Table IV.

Multivariate analysis of prognostic factors affecting overall survival of patients with BOM.

Variable	Hazard ratio	95% CI	P-value
HR status at breast cancer diagnosis
Negative	1.00	Reference	–
Positive	0.54	0.32-0.90	0.020
Number of metastases at BOM diagnosis
Multiple	1.00	Reference	–
Single	0.62	0.40-0.96	0.031
Location of bone metastasis at BOM diagnosis
Axial and appendicular	1.00	Reference	–
Axial	0.65	0.41-1.02	0.062
Appendicular	0.07	0.01-0.57	0.013

The factors with P<0.05 in the univariate analysis in Table II were incorporated into the multivariate analysis. Molecular subtype was adjusted for. BOM, bone-only metastases; HR, hormone receptor.