Table 2. Univariate and multivariate Cox regression model for PFS and OS based on the cfDNA concentration in patients with NSCLC.

Variables		Univariate analysis				Multivariate analysis
		PFS		OS		PFS		OS
	n/N (%)	HR (95% CI)	p value	HR (95% CI)	p value	HR (95% CI)	p value	HR (95% CI)	p value
All patients with NSCLC
cfDNA (>70 ng/mL)	75/177 (42)	2.17 (1.47–3.20)	< 0.001	2.60 (1.65–4.10)	< 0.001	2.60 (1.65–4.10)	< 0.001	2.63 (1.66–4.17)	< 0.001
Age (> median)	95/177 (54)	1.03 (0.70–1.52)	0.856	1.42 (0.90–2.23)	0.126	0.95 (0.62–1.44)	0.808	1.05 (0.64–1.71)	0.836
Sex (male)	115/177 (65)	1.00 (0.67–1.50)	0.979	1.47 (0.90–2.39)	0.117	1.07 (0.71–1.63)	0.727	1.48 (0.90–2.46)	0.120
ECOG status (>1)	28/177 (16)	2.10 (1.25–3.52)	0.005	2.71 (1.59–4.63)	< 0.001	1.89 (1.09–3.28)	0.023	2.64 (1.48–4.69)	0.001
Charlson Comorbidity Index (>7)	127/177 (72)	1.97 (1.22–3.19)	0.006	2.23 (1.19–3.70)	0.010	0.99 (0.51–1.91)	0.989	1.21 (0.58–2.52)	0.601
Stage IV	137/177 (77)	2.68 (1.54–4.66)	< 0.001	2.33 (1.25–4.35)	0.007	2.29 (1.09–4.77)	0.027	1.88 (0.86–4.14)	0.113
Stage IV chemo-naive ADC only
cfDNA (>70 ng/mL)	50/112 (45)	2.11 (1.32–3.37)	0.008	3.08 (1.71–5.57)	< 0.001	2.21 (1.37–3.55)	0.001	3.50 (1.90–6.45)	< 0.001
Age (> median)	57/112 (51)	1.07 (0.67–1.70)	0.774	1.51 (0.85–2.68)	0.154	1.10 (0.64–1.89)	0.722	1.30 (0.68–2.48)	0.427
Sex (male)	67/112 (60)	0.96 (0.60–1.55)	0.888	1.49 (0.82–2.71)	0.187	1.12 (0.66–1.90)	0.653	1.76 (0.89–3.45)	0.101
ECOG status (>1)	22/112 (20)	1.69 (0.95–3.00)	0.073	2.53 (1.35–4.73)	0.004	1.92 (1.03–3.59)	0.040	3.02 (1.49–6.13)	0.002
Charlson Comorbidity Index (>7)	98/112 (88)	0.70 (0.37–1.35)	0.295	1.09 (0.49–2.46)	0.820	0.56 (0.26–1.23)	0.152	0.72 (0.27–1.96)	0.534

PFS, progression-free survival; OS, overall survival; NSCLC, non-small-cell lung cancer; HR, hazard ratio; CI, confidence interval; cfDNA, cell-free DNA; ECOG, Eastern Cooperative Oncology Group; ADC, adenocarcinoma