Table 2.

Clinicopathological parameters of included patients and association with SLN status.

	Negative (N = 9553)	Positive (N = 2338)	P value
Age
20–39 yr	190 (2.0%)	67 (2.9%)	<.001
40–59 yr	3398 (35.6%)	928 (39.7%)
60–79 yr	5341 (55.9%)	1192 (51.0%)
≥80 years	624 (6.5%)	151 (6.5%)
Race
W	7831 (82.0%)	1900 (81.3%)	.0517
B	842 (8.8%)	245 (10.5%)
AI	61 (0.6%)	14 (0.6%)
API	819 (8.6%)	179 (7.7%)
Site
Nipple	26 (0.3%)	15 (0.6%)	<.001
Upper-inner quadrant	2314 (24.2%)	373 (16.0%)
Lower-inner quadrant	920 (9.6%)	197 (8.4%)
Upper-outer quadrant	5188 (54.3%)	1446 (61.8%)
Lower-outer quadrant	1105 (11.6%)	307 (13.1%)
Histologic
Others	2082 (21.8%)	492 (21.0%)	.446
No special type	7471 (78.2%)	1846 (79.0%)
Grade
Grade I	3143 (32.9%)	511 (21.9%)	<.001
Grade II	4171 (43.7%)	1175 (50.3%)
Grade III	2239 (23.4%)	652 (27.9%)
Laterality
Left	4859 (50.9%)	1169 (50.0%)	.468
Right	4694 (49.1%)	1169 (50.0%)
T
T1	7675 (80.3%)	1382 (59.1%)	<.001
T2	1779 (18.6%)	893 (38.2%)
T3	99 (1.0%)	63 (2.7%)
Radiation
Yes	7999 (83.7%)	1967 (84.1%)	.661
No	1554 (16.3%)	371 (15.9%)
Chemotherapy
Yes	2423 (25.4%)	1232 (52.7%)	<.001
No	7130 (74.6%)	1106 (47.3%)
ER
Negative	8350 (87.4%)	2102 (89.9%)	.001
Positive	1203 (12.6%)	236 (10.1%)
PR
Negative	7445 (77.9%)	1926 (82.4%)	<.001
Positive	2108 (22.1%)	412 (17.6%)
HER2
Negative	1068 (11.2%)	276 (11.8%)	.413
Positive	8485 (88.8%)	2062 (88.2%)
Examined
1	3117 (32.6%)	551 (23.6%)	<.001
2	2837 (29.7%)	650 (27.8%)
3	1942 (20.3%)	543 (23.2%)
4	1044 (10.9%)	344 (14.7%)
5	613 (6.4%)	250 (10.7%)
Marital
Single	1314 (13.8%)	312 (13.3%)	.154
Married	5743 (60.1%)	1455 (62.2%)
SDW	2496 (26.1%)	571 (24.4%)

AI = American Indian/Alaska Native, API = Asian or Pacific Islander, SLN = sentinel lymph node.