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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

From: Breast implants following mastectomy in women with early-stage breast cancer: prevalence and impact on survival

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
  1. aAdjusted for age, year, stage at diagnosis, race/ethnicity, SEER region, tumor grade, histology, and radiation therapy.
  2. bModel (n = 689) restricted to women with implant-specific information and concordant bilateral implants