Analysis of clinicopathological features and prognostic factors of breast cancer brain metastasis

Table 2 High-risk factors of breast cancer brain metastasis

Item	Univariate Cox		Multivariate Cox
	HR (95%CI)	P	HR (95%CI)	P
Age at diagnosis of BC (yr)
≤ 35	Reference
> 35	0.008 (0-1.89)	0.083
Menstrual status at diagnosis of BC
Premenopause	Reference
Menopause	1.29 (0.52-3.20)	0.59
Family history of cancer
None	Reference
Yes	0.62 (0.26-1.44)	0.26
Lymph node stage
N0-N1	Reference
N2-N3	2.77 (1.40-5.48)	0.004	NS
Tumor size
T1-T2	Reference
T3-T4	1.44 (0.65-3.15)	0.37
Tumor stage at the initial diagnosis
I-II	Reference
III-IV	3.84 (1.89-7.78)	< 0.001	5.58 (1.99-15.68)	0.001
ER
Negative	Reference
Positive	0.49 (0.27-0.87)	0.015	NS
PR
Negative	Reference
Positive	0.36 (0.18-0.69)	0.002	NS
Molecular type
Luminal A type	Reference
Luminal B type	3.95 (1.71-9.14)	0.001	5.36 (1.61-17.76)	0.006
HER2-overexpression type	4.01 (1.61-9.96)	0.003	5.0 (1.30-19.25)	0.019
Triple-negative type	4.34 (1.55-12.11)	0.005	NS	NS
Pathological type
Others	Reference
Invasive ductal carcinoma	1.83 (0.83-4.05)	0.14
Invasive lobular carcinoma	1.31 (0.22-7.69)	0. 77
Surgical treatment
Others	Reference
Modified radical mastectomy	0.48 (0.26-0.90)	0.021	NS
Bone metastasis
No	Reference
Yes	7.19 (3.13-16.52)	< 0.001	NS
Liver metastasis
No	Reference
Yes	7.44 (2.77-20.01)	< 0.001	NS
Lung metastasis
No	Reference
Yes	15.87 (5.61-44.89)	< 0.001	24.18 (6.40-91.43)	< 0.001
Number of liver, lung and bone metastases
< 2	Reference
≥ 2	17.78 (5.38-58.73)	< 0.001	NS
Number of metastases to other sites
< 2	Reference
≥ 2	7.33 (2.05-26.27)	0.002	NS

95%CI: 95% confidence interval; NS: Not statistically significant; HR: Hazard ratio; ER: Estrogen receptor; PR: Progesterone receptor; BC: Breast Cancer; HER2: Human epidermal growth factor receptor 2.