Table 2.
Univariate and multivariate predictors of survival after surgery in 87 patients with breast cancer metastases to the spine
| Variable | Univariate analysis | Multivariate analysis | |||||
|---|---|---|---|---|---|---|---|
| Rate ratioa | 95% CI | P value | Median survival (mo) | Rate ratioa | 95% CI | P value | |
| Age | |||||||
| <65b | 1.0 | – | – | 17.9 | |||
| ≥65 | 0.6 | 0.2–1.6 | 0.30 | 42.7c | NI | ||
| Interval from breast cancer diagnosis to first spinal metastasis (months) | |||||||
| ≥60b | 1.0 | – | – | 28.0 | |||
| 12–60 | 1.2 | 0.6–2.5 | 0.68 | 21.5 | NI | ||
| <12 | 1.5 | 0.6–4.0 | 0.39 | 11.8 | |||
| Tumor histology | |||||||
| Ductal carcinomab | 1.0 | – | – | 21.1 | |||
| Adenocarcinoma | 1.4 | 0.7–2.8 | 0.32 | 21.3 | NI | ||
| Lymph node status | |||||||
| Negativeb | 1.0 | – | – | 28.0 | |||
| Positive | 1.4 | 0.7–2.9 | 0.33 | 17.2 | NI | ||
| Preop Frankel grade | |||||||
| Ambulatory Eb | 1.0 | – | – | 21.1 | |||
| Ambulatory D | 1.2 | 0.6–2.1 | 0.63 | 21.5 | NI | ||
| Non-ambulatory (A-C) | 1.3 | 0.5–3.5 | 0.56 | 3.1 | |||
| Extent of metastatic disease | |||||||
| Spine onlyb | 1.0 | – | – | 28.0 | |||
| Spine plus Visceral | 1.4 | 0.7–3.0 | 0.32 | 17.4 | NI | ||
| Spine plus Non-visceral | 1.5 | 0.8–2.9 | 0.26 | 17.2 | |||
| Preoperative radiation to operative site | |||||||
| Nob | 1.0 | – | – | 17.4 | NI | ||
| Yes | 0.7 | 0.4–1.3 | 0.25 | 21.5 | |||
| Surgical approach | |||||||
| Single (anterior or posterior)b | 1.0 | – | – | 17.9 | NI | ||
| Combined | 0.8 | 0.4–1.7 | 0.63 | 25.1 | |||
| Number of vertebral bodies removed | |||||||
| Noneb | 1.0 | – | – | 16.2 | |||
| One | 0.9 | 0.4–1.7 | 0.64 | 21.3 | NI | ||
| Two or more | 1.1 | 0.5–2.4 | 0.79 | 21.5 | |||
| Number of spine lesions by MRI | |||||||
| 1b | 1.0 | – | – | 22.9 | |||
| 2 | 1.7 | 0.8–3.6 | 0.14 | 17.0 | NS | ||
| 3 or more | 1.5 | 0.7–2.9 | 0.26 | 16.5 | |||
| Major postoperative complications | |||||||
| Nob | 1.0 | – | – | 22.9 | |||
| Yes | 1.7 | 0.8–3.5 | 0.13 | 11.1 | NS | ||
| Spine tumor location | |||||||
| Non-cervicalb | 1.0 | – | – | 25.1 | 1.0 | − | − |
| Cervical | 2.3 | 1.3–4.2 | 0.006 | 6.8 | 2.1 | 1.0–4.5 | 0.06 |
| Estrogen receptor | |||||||
| Positiveb | 1.0 | – | – | 30.0 | 1.0 | − | − |
| Negative | 3.4 | 1.6–7.1 | 0.001 | 11.0 | 3.7 | 1.7–8.1 | 0.001 |
| Progesterone receptor | |||||||
| Positiveb | 1.0 | – | – | 30.0 | |||
| Negative | 2.6 | 1.3–5.3 | 0.007 | 11.0 | NS | ||
CI confidence interval, NI not included, NS not significant
Bold values represent variables that showed statistical significance (or close to it) during the univariate and multivariate analysis
aRate ratio > 1.0 indicates a faster rate of death, <1.0 indicates a slower rate of death, rate ratio of 1.0 indicates a similar rate of death. Cox proportional Hazard analysis used
bReferent group (group that others are compared to)
cMean; median not reached