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

Table 1 Clinicopathological features and tumor characteristics of patients

Item	Non-BCBM group (n = 136) [n (%)]	BCBM group (n = 68) [n (%)]	P
Age at diagnosis of BC (yr)			0.009
≤ 35	9 (6.6)	12 (17.6)
35-55	79 (58.1)	43 (63.2)
> 55	48 (35.3)	13 (19.2)
Menstrual status at diagnosis of BC			0.77
Premenopause	69 (50.7)	33 (48.5)
Menopause	67 (49.3)	35 (51.5)
Family history of cancer			0.12
None	112 (82.4)	60 (88.2)
Other malignancies	16 (11.8)	8 (11.8)
BC	8 (5.9)	0 (0.0)
Lymph node stage			0.01
N0	56 (41.2)	19 (27.9)
N1	43 (31.6)	14 (20.6)
N2	25 (18.4)	17 (25.0)
N3	12 (8.8)	15 (22.1)
Missing	0 (0.0)	3 (4.4)
Tumor size			0.17
T1	53 (39.0)	18 (26.5)
T2	67 (49.3)	37 (54.4)
T3	13 (9.6)	11 (16.2)
T4	1 (0.7)	0 (0.0)
Missing	2 (1.5)	2 (2.9)
Tumor stage at the initial diagnosis			< 0.001
IA	29 (21.3)	3 (4.4)
IIA	39 (28.7)	19 (27.9)
IIB	29 (21.3)	7 (10.3)
IIIA	22 (16.2)	17 (25.0)
IIIB	2 (1.5)	0 (0.0)
IIIC	11 (8.1)	11 (16.2)
IV	3 (2.2)	7 (10.3)
Missing	1 (0.7)	4 (5.9)
ER			0.009
Negative	42 (30.9)	32 (47.1)
Positive	94 (69.1)	32 (47.1)
Missing	0 (0.0)	4 (5.9)
PR			0.003
Negative	52 (38.2)	39 (57.4)
Positive	84 (61.8)	25 (36.8)
Missing	0 (0.0)	4 (5.9)
Molecular type			< 0.001
Luminal A type	71 (52.2)	13 (19.1)
Luminal B type	28 (20.6)	22 (32.4)
HER2-overexpressing type	18 (13.2)	14 (20.6)
Triple-negative type	19 (14.0)	14 (20.6)
Missing	0 (0.0)	5 (7.4)
Pathological type			0.42
Noninvasive carcinoma	10 (7.4)	2 (2.9)
Invasive ductal carcinoma	95 (69.9)	51 (75.0)
Invasive lobular carcinoma	5 (3.7)	2 (2.9)
Others	26 (19.1)	8 (11.8)
Missing	0 (0.0)	5 (7.4)
Metastasis
Bone metastasis			< 0.001
Yes	12 (8.8)	38 (55.9)
No	124 (91.2)	30 (44.1)
Liver metastasis			< 0.001
Yes	7 (5.1)	20 (29.4)
No	129 (94.9)	48 (70.6)
Lung metastasis			< 0.001
Yes	8 (5.9)	35 (51.5)
No	128 (94.1)	33 (48.5)
Number of liver, lung and bone metastases			< 0.001
0	123 (90.4)	21 (30.9)
1	8 (5.9)	19 (27.9)
2	3 (2.2)	18 (26.5)
3	2 (1.5)	10 (14.7)
Number of metastases to other sites			< 0.001
0	118 (86.8)	33 (48.5)
1	15 (11.0)	24 (35.3)
2	2 (1.5)	8 (11.8)
3	1 (0.7)	3 (4.4)
Surgical treatment			< 0.001
No	3 (2.2)	7 (10.3)
Breast-conserving surgery	20 (14.7)	5 (7.4)
Modified radical mastectomy	106 (77.9)	43 (63.2)
Others	7 (5.1)	13 (19.1)
Radiotherapy			0.006
No	76 (55.9)	24 (35.3)
Yes	60 (44.1)	44 (64.7)
Chemotherapy
Neoadjuvant chemotherapy			0.21
No	119 (87.5)	55 (80.9)
Yes	17 (12.5)	13 (19.1)
Anthracyclines			< 0.001
No	28 (20.6)	35 (51.5)
Yes	107 (78.7)	32 (47.1)
Missing	1 (0.7)	1 (1.5)
Taxane			0.35
No	35 (25.7)	22 (32.4)
Yes	101 (74.3)	46 (67.6)
HER2 targeted therapy			< 0.001
No	118 (86.8)	36 (52.9)
Yes	18 (13.2)	32 (47.1)

BC: Breast cancer; BCBM: Breast cancer brain metastasis; ER: Estrogen receptor; PR: Progesterone receptor; HER2: Human epidermal growth factor receptor 2.