Table 1.

Baseline characteristics of sPR+ patients included from the SEER database

Characteristic		All Patients		HER2+		HER2-		P value
		N=3467	%	N=1050	30.29%	N=2417	69.71%	(HER2+ vs HER2-)
Age at diagnosis	<40	390	11.25%	115	10.95%	275	11.38%	0.076
	40-49	727	20.97%	212	20.19%	515	21.31%
	50-59	926	26.71%	313	29.81%	613	25.36%
	60-69	776	22.38%	227	21.62%	549	22.71%
	70-79	405	11.68%	123	11.71%	282	11.67%
	80+	243	7.01%	60	5.71%	183	7.57%
Race	White	2534	73.09%	751	71.52%	1783	73.77%	<0.001
	Black	516	14.88%	118	11.24%	398	16.47%
	Other	318	9.17%	169	16.10%	212	8.77%
	Unknown	36	1.04%	12	1.14%	24	0.99%
Histological type	IDC	3038	87.63%	942	89.71%	2096	86.72%	0.016
	Non-IDC	429	12.37%	108	10.29%	321	13.28%
Marital	Married	1933	55.75%	601	57.24%	1332	55.11%	0.511
	Unmarried	1339	38.62%	392	37.33%	947	39.18%
	Unknown	195	5.62%	57	5.43%	138	5.71%
T Stage	T1	1404	40.50%	402	38.29%	1002	41.46%	<0.001
	T2	1486	42.86%	422	40.19%	1064	44.02%
	T3	278	8.02%	108	10.29%	170	7.03%
	T4	183	5.28%	68	6.48%	115	4.76%
	Tx	116	3.35%	50	4.76%	66	2.73%
N Stage	N0	2204	63.57%	573	54.57%	1631	67.48%	<0.001
	N1	943	27.20%	359	34.19%	584	24.16%
	N2	156	4.50%	57	5.43%	99	4.10%
	N3	121	3.49%	45	4.29%	76	3.14%
	Nx	43	1.24%	16	1.52%	27	1.12%
Grade	I	77	2.22%	12	1.14%	65	2.69%	<0.001
	II	639	18.43%	252	24.00%	387	16.01%
	III/IV	2583	74.50%	716	68.19%	1867	77.24%
	Unknown	168	4.85%	70	6.67%	98	4.05%
Median household income (inflation ajusted)	<50,000 $	513	14.80%	164	15.62%	349	14.44%	0.161
	50,000-59,999 $	569	16.41%	171	16.29%	398	16.47%
	60,000-69,999 $	1152	33.23%	322	30.67%	830	34.34%
	70,000 $+	1233	35.56%	393	37.43%	840	34.75%
Surgery	No	255	7.36%	94	8.95%	161	6.66%	0.048
	Yes	3193	92.10%	949	90.38%	2244	92.84%
	Unknown	19	0.55%	7	0.67%	12	0.50%
Radiotherapy	No/unknown	1711	49.35%	561	53.43%	1150	47.58%	0.002
	Yes	1756	50.65%	489	46.57%	1267	52.42%
Chemotherapy	No/unknown	916	26.42%	225	21.43%	691	28.59%	<0.001
	Yes	2551	73.58%	825	78.57%	1726	71.41%
Neoadjuvant therapy	Not given	2059	59.39%	544	51.81%	1515	62.68%	<0.001
	Yes	731	21.08%	278	26.48%	453	18.74%
	Unknown	677	19.53%	228	21.71%	449	18.58%

SEER: the Surveillance, Epidemiology, and End Results; sPR+: single progesterone receptor-positive.