Table 3. Multivariate analysis of prognostic factors among ER positive patients with pure IDC and IDC-DCIS.

Characteristics	BCSS				OS
	HR	95% CI	P		HR	95% CI	P
Year of diagnosis	0.978	0.967–0.990	<0.001		0.968	0.961–0.974	<0.001
Age
≤60 vs. >60 years	0.668	0.627–0.711	<0.001		0.312	0.299–0.326	<0.001
Race			<0.001				<0.001
Black vs. White	1.375	1.244–1.519	<0.001		1.326	1.241–1.416	<0.001
Asian or Indian vs. White	0.746	0.646–0.861	<0.001		0.666	0.607–0.731	<0.001
Histologic grade			<0.001				<0.001
I vs. III	0.234	0.208–0.264	<0.001		0.556	0.527–0.586	<0.001
II vs. III	0.533	0.501–0.568	<0.001		0.706	0.678–0.736	<0.001
T stage			<0.001				<0.001
T1 vs. T4	0.185	0.158–0.216	<0.001		0.226	0.201–0.255	<0.001
T2 vs. T4	0.433	0.374–0.501	<0.001		0.402	0.357–0.452	<0.001
T3 vs. T4	0.699	0.593–0.824	<0.001		0.653	0.569–0.750	<0.001
N stage			<0.001				<0.001
N0 vs. N3	0.192	0.168–0.218	<0.001		0.258	0.232–0.288	<0.001
N1 vs. N3	0.354	0.313–0.400	<0.001		0.351	0.315–0.391	<0.001
N2 vs. N3	0.596	0.522–0.681	<0.001		0.596	0.529–0.671	<0.001
Existence of DCIS component
IDC-DCIS vs. pure IDC	0.924	0.873–0.978	0.006		0.919	0.888–0.951	<0.001
Surgery
BCS vs. mastectomy	0.858	0.798–0.923	<0.001		1.117	1.069–1.167	<0.001
Radiation
Yes vs. none or unknown	0.699	0.653–0.748	<0.001		0.486	0.467–0.507	<0.001
Chemotherapy
Yes vs. none or unknown	0.794	0.738–0.853	<0.001		0.533	0.508–0.559	<0.001
PR status
Positive vs. negative	0.653	0.607–0.702	<0.001		0.813	0.775–0.853	<0.001

IDC, invasive ductal breast cancer; DCIS, ductal carcinoma in situ; BCSS, breast cancer-specific survival; OS, overall survival; HR, hazard ratio; CI, confidence interval.