Table 2. Comparison of clinicopathological characteristics between first tumor and second tumor of the BiBC group.

Characteristics	First tumor of BiBC	Second tumor of BiBC	P value
Median Age (years) (range)	47.5 (27 ~ 69)	50 (29 ~ 70)	0.311
Nodal status
N0	12 (25.0%)	23 (47.9%)	0.179
N1	12 (25.0%)	8 (16.7%)
N2	11 (22.9%)	5 (10.4%)
N3	13 (27.1%)	12 (25.0%)
TNM stage
I	3 (6.3%)	10 (20.8%)	0.114
II	14 (29.2%)	15 (31.3%)
III	31 (64.5%)	23 (47.9%)
Histologic type
Infiltrating Duct Carcinoma	35 (73.0%)	33 (68.8%)	0.887
Infiltrating Lobular Carcinoma	5 (10.4%)	8 (16.7%)
Others	8 (16.7%)	7 (14.6%)
ER status
Positive	28 (58.6%)	32 (66.7%)	0.453
Negative	20 (41.4%)	16 (33.3%)
PR status
Positive	25 (52.0%)	21 (43.8%)	0.559
Negative	23 (47.9%)	27 (56.3%)
HER-2 status
Positive	15 (31.3%)	18 (37.5%)	0.548
Negative	33 (68.8%)	30 (62.5%)