Table 1.

Detailed patient characteristics (n = 47).

Age
Mean/IQR (years)	57.1 ± 13.4
ECOG PS
0	23	49%
1	23	49%
2	1	2%
Histology
Invasive ductal	38	83%
Invasive lobular	8	17%
Unknown	1
Grade
G1	8	22%
G2	17	47%
G3	11	31%
Unknown	11
Current disease status
Metastatic	45	96%
Lung or liver	35	74%
Bone only	6	13%
Other	4	9%
Locally advanced	2	4%
N Metastatic sites
0	2	4%
1–2	24	51%
≥3	21	45%
KI-67 (primary)
<10%	5	14%
10–15%	9	24%
16–25%	6	16%
>25%	17	46%
Unknown	10
Prior CDK 4/6
No	35	74%
Yes	12	26%
Number of lines CT in advanced setting
0	20	43%
1	14	30%
≥2	13	28%
Number of lines ET in advanced setting
0	2	4%
1	13	28%
≥2	32	68%
NSAI sensitive
No	13	30%
Yes	34	70%

Baseline patient demographics (n = 47).

Represents baseline characteristics of the 47 patients considered to be eligible according to the 18F-FDG-PET/CT eligibility criteria (details in Method section).

IOR = interquartile range; ECOG PS = Eastern Cooperative Oncology Group performance status, ranging from 0 to 5, 0 indicating that the patient is fully active and able to carry on all pre-disease performance without restriction; at 1, restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature; at 2, ambulatory and capable of all self-care but unable to carry out any work activities; up to about more than 50% of waking hours; N Metastatic sites = number of metastatic sites; Ki-67 = cell proliferation marker (immunohistochemistry); CDK 4/6 = cyclin-dependent kinase 4/6 inhibitor; CT = chemotherapy; ET = endocrine therapy; NSAI = non-steroidal aromatase inhibitor; sensitive is defined as relapse ≥2 years after the end of an NSAI in the adjuvant setting, or ≥6 months of treatment in the metastatic setting.