Table 3.
Cox proportional hazards regression model of breast cancer-specific survival
| Variable | Univariate analysis
|
Multivariate analysis
|
||
|---|---|---|---|---|
| HR (95% CI) | P-value | HR (95% CI) | P-value | |
| Age (years) | ||||
| ≤50 | Reference | Reference | ||
| >50 | 1.86 (1.51–2.30) | <0.001 | 1.83 (1.12–2.97) | 0.015 |
| Year of diagnosis | ||||
| 1998–2002 | Reference | Reference | ||
| 2003–2007 | 0.85 (0.71–1.03) | 0.096 | 0.62 (0.39–0.99) | 0.046 |
| Race | ||||
| Black | Reference | Reference | ||
| White | 0.49 (0.40–0.61) | <0.001 | 0.51 (0.32–0.81) | 0.004 |
| Other* | 0.35 (0.24–0.51) | <0.001 | 0.50 (0.22–1.13) | 0.096 |
| Marital status | ||||
| Non-married† | Reference | Reference | ||
| Married | 0.61 (0.52–0.72) | <0.001 | 0.52 (0.36–0.75) | <0.001 |
| Poverty–high school index | ||||
| Low SEP | Reference | Reference | ||
| Middle SEP | 0.99 (0.81–1.20) | 0.883 | 1.35 (0.85–2.13) | 0.204 |
| High SEP | 0.64 (0.50–0.81) | <0.001 | 0.58 (0.31–1.06) | 0.077 |
| Laterality | ||||
| Left | Reference | Reference | ||
| Right | 0.89 (0.75–1.04) | 0.139 | 0.67 (0.46–0.97) | 0.033 |
| Primary site | ||||
| Single-quadrant lesions | Reference | Reference | ||
| Multi-quadrant lesions | 1.27 (1.04–1.56) | 0.020 | 1.07 (0.63–1.82) | 0.800 |
| ER status | ||||
| Negative/borderline | Reference | Reference | ||
| Positive | 0.60 (0.42–0.86) | 0.006 | 0.99 (0.56–1.74) | 0.961 |
| PR status | ||||
| Negative/borderline | Reference | Reference | ||
| Positive | 0.59 (0.43–0.83) | 0.002 | 0.69 (0.42–1.12) | 0.136 |
| Grade | ||||
| I | Reference | Reference | ||
| II | 1.17 (0.86–1.58) | 0.316 | 1.82 (0.92–3.59) | 0.086 |
| III and IV | 1.34 (1.00–1.80) | 0.053 | 1.73 (0.86–3.47) | 0.122 |
| RT | ||||
| No | Reference | Reference | ||
| Yes | 0.85 (0.72–1.00) | 0.049 | 0.71 (0.48–1.03) | 0.073 |
Notes:
*
Including American Indian/Alaskan Native and Asian/Pacific Islander.
†
Including divorced, widowed, single (never married), and separated.
Abbreviations: HR, hazard ratio; CI, confidence interval; SEP, socioeconomic position; ER, estrogen receptor; PR, progesterone receptor; RT, radiotherapy.