (80.1)	163 (78.7)		66 (85.7)	242 (77.8)		88 (77.8)	210 (80.2)		83 (79.8)	225 (79.2)
CLNM	0	17 (9.4)	86 (41.5)	< 0.001	10 (13.0)	93 (29.9)	< 0.001	14 (11.1)	89 (34.0)	< 0.001	6 (5.8)	97 (34.2)	< 0.001
	1-2	45 (24.9)	65 (31.4)		18 (23.4)	92 (29.6)		30 (23.8)	80 (30.5)		22 (21.2)	88 (31.0)
	≥ 3	119 (65.7)	56 (27.1)		49 (63.6)	126 (40.5)		82 (65.1)	93 (35.5)		76 (73.1)	99 (34.9)
Prelaryngeal LNM	0	113 (62.4)	180 (87.0)	< 0.001	44 (57.1)	249 (80.1)	< 0.001	82 (65.1)	21 (80.5)	0.001	66 (63.5)	37 (79.9)	< 0.001
	1-2	62 (34.3)	25 (12.1)		29 (37.7)	58 (18.6)		38 (30.2)	49 (18.7)		36 (34.6)	51 (18.0)
	≥ 3	6 (3.30)	2 (1.00)		4 (5.2)	4 (1.3)		6 (4.8)	2 (0.8)		2 (1.9)	6 (2.1)
Pretracheal LNM	0	65 (35.9)	134 (64.7)	< 0.001	32 (41.6)	167 (53.7)	0.121	41 (32.5)	158 (60.3)	< 0.001	33 (31.7)	166 (58.5)	0.002
	1-2	60 (29.0)	74 (40.9)		30 (39.0)	104 (33.4)		51 (40.5)	83 (31.7)		47 (45.2)	87 (30.6)
	≥ 3	42 (23.2)	13 (6.3)		15 (19.5)	40 (12.9)		34 (27.0)	21 (8.0)		24 (23.1)	31 (10.9)
Ipsilateral paratracheal LNM	0	46 (25.4)	121 (58.5)	< 0.001	20 (26.0)	147 (47.3)	< 0.001	36 (28.6)	131 (50.0)	< 0.001	20 (19.2)	147 (51.8)	< 0.001
	1-2	73 (40.3)	64 (30.9)		26 (33.8)	111 (35.7)		42 (33.3)	95 (36.3)		45 (43.3)	92 (32.4)
	≥ 3	62 (34.3)	22 (10.6)		31 (40.3)	53 (17.0)		48 (38.1)	36 (13.7)		39 (37.5)	45 (15.8)

HT: Hashimoto’s thyroid; PTC: Papillary carcinoma; ETE: Extrathyroid extension; CLNM: Central lymph node metastasis; LNM: Lymph node metastasis; UP: Tumors located in the upper lobe of the thyroid gland; Non-UP: Tumors located in the middle lobe, lower lobe, isthmus and whole.