Table 1.

Patient baseline demographics and disease characteristics

Characteristics	N = 266 N (%)
Age at metastatic breast cancer diagnosis (years)
Mean (SD)	57.0 (13.7)
Median	57.3
Min–max	22.2–92.1
Age category
<65 years old	188 (70.7)
≥65 years old	78 (29.3)
Geographic region
Northeast	11 (4.1)
Midwest	29 (10.9)
South	160 (60.2)
West	66 (24.8)
Payer type
Medicare	72 (27.1)
Medicaid	5 (1.9)
Private	168 (63.1)
Others	20 (7.5)
Unknown	1 (0.4)
Race
White/Caucasian	188 (70.7)
Black/African American	33 (12.4)
Asian	14 (5.3)
Native American	1 (0.4)
Hispanic	4 (1.5)
Other	2 (0.7)
No information	24 (9.0)
Metastatic breast cancer diagnosis
Recurrent mBC	135 (50.8)
de novo mBC	131 (49.2)
Disease-free interval (months)
N	135 (50.8)
Mean (SD)	51.4 (57.6)
Median	33.7
Min–max	3.8–471.8
Inflammatory breast cancer (IBC)
IBC disease	27 (10.2)
Non-IBC disease	239 (89.8)
Skin/chest wall involvement
Skin	39 (14.7)
Chest wall	5 (1.9)
Both	10 (3.8)
None	212 (79.6)
Tumor (histological) grade
G1	8 (3.0)
G2	63 (23.7)
G3	175 (65.8)
GX	14 (5.3)
No information	6 (2.2)
Primary tumor site
Left	129 (48.5)
Right	136 (51.1)
No information	1 (0.4)
Hormone receptor status
ER and PgR negative	111 (41.7)
ER and/or PgR positive	155 (58.3)
ECOG performance status (PS)
PS 0	64 (24.1)
PS 1	159 (59.8)
PS 2	30 (11.3)
PS 3	4 (1.5)
No information	9 (3.4)
Number of sites of metastases
1	62 (23.3)
2	76 (28.6)
3	52 (19.5)
4 and above	76 (28.6)
Charlson comorbidity index
0	208 (78.2)
1–2	52 (19.5)
3–4	6 (2.3)
≥5	0

SD standard deviation, DFI disease-free interval, IBC inflammatory breast cancer, ER estrogen receptor, PgR progesterone receptor, ECOG Eastern Cooperative Oncology Group, PS performance status