Table 1. Clinical data of patients with positive SLNs from MSKCC, SOC and PKUPH.

	MSKCC		SOC			PKUPH
Total patients	702		285			120
Patient and Tumor Characteristics	n	%	n	%	Mean	n	%	Mean
Age(years)					55.8			52.53
≤50	290	41.3				59	49.2
>50	412	58.7				61	50.8
Tumor size (cm)
≤1.0	155	22.1	31	10.9		25	20.8
>1.0 to ≤2.0	312	44.4	125	43.9		64	53.3
>2.0 to ≤3.0	154	21.9	129	45.2		22	18.3
>3.0	81	11.6				9	7.5
Tumor type
Ductal	618	88.0	246	86.3		73	60.8
Lobular	84	12.0	27	9.5		6	0.1
Mixed			11	3.9		38	31.7
Special type			1	0.4		3	2.5
Nuclear grade
I	22	3.1	91	31.9		13	10.8
II	321	45.7	120	42.1		74	61.7
III	275	39.2	74	26.0		27	22.5
Lobular	84	12.0				6	5.0
LVI
Yes	284	40.5	95	33.3		14	11.7
No	418	59.5	118	41.4		106	88.3
Unknown			72	25.3
Multifocality
Yes	197	28.1				9	7.5
No	505	71.9				111	92.5
ER status
+	567	80.8	194	68.1		101	84.2
−	135	19.2	38	13.3		19	15.8
Unknown			53	18.6
Method of SLN detection
Frozen section	463	66.0				99	82.5
Routine HE	65	9.3	220	77.2		21	17.5
Serial HE	78	11.1
IHC	63	9.0	65	22.8
Unknown	33	4.7
Number of positive SLNs
1	488	69.5	208	73.0		74	61.7
2	161	22.9	61	21.4		30	25.0
>2	53	7.6	16	5.6		16	13.3
Number of negative SLNs
0	271	38.6				36	30.0
1	183	26.1				17	14.2
2	102	14.5				20	16.7
>2	146	20.8				47	39.2
Size of SLN metastasis (mm)
≤2			264	92.7		44	36.7
>2			21	7.4		76	63.3
NSLN positive
+	264	37.6	101	35.4		45	37.5
−	438	62.4	184	64.6		75	62.5