Table 1. Clinicopathologic characteristics of study population by age.

	80–84 years		85–89 years		90+ years		Total
	n=310	%	n=92	%	n=27	%	n=429	%
Histology
Ductal carcinoma in situ	51	16.5	7	7.6	2	7.4	60	14.0
Invasive ductal	196	63.2	69	75.0	20	74.1	285	66.4
Invasive lobular	45	14.5	13	14.1	4	14.8	62	14.5
Invasive mammary	7	2.3	2	2.2	0	0.0	9	2.1
Other	11	3.5	1	1.1	1	3.7	13	3.0
Extent of Disease
T stage
T1S	51	16.5	7	7.6	2	7.4	60	14.0
T1	195	62.9	58	63.0	16	59.3	269	62.7
T2	51	16.5	23	25.0	8	29.6	82	19.1
T3/4	11	3.5	4	4.3	1	3.7	16	3.7
T0/Tx	2	0.6	-	-	-	-	2	0.5
Pathologic Nodal Status
Negative	159	51.3	46	50.0	9	33.3	214	49.9
Positive	90	29.0	28	30.4	7	25.9	125	29.1
No surgical staging	61	19.7	18	19.6	11	40.7	90	21.0
Estrogen Receptor Status*	n=259		n=85		n=25		n=369
Positive	218	84.2	71	83.5	20	80.0	309	83.7
Negative	39	15.1	14	16.5	5	20.0	58	15.7
Unknown	2	0.8	0	0.0	0	0.0	2	0.5
HER2 Receptor Status*	n=259		n=85		n=25		n=369
Positive	10	3.9	11	12.9	2	8.0	23	6.2
Negative	240	92.7	67	78.8	23	92.0	330	89.4
Unknown	8	3.1	7	8.2	0	0.0	15	4.1
Equivocal	1	0.4					1	0.3

^*invasive cases only