Table 3.
Cox proportional hazards model for subsequent survival in breast cancer patients with brain metastases.
| Variables | Univariate | Multivariate | ||
|---|---|---|---|---|
| HR (95% CI) | P value | HR (95% CI) | P value | |
| Age at breast cancer diagnosis | 1.005 (0.988–1.022) | .568 | ||
| ER status of primary breast lesion | 0.640 (0.443–0.925) | .018 | ||
| PR status of primary breast lesion | 0.621 (0.443–0.925) | .021 | ||
| HER2 status of primary breast lesion | 0.723 (0.491–1.065) | .100 | ||
| Triple-negative breast cancer | 2.461 (1.686–3.593) | <.001 | 2.320 (1.555–3.461) | <.001 |
| ECOG performance status at brain metastasis diagnosis | ||||
| 1 | Reference | <.001 | Reference | <.001 |
| 2 | 1.748 (1.138–2.688) | .011 | 1.485 (0.940–2.345) | .090 |
| 3 | 3.425 (2.079–5.650) | <.001 | 3.953 (2.335–6.692) | <.001 |
| Neurologic symptoms at brain metastasis diagnosis | 1.325 (0.810–2.167) | .263 | ||
| Histological grade of primary breast lesion | ||||
| 1 | Reference | <.001 | Reference | <.001 |
| 2 | 1.359 (0.674–2.740) | .392 | 1.725 (0.844–3.528) | .135 |
| 3 | 2.299 (1.527–3.460) | <.001 | 2.833 (1.844–4.354) | <.001 |
| Trastuzumab therapy | 0.622 (0.407–0.950) | .028 | ||
| Bone metastases | 1.527 (1.066–2.188) | .021 | ||
| Lung metastases | 1.429 (0.993–2.056) | .054 | ||
| Vertebral metastases | 1.205 (0.840–1.729) | .312 | ||
| Number of brain metastases | ||||
| 0 | Reference | .003 | ||
| 1 | 0.387 (0.201–0.746) | .005 | ||
| ≥2 | 0.743 (0.410–1.344) | .326 | ||
| Size of the most extensive lesion | 0.992 (0.980–1.005) | .213 | ||
| Location of brain metastases | ||||
| Supratentorial | Reference | <.001 | Reference | <.001 |
| Infratentorial | 1.359 (1.674–2.740) | .392 | 1.725 (0.844–3.528) | .135 |
| Both | 2.299 (1.527–3.460) | <.001 | 2.833 (1.844–4.354) | <.001 |
| Leptomeningeal seeding | 1.774 (1.114–2.826) | .016 | 1.692 (1.031–2.776) | .037 |
| γ-Knife radiosurgery | 0.530 (0.368–0.763) | .001 | ||
| WBRT | 1.045 (0.724–1.508) | .814 | ||
| Surgery | 0.434 (0.201–0.937) | .034 | ||
| Intrathecal chemotherapy | 1.164 (0.566–2.392) | .679 | ||
| Systemic chemotherapy after brain metastases | 0.364 (0.228–0.581) | <.001 | 0.332 (0.202–0.543) | <.001 |
| C-index | 0.761 | |||
| Akaike information criterion | 912.588 | |||
CI = confidence interval, ECOG = Eastern Cooperative Oncology Group, ER = estrogen receptor, HER2 = human epidermal growth factor receptor 2, HR = hazard ratio, PR = progesterone receptor, WBRT = Whole brain radiation therapy.