Table 3. Univariate analysis of the correlation between clinicopathological variables and disease-free survival of NSCLC patients.

Clinicopathological variables	Median DFS (months)	Univariate analysis				Multivariate analysis
		HR	95% CI	P value		HR	95% CI	P value
Age (years)		1.390	0.820–2.357	0.221		–	–	–
≥60	NA
<60	NA
Sex		0.931	0.556–1.561	0.787		–	–	–
Female	NA
Male	NA
Smoking history		0.783	0.415–1.476	0.449		–	–	–
Never	NA
ever	NA
Tumor invasion		1.100	0.440–2.753	0.838		–	–	–
T1–T2	NA
T3–T4	NA
N stages		5.706	3.229–10.083	0.000		–	–	–
N0	NA
N1–N3	39.00±5.38
TNM stages		7.038	4.092–12.105	0.000		4.803	2.692–8.567	0.000
I–II	NA
III	30.00±6.99
ctDNA EGFR mutation		9.494	5.401–16.687	0.000		4.860	2.660–8.880	0.000
Positive	19.00±2.50
Negative	NA
Tumor differentiation		2.428	1.364–4.321	0.003		1.438	0.792–2.612	0.233
High and moderate	NA
Poor	41.00±14.12
Pathological subtype		1.243	0.450–3.432	0.675		–	–	–
Adenocarcinoma	NA
Others	NA

NSCLC, non-small cell lung cancer; DFS, disease-free survival; HR, hazard ratio; CI, confidence interval; TNM, tumor-node-metastasis; ctDNA, circulating tumor DNA; EGFR, epidermal growth factor receptor.