Table 1. Association between patients’ demographics/clinical characteristics and baseline cfDNA levels.

Characteristics	N (%)	Baseline cfDNA, median (GE/mL)	P value
Age (years), median [range]; mean ± SD	67 [47–83]; 66.83±8.1
Below median	24 (52.17)	6,488.23	0.79
Above median	22 (47.82)	8,403.79
Gender
Male	39 (84.78)	6,130.59	0.61
Female	7 (15.22)	15,699.93
Stage
III	5 (10.87)	1,409.11	0.031
IV	41 (89.13)	7,658.99
ECOG PS
<2	31 (67.39)	4,652.13	0.025
≥2	15 (32.61)	22,459.61
Smoking
Smoker	26 (56.52)	6,488.23	0.94
Former smoker	20 (43.48)	6,155.56
Number of metastasis
≤2	22 (47.82)	4,563.83	0.05
>2	24 (52.17)	12,973.33
Liver metastases
No	23 (50.0)	3,355.91	0.0002
Yes	23 (50.0)	24,759.83
Bone metastases
No	18 (39.13)	3,265.055	0.17
Yes	28 (60.87)	3,355.91
Lymph node metastases
No	10 (21.74)	4,563.83	0.12
Yes	36 (78.26)	7,658.99
Treatment
Chemotherapy	33 (71.74)	6,130.59	0.36
Chemotherapy plus immunotherapy	13 (28.26)	10,676.99

cfDNA, cell-free DNA; GE, genomic equivalents; SD, standard deviation; ECOG PS, Eastern Cooperative Oncology Group Performance Status.