Table 4. Cox regression model for factors associated with breast cancer specific mortality in the Waikato, New Zealand 1999–2012.
| Characteristic | Univariate | Multivariate | Multivariate (Post 2005 cancers only) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| HR | 95% CI | p | HR | 95% CI | p | HR | 95% CI | p | ||
| Ethnicity a | ||||||||||
| NZ European | Ref | <0.001 | Ref | 0.088 | Ref | 0.226 | ||||
| Māori | 1.98 | 1.55–2.54 | 1.25 | 0.97–1.61 | 1.28 | 0.86–1.91 | ||||
| Year of diagnosis | ||||||||||
| 1999–2002 | Ref | 0.556 | Ref | 0.84 | - | |||||
| 2003–2006 | 1.13 | 1.19–1.43 | 1.11 | 0.85–1.45 | Ref | 0.793 | ||||
| 2007–2009 | 0.95 | 0.70–1.27 | 0.80 | 0.58–1.12 | 0.95 | 0.62–1.46 | ||||
| 2010–2012 | 0.97 | 0.66–1.41 | 0.77 | 0.51–1.16 | 0.84 | 0.50–1.41 | ||||
| Mode of detection | ||||||||||
| Non-screen | Ref | <0.001 | Ref | 0.031 | Ref | 0.029 | ||||
| Screen | 0.26 | 0.20–0.35 | 0.71 | 0.52–0.96 | 0.49 | 0.26–0.93 | ||||
| T stage | ||||||||||
| T1 | Ref | <0.001 | Ref | <0.001 | Ref | 0.001 | ||||
| T2 | 3.33 | 2.56–4.33 | 1.87 | 1.41–2.48 | 3.39 | 1.81–6.35 | ||||
| T3 | 8.68 | 6.01–12.5 | 3.13 | 2.10–4.66 | 4.51 | 2.04–9.95 | ||||
| T4 | 18.6 | 13.8–25.1 | 3.10 | 2.15–4.48 | 4.55 | 2.19–9.49 | ||||
| N stage | ||||||||||
| N0 | Ref | <0.001 | Ref | <0.001 | Ref | 0.002 | ||||
| N1 | 2.03 | 1.58–2.60 | 1.63 | 1.25–2.13 | 1.49 | 0.94–2.36 | ||||
| N2+ | 4.04 | 3.01–5.42 | 2.67 | 1.92–3.71 | 1.88 | 1.04–3.42 | ||||
| M Stage | ||||||||||
| M0 | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | ||||
| M1 | 15.4 | 12.2–19.4 | 3.60 | 2.61–4.96 | 4.21 | 2.63–6.73 | ||||
| Grade | ||||||||||
| I | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | ||||
| II | 4.93 | 2.90–8.38 | 3.01 | 1.76–5.17 | 3.94 | 1.39–11.2 | ||||
| III | 13.4 | 7.85–22.7 | 5.22 | 2.98–9.14 | 6.47 | 2.25–18.6 | ||||
| ER/PR | ||||||||||
| ER &/or PR + | Ref | <0.001 | Ref | <0.001 | Ref | 0.008 | ||||
| ER & PR - | 2.47 | 1.98–3.07 | 1.57 | 1.22–1.88 | 1.71 | 1.14–2.53 | ||||
| HER-2 | ||||||||||
| Negative | Ref | <0.001 | Ref | 0.157 | Ref | 0.386 | ||||
| Equivocal | 0.62 | 0.38–1.03 | 0.93 | 0.56–1.55 | 1.13 | 0.52–2.42 | ||||
| Positive | 1.80 | 1.39–2.33 | 0.93 | 0.71–1.22 | 0.76 | 0.49–1.16 | ||||
| Histology | ||||||||||
| Ductal | Ref | 0.293 | Ref | 0.139 | Ref | 0.458 | ||||
| Lobular | 0.87 | 0.62–1.22 | 0.83 | 0.57–1.21 | 0.85 | 0.46–1.56 | ||||
| Mixed | 0.91 | 0.45–1.83 | 1.29 | 0.62–2.65 | 0.84 | 0.32–2.17 | ||||
| Other | 0.58 | 0.32–1.05 | 0.73 | 0.39–1.36 | 0.47 | 0.21–1.04 | ||||
| Comorbidity score | ||||||||||
| 0 | Ref | <0.001 | Ref | 0.003 | Ref | 0.005 | ||||
| 1–2 | 2.05 | 1.64–2.56 | 1.49 | 1.17–1.90 | 1.90 | 1.28–2.82 | ||||
| 3+ | 2.48 | 1.32–4.67 | 1.24 | 0.64–2.37 | 1.65 | 0.67–4.07 | ||||
| Chemotherapy | ||||||||||
| No | Ref | 0.387 | Ref | 0.103 | Ref | 0.154 | ||||
| Yes | 1.09 | 0.89–1.34 | 0.81 | 0.62–1.64 | 0.72 | 0.46–1.13 | ||||
| Endocrine therapy | ||||||||||
| No | Ref | <0.001 | Ref | 0.019 | Ref | 0.057 | ||||
| Yes | 0.24 | 0.20–0.30 | 0.71 | 0.53–0.94 | 0.64 | 0.40–1.01 | ||||
HR—hazard ratios, 95% CI—95% confidence intervals,
a—adjusted for age and socio-economic deprivation.