Table 1 Demographic features of patients

Age (years)

 Mean ± SD

48.14 ± 11.586

Histology

 Ductal

83.2

 Lobular

9.8

 Mixed

4.8

 Missing data

2.2

Stage^a

 1 and 2

29.5

 3 and 4

18.8

 Missing data

51.7

Grade

 I

9.2

 II

38.1

 III

23.3

 Missing data

32.4

Clinical tumor size (cm)

 0

0.8

 < 2

34.4

 2.1–5

47.5

 > 5

17.2

 Missing data

32.4

Clinical lymph node

 0

14.2

 < 3

9.7

 4 and 9

12.5

 > 9

5.1

 Missing data

58.5

Her2 expression

 Positive

22.2

 2+

5.1

 Negative

42.6

 Missing data

30.1

ER expression

 Positive

47.2

 Negative

22.7

 Missing data

30.1

PR expression

 Positive

44.3

 Negative

25.6

 Missing data

30.1