Table 1 Baseline demographic and clinicopathologic features of the mammary NEC cohort and the invasive mammary carcinoma control cohort from the SEER database (2003–2009)

Age, years, mean ± SD

63.6 ± 14.9

61.3 ± 14.2

0.029

Tumor size (mm), mean ± SD

31.9 ± 31.1

22.5 ± 24.1

<0.0001

No. of patients

%

No. of patients

%

Sex

0.06^a

 Male

3

2.1

2,909

0.8

 Female

139

97.9

378,735

99.2

Race

NS

 White

121

85.2

312,513

81.9

 Black

13

9.2

38,975

10.2

 Other

8

5.6

30,156

7.9

AJCC TNM stage

<0.0001*

 I

32

22.5

173,349

45.4

 II

52

36.6

125,129

32.8

 III

16

11.3

42,020

11.0

 IV

34

23.9

18,844

4.9

 Unknown

8

5.6

22,302

5.8

Regional lymph node

0.05*

 Negative

52

36.6

214,745

56.3

 Positive

40

28.2

109,741

28.8

 Unknown

50

35.2

57,158

14.9

Grade

<0.0001*

 I

17

12.0

75,043

19.7

 II

30

21.1

147,540

38.7

 III

60

42.3

126,919

33.3

 Unknown

35

24.7

32,142

8.3

ER status

0.003**

 Negative

37

26.1

74,093

19.4

 Borderline

0

0

812

0.2

 Positive

77

54.2

274,474

71.9

 Unknown

28

19.7

32,265

8.5

PR status

<0.0001**

 Negative

59

41.6

114,069

29.9

 Borderline

0

0

2,626

0.7

 Positive

53

37.3

228,877

60.0

 Unknown

30

21.1

36,214

9.5

Surgery

<.0001*

 No

33

23.2

28,888

7.6

 Yes

109

76.8

352,865

92.4

Radiation

0.038

 No

91

64.1

211,458

55.4

 Yes

51

35.9

170,186

44.6