Table 3 Standardized incidence ratio (SIR) of second invasive breast cancer (ipsilateral and contra lateral) after diagnosis of first in situ breast cancer, by year at first diagnosis, age at first diagnosis, time since first diagnosis and family history (years)

 1980–1984

81

3.3

2.6–4.1

72

3.1

2.4 − 3.9

9

6.6

3.0–12.5

 1985–1989

141

3.5

3.0 − 4.2

123

3.4

2.8–4.0

18

5.3

3.2–8.4

 1990–1994

292

5.2

4.6 − 5.9

259

5.1

4.5–5.8

33

5.9

4.1–8.3

 1995–1999

182

5.2

4.5 − 6.1

160

5.2

4.4–6.0

22

5.2

3.3–7.9

 2000–2004

72

5.1

4.0 − 6.4

63

5.1

3.9–6.5

9

5.5

2.5–10.4

P value

<0.001

1

  < 40

39

8.5

6.0–11.7

27

7.2

4.8–10.5

12

14.3

7.4–25.0

 40–49

173

4.9

4.2–5.7

147

4.8

4.1–5.71

26

4.7

3.1–6.8

 50–59

221

4.1

3.6–4.6

189

3.9

3.4–4.5

32

5.2

3.6–7.4

 60–69

220

4.6

4.0–5.2

207

4.5

(4.0–5.2)

13

5.2

2.8–8.8

  ≥ 70

115

4.3

3.6–5.2

107

4.2

(3.4–5.1)

8

6.9

3.0–13.6

P trend

0.069

0.096

  < 40

39

8.5

6.1–11.7

27

7.2

4.8–10.5

12

14.3

7.4–25.0

  > 40

729

4.4

4.1–4.8

650

4.3

4.0–4.7

79

5.2

4.1–6.4

P value

0.012

0.001

 0–4

401

5.2

4.7–5.7

359

5.1

4.6–5.7

42

5.5

3.9–7.3

 5–9

230

4.4

3.9–5.1

197

4.2

3.6–4.8

33

6.5

4.5–9.2

 10–14

96

3.4

2.8–4.2

85

3.3

2.6–4.1

11

4.3

2.1–7.7

  > 15

41

3.4

2.4–4.6

36

3.2

2.2–4.4

5

5.9

1.9–13.8

P trend

<0.001

0.848