Table 4 Association between cfDNA levels and clinicopathological characteristics and survial

Gender (Female)

0.61

(0.19–1.64)

0.356

Age (≥ 65)

1.23

(0.51–2.96)

0.641

Smoking history (Yes)

2.03

(0.79–5.03)

0.130

ECOG PS (1–2)

0.68

(0.19–3.15)

0.571

Primary site (Right)

0.84

(0.35–2.01)

0.690

Histology (Squamous cell carcinoma and others)

0.93

(0.29–2.54)

0.894

Degree of differentiation (High)

0.74

(0.20–2.14)

0.602

Stage (IV)

0.71

(0.23–2.67)

0.579

Extrapulmonary metastasis (Yes)

0.71

(0.29–1.71)

0.453

Tumor size (≥ 5(cm))

1.84

(0.72–4.57)

0.191

BT3 cfDNA (≥ 41.46(ng/mL))

3.06

(2.61–21.71)

< 0.0001

6.08

(1.94–19.57)

0.002

BT3-BT1 cfDNA

(≥ 2.36(ng/mL))

2.62

(1.09–6.52)

0.032

1.54

(0.55–4.21)

0.398