Effects of interval between age at first pregnancy and age at diagnosis on breast cancer survival according to menopausal status: a register-based study in Korea

Table 1 Baseline characteristics at diagnosis among all breast cancer patients stratified by menopausal status

	All women		Premenopausal		Postmenopausal		p-value
	n	%	n	%	n	%	p-value
T stage							<0.001
T1,2	24051	82.9	17378	82.3	6673	84.9
T3,4	2235	17.1	1682	17.7	553	15.1
LN involvement							<0.001
(-)	17591	60.7	12714	60.2	4877	62.0
(+)	11398	39.3	8412	39.8	2986	38.0
ER							<0.001
(-)	10701	40.3	7527	39.3	3174	42.9
(+)	15829	59.7	11608	60.7	4221	57.1
HER2							0.026
(-)	18217	76.5	13263	76.9	4954	75.5
(+)	5605	23.5	3996	23.2	1609	24.5
Age at first pregnancy (years)							<.0001
Nulliparous	4943	19.08	4441	23.76	520	6.95
<20	520	2.01	202	1.08	318	4.41
20-24	6653	25.68	3756	20.10	2897	40.13
25-29	10923	42.16	8114	43.41	2809	38.91
≥30	2871	11.08	2178	11.65	693	9.60
Parity							<.0001
Nulliparous	4943	17.05	4441	21.02	502	6.38
1	3874	13.36	3095	14.65	779	9.91
2	13269	45.77	10458	49.50	2811	35.75
3	4345	14.99	2363	11.19	1982	25.21
4	1523	5.25	496	2.35	1027	13.06
≥5	1035	3.57	273	1.29	762	9.69

ISSN: 1472-6874