Table 1 Patient demographics, tumor characteristics, and intraoperative variables of invasive breast cancers (n = 353) in which a one SLN was identified versus two or more SLNs were identified.

Age (mean ± SD, years)

56 ± 11

56 ± 12

0.870

Height (mean ± SD, inches)

64 ± 3

64 ± 2

0.386

Weight (mean ± SD, pounds)

174 ± 45

165 ± 35

0.041

BMI (mean ± SD, kg/m²)

29.5 ± 6.9

28.3 ± 6.0

0.101

Breast size

0.053

   Small

6 (6%)

25 (10%)

   Medium

31 (30%)

101 (41%)

   Large

41 (39%)

83 (33%)

   Not available

26 (25%)

40 (16%)

Palpable tumor

53 (51%)

120 (48%)

0.635

Tumor location

0.259

   UOQ

51 (49%)

142 (57%)

   LOQ

21 (20%)

33(13%)

   UIQ

20 (19%)

38 (15%)

   LIQ

9 (9%)

21 (8%)

   Central

3 (3%)

15 (6%)

Type of diagnostic breast biopsy

0.301

   Core

79 (76%)

191 (77%)

   Excisional

24 (23%)

58 (23%)

   Fine needle aspiration

1 (1%)

0 (0%)

Pathologic T-stage

0.617

   T1

68 (65%)

176 (71%)

   T2

34 (33%)

69(28%)

   T3

2 (2%)

4 (2%)

Histopathology

0.958

   Ductal

90 (87%)

216 (87%)

   Lobular

3 (3%)

18 (7%)

   Mixed Ductal-Lobular

3 (3%)

9 (4%)

   Other

8 (8%)

6 (2%)

Histologic grade

0.032

   Well-differentiated

11 (11%)

56 (23%)

   Moderately-differentiated

47 (45%)

101 (41%)

   Poorly-differentiated

46 (44%)

92 (37%)

Estrogen receptor positive

77 (74%)

198 (80%)

0.258

Progesterone receptor positive

63 (61%)

165 (66%)

0.308

HER-2/neu positive

27 (26%)

46 (19%)

0.136

Lymphovascular invasion

24 (23%)

48 (19%)

0.419

Route of injection of ^{99 m}Tc-sulfur colloid

0.428

   Intradermal

33 (32%)

92 (37%)

   Intraparenchymal

38 (37%)

74 (30%)

   Subareolar

33 (32%)

83 (33%)

Surgery performed at time of SLN biopsy

0.184

   Lumpectomy

80 (77%)

169 (68%)

   Mastectomy

21 (20%)

74 (30%)

   SLN biopsy alone

3 (3%)

6 (2%)

Time from ^{99 m}Tc-sulfur colloid injection to SLN biopsy (mean ± SD, minutes)

290 ± 78

287 ± 66

0.682