Table 2. Baseline characteristics by breast cancer subtypes.

Characteristics	n	Luminal A		Luminal B		HER2		Triple-negative		P
		n	%	n	%	n	%	n	%
Age (years)
≤50	768	489	51.2	99	57.9	52	45.2	128	43.1	0.009
>50	770	466	48.8	72	42.1	63	54.8	169	56.9
Tumor size (cm)
≤2	822	543	57.0	75	43.9	66	57.9	138	46.5	0.001
>2	713	410	43.0	96	56.1	48	42.1	159	53.5
Unknown	3
Lymph nodes
Positive	633	395	42.0	73	42.9	48	42.1	117	40.1	0.927
Negative	884	546	58.0	97	57.1	66	57.9	175	59.9
Unknown	21
Adjuvant therapy
C	684	334	35.8	59	35.3	79	71.2	212	72.4	<0.001
C+E	579	431	46.2	85	50.9	23	20.7	40	13.7	<0.001
E	195	152	16.3	20	12.0	2	1.8	21	7.2	<0.001
No treatment	45	15	1.6	3	1.8	7	6.3	20	6.8	<0.001
Unavailable	35

C: chemotherapy; E: endocrine therapy; C+E: chemothrapy plus endocrine therapy.