Table 4 False-negative rate of axillary ultrasound (AUS) depending on extension of nodal involvement (n = 166)

Nodal metastasis size *

<0.001

≤5 mm

41

4

37

90.2

5.1-10 mm

46

19

27

58.7

>10 mm

76

55

21

27.6

Number of metastatic involved lymph nodes

<0.001

N1 (1–3)

86

27

59

68.6

N2 (4–9)

48

28

20

41.7

N3 (≥10)

32

24

8

25.0

Capsular infiltration

<0.001

No

83

23

60

72.3

Yes

83

56

27

32.5