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 |