Table 4

Proportional hazards regression model: hazard ratio and 95% confidence interval (CI) for mastectomy-treated breast cancer patients in the Surveillance, Epidemiology, and End Results (SEER) Breast Implant Surveillance Study, 1983–1989 (n = 4385)a

Covariate
Distribution of sample
Breast cancer mortality
Non-breast cancer mortality



n
%
Hazard ratio
95% confidence interval
Hazard ratio
95% confidence interval

Implant status






     No (referent)
3568
81.4
1.00
-
1.00
-
     Yes
817
18.6
0.54
0.43–0.67
0.59
0.41–0.85
Age at diagnosis






     < 35 years
163
3.7
1.95
1.42–2.69
0.24
0.09–0.66
     35–44 years
805
18.4
1.29
1.07–1.56
0.19
0.12–0.30
     45–54 years
1332
30.4
1.02
0.86–1.20
0.35
0.26–0.46
     55–64 years (referent)
2085
47.6
1.00
-
-
-
Race/ethnicity






     Non-Hispanic White (referent)
3915
89.3
1.00
-
1.00
-
     Non-Hispanic Black
131
3.0
0.90
0.58–1.39
1.58
0.93–2.68
     Hispanic
120
2.7
1.37
0.93–2.04
1.22
0.64–2.33
     Non-Hispanic Asian
160
3.7
0.86
0.57–1.31
0.68
0.33–1.39
     Other/unknown
59
1.4
0.75
0.37–1.50
1.36
0.60–3.07
Stage at diagnosis






     Local (referent)
3126
71.3
1.00
-
1.00
-
     Regional
1208
27.6
2.28
1.97–2.63
1.86
1.65–2.09
     Unstaged
51
1.2
3.80
2.41–5.99
3.35
2.28–4.92
SEER region






     San Francisco–Oakland (referent)
1624
37.0
1.00
-
1.00
-
     Seattle–Puget Sound
1423
34.1
1.10
0.91–1.32
1.17
0.91–1.51
     Iowa
1268
28.9
1.15
0.96–1.38
0.86
0.66–1.13
Year of diagnosis






     1983 (referent)
1037
23.7
1.00
-
1.00
-
     1985
1003
22.9
1.06
0.88–1.29
0.96
0.73–1.27
     1987
1232
28.1
0.97
0.80–1.18
1.05
0.78–1.40
     1989
1113
25.4
0.84
0.68–1.04
1.12
0.80–1.56
Grade






     Well differentiated (referent)
142
3.2
1.00
-
1.00
-
     Moderately differentiated
695
15.9
2.16
1.13–4.13
0.75
0.42–1.34
     Poorly differentiated
817
18.6
3.45
1.82–6.53
0.79
0.44–1.40
     Undifferentiated
182
4.2
4.97
2.52–9.78
1.23
0.60–2.52
     Unknown
2549
58.1
2.41
1.28–4.52
0.85
0.50–1.45
Histology






     Ductal (referent)
3253
74.2
1.00
-
1.00
-
     Lobular
279
6.4
1.09
0.82–1.44
1.26
0.88–1.81
     Mixed ductal and lobular
167
3.8
1.06
0.74–1.53
0.66
0.32–1.33
     Other
686
15.6
0.71
0.57–0.89
1.01
0.76–1.34
Radiation therapy






     No (referent)
4047
92.3
1.00
-
1.00
-
     Yes
329
7.5
1.43
1.15–1.78
0.84
0.54–1.30
     Unknown
9
0.2
4.68
1.74–12.60
-
-
Type of breast implantb






     Silicone gel (referent)
274
39.8
1.00
-
1.00
-
     Saline
118
17.1
1.01
0.44–2.34
1.75
0.29–10.39
     Double lumen
240
34.8
1.49
0.83–2.70
3.13
0.91–10.78
     Other
26
3.8
1.11
0.24–5.03
-
-
     Unknown
31
4.5
2.03
0.71–5.79
6.59
1.17–37.06

aAdjusted for age, year, stage at diagnosis, race/ethnicity, SEER region, tumor grade, histology, and radiation therapy.

bModel (n = 689) restricted to women with implant-specific information and concordant bilateral implants

Le et al. Breast Cancer Res 2005 7:R184   doi:10.1186/bcr974