Table 2 Basic data of variables in OBC patients with breast-conserving therapy (BCT) and mastectomy

N

748

100

422

100

Age

  <   0.001

 <   40

24

3.21

29

6.87

 40–49

91

12.17

83

19.67

 50–59

216

28.88

126

29.86

 60–69

223

29.81

114

27.01

 ≥ 70

194

25.94

70

16.59

 Mean (± SD)

61.16 ± 11.35

57.65 ± 11.72

  <   0.001*

Race

0.14**

 White

587

78.48

340

80.57

 Black

92

12.30

45

10.66

 Asian or Pacific Islander

57

7.62

36

8.53

 American Indian/Alaska Native

9

1.20

0

0

 Unknown/other

3

0.40

1

0.24

Marital status

0.64

 Not married

289

34.17

153

36.3

 Married

433

61.67

256

60.7

 Unknown

26

4.17

13

3.1

Grade

0.30

 I/II

35

4.68

28

6.64

 III

135

18.05

85

20.14

 IV

7

0.94

2

0.47

 Unknown

571

76.34

307

72.75

Laterality

0.15

 Right

342

45.72

212

50.24

 Left

406

54.28

210

49.76

Histology

0.04

 Ductal carcinoma

277

37.03

192

45.50

 Lobular carcinoma

37

4.95

16

3.79

 Mixed type

16

2.14

9

2.13

 Other

418

55.88

205

48.58

N

  <   0.001

 N1mi

12

1.60

19

4.50

 N1

481

64.30

226

53.55

 N2

131

17.51

95

22.51

 N3

124

16.58

82

19.43

No. of examined LN

  <   0.001

 1–3

131

17.51

49

11.61

 4–9

100

13.37

72

17.06

 ≥ 10

390

52.14

276

65.40

 Other/Unknown

127

16.98

25

5.92

No. of positive LN

  <   0.001

 1–3

376

50.27

227

53.79

 4–9

117

15.64

93

22.04

 ≥ 10

86

11.50

60

14.22

 Other/Unknown

169

22.59

42

9.95

Stage

  <   0.001

 IB

12

1.60

19

4.50

 IIA

481

64.30

226

53.55

 IIIA

131

17.51

96

22.75

 IIIC

124

16.58

81

19.19

Radiation

  <   0.001

 Yes

462

61.76

215

50.95

 None/Unknown

286

38.24

207

49.05

Chemotherapy

0.003

 Yes

566

75.67

351

83.18

 No/Unknown

182

24.33

71

16.82

Type of systemic therapy

  <   0.001

 Neoadjuvant

61

8.16

55

13.03

 Adjuvant

380

50.80

196

46.45

 Neoadjuvant + adjuvant

49

6.55

54

12.80

 Only systemic therapy, no surgery

28

3.74

0

0

 Other

113

15.11

74

17.54

 No/Unknown

117

15.64

43

10.19

Subtypes

0.48

 Luminal A

214

28.61

106

25.12

 Luminal B

65

8.69

44

10.43

 HER2 + 

51

6.82

23

5.45

 Triple negative

93

12.43

52

12.32

 Unknown

325

43.45

197

46.68

ER

0.89

 Negative

259

34.63

149

35.31

 Borderline/Unknown

61

8.16

37

8.77

 Positive

428

57.22

236

55.92

PR

0.76

 Negative

372

49.73

215

50.95

 Borderline/Unknown

77

10.29

47

11.14

 Positive

299

39.97

160

37.91

HER2

0.44

 Negative

307

41.04

158

37.44

 Positive

118

15.78

67

15.88

 Unknown

323

43.18

197

46.68