Table 2 Relationship between training set characteristics and NSLNM

Age (median [IQR])

1 (0.98–1.02)

Position (%)

 Left

1

 Right

1.03 (0.75–1.41)

BMI (%)

 < 18.5

1

 18.5–23.9

0.59 (0.22–1.61)

 24–27.9

0.77 (0.28–2.11)

 ≥ 28

0.95 (0.34–2.62)

Pregnant (%)

 0

1

 1

1.02 (0.48–2.17)

 ≥ 2

0.85 (0.39–1.87)

Menopause (%)

 No

1

 Yes

1.1 (0.81–1.51)

Nipple retraction (%)

 No

1

 Yes

1.41 (0.7–2.84)

Nipple discharge (%)

 No

1

 Yes

0.45 (0.13–1.59)

Number of tumor (%)

 Single focal

1

 Multi-focal

1.51 (0.92–2.49)

cT (%)

 1

1

 2

1.31 (0.95–1.81)

 3

1.04 (0.35–3.07)

 4

2.29 (0.32–16.49)

Aspect ratio (%)

 < 1

1

 > 1

1.35 (0.7–2.59)

 = 1

1.26 (0.41–3.91)

US tumor borderline (%)

 Clear

1

 Lack of clarity

1.46 (0.79–2.68)

 Blurring

1.46 (0.84–2.56)

US tumor form (%)

 Rule

1

 Underrule

0.82 (0.3–2.26)

 Irregularity

1.45 (0.71–2.94)

US tumor blood (%)

 No

1

 Yes

1.03 (0.69–1.54)

cN

 cN0

1

 cN1/cN2/cN3

1.5 (1.07–2.09)

1.22 (0.86–1.74)

US BI-RADS (%)

 3

1

 4

2.02 (0.57–7.18)

 5

3.4 (0.92–12.57)

 6

2.89 (0.32–25.7)

MG calcification (%)

 No

1

 Yes

1.15 (0.8–1.65)

MG BI-RADS (%)

 3

1

 4

1.77 (1.02–3.05)

1.68 (0.95–2.97)

 5

1.88 (0.97–3.66)

1.92 (0.96–3.86)

 6

1.03 (0.36–2.95)

0.9 (0.3-2.7)

SLNs group (%)

 Negative

1

 Positive

2.38 (1.3–4.36)

1.64 (0.88–3.05)

Ratio of no. of positive SLNs to total no. of SLNs (%)

 ≤ 0.5

1

 > 0.5

3.82 (2.69–5.43)

3.51 (2.43–5.05)