Safety and Efficacy of Long-Term Zoledronic Acid in Advanced Breast Cancer with Bone Metastasis in South China

Table 6

Cox regression analysis of breast cancer with bone metastasis following ZA treatment.

Parameter		Univariate			Multivariate
		HR	95% CI	value	HR	95% CI	value
Age	<50 years
	≥50 years	0.980	(0.756, 1.270)	0.876
Menstrual status	Perimenopausal
	Postmenopausal	0.884	(0.685, 1.141)	0.345
ER	Negative
	Positive	1.057	(0.766, 1.459)	0.734
PR	Negative
	Positive	1.038	(0.773, 1.393)	0.805
HER2	Negative
	Positive	1.106	(0.869, 1.408)	0.414
Molecular type	Luminal A/B1
	Luminal B2	1.141	(0.832, 1.565)	0.412
	HER2+	1.019	(0.637, 1.629)	0.939
	Triple negative	1.055	(0.629, 1.770)	0.839
Tumor size	T1–T2
	T3–T4	0.936	(0.692, 1.267)	0.670
Lymph node	N0
	N1–N3	1.147	(0.856, 1.539)	0.359
Performance status	0–1
	≥2	2.054	(1.534, 2.750)	<0.001	2.073	(1.539, 2.793)	<0.001
No. of involved bones	1–3 bones
	>3 bones	1.309	(1.014, 1.689)	0.038	1.209	(0.913, 1.603)	0.186
Involved bones	Non-load-bearing bone
	Load-bearing bone	1.305	(0.879, 1.937)	0.187	1.111	(0.722, 1.711)	0.632
Stage of bone metastases	Primary
	Subsequent	1.159	(0.822, 1.633)	0.400
Other organ metastasis	Visceral organ
	Nonvisceral organ	1.407	(1.087, 1.820)	0.009	1.513	(1.163, 1.968)	0.002
Time from BC to BM group	<32 months
	≥32 months	0.832	(0.645, 1.072)	0.154	0.971	(0.726, 1.298)	0.842
ZOL group	∼24 months
	>24 months	0.868	(0.662, 1.138)	0.305

ER: estrogen receptor, PR: progesterone receptor, ZA: zoledronic acid, and HR: hazard ratio. Backward stepwise (conditional LR) was selected for multivariate Cox regression analysis.