Table 1.

Baseline characteristics of patients with bone metastatic breast cancer (BMBC) included from SEER data cohort.

Characteristic		Cases	%
Age at diagnosis	< 40	1,113	7.36
	40–49	1,962	12.97
	50–59	3,674	24.28
	60–69	3,985	26.34
	70–79	2,643	17.47
	80+	1,752	11.58
	0 month	5,609	37.07
Months from diagnosis to therapy	≥1 month	7,271	48.06
	unknown	2,249	14.87
	HR+/HER2–	8,652	57.19
	HR+/HER2+	2,151	14.22
Subtype	HR–/HER2+	915	6.05
	HR–/HER2–	1,189	7.86
	Unknown	2,222	14.69
Race	White	11,604	76.70
	Black	2,042	13.50
	Other	1,483	9.80
Histological type	IDC	9,634	63.68
	ILC	1,710	11.30
	Mixed	840	5.55
	Other	2,945	19.47
	Married	6,421	42.44
Marriage status	Singled	3,550	23.46
	Widow/divorced/other	5,158	34.09
T Stage	T1	1,782	11.78
	T2	4,345	28.72
	T3	2,259	14.93
	T4	4,461	29.49
	Unknown	2,282	15.08
N Stage	N0	3,197	21.13
	N1	6,619	43.75
	N2	1,471	9.72
	N3	3,065	20.26
	Unknown	777	5.14
Grade	I; well differentiated	1,014	6.70
	II; moderate differentiated	5,115	33.81
	III/IV; poorly differentiated	4,687	30.98
	Unknown	4,313	28.51
Median household income (inflation adjusted)	< 50,000$	1,881	12.43
	50,000–59,999$	2,416	15.97
	60,000–69,999$	5,030	33.25
	70,000$	5,802	38.35
Neoadjuvant chemotherapy	No/unknown	14,097	93.18
	Yes	1,032	6.82
Chemotherapy	No/unknown	7,102	46.94
	Yes	8,027	53.06
Radiotherapy	No/unknown	9,962	65.85
	Yes	5,167	34.15
Surgery	No/unknown	12,047	79.63
	Yes	3,082	20.37
Liver metastases	No/unknown	11,439	75.61
	Yes	3,690	24.39
Lung metastases	No/unknown	11,082	73.25
	Yes	4,047	26.75
Brain metastases	No/unknown	14,023	92.69
	Yes	1,106	7.31
Distant lymph nodes metastases	No/unknown	13,642	90.17
	Yes	1,487	9.83
Distant other metastases	No/unknown	14,151	93.54
	Yes	978	6.46