Table 4. Univariate and multivariate analyses of DFS and OS in patients with primary lung adenocarcinoma.

Factors		DFS				OS
		Univariate analysis		Multivariate analysis		Univariate analysis		Multivariate analysis
		HR (95%CI)	P value	HR (95%CI)	P value	HR (95%CI)	P value	HR (95%CI)	P value
Age (years)	≥70/<70	1.46 (1.04–2.05)	0.0288	1.67 (1.19–2.36)	0.0030	2.71 (1.72–4.37)	< 0.0001	3.67 (2.30–6.00)	< 0.0001
Sex	Male/female	1.91 (1.36–2.72)	0.0002			2.42 (1.54–3.90)	0.0001	2.33 (1.47–3.78)	0.0003
Smoking status	Smoker/never smoked	1.52 (1.08–2.15)	0.0159			1.78 (1.15–2.80)	0.0097
Grade	≥G2/G1	4.03 (2.73–6.13)	< 0.0001	2.31 (1.51–3.63)	< 0.0001	3.80 (2.30–6.60)	< 0.0001
Stage	≥II/I	5.28 (3.75–7.47)	< 0.0001	3.30 (2.27–4.81)	< 0.0001	4.23 (2.73–6.59)	< 0.0001	2.78 (1.69–4.61)	< 0.0001
pl	Yes/no	3.47 (2.44–4.90)	< 0.0001			3.65 (2.34–5.65)	< 0.0001
ly	Yes/no	4.95 (3.42–7.06)	< 0.0001	2.60 (1.75–3.82)	< 0.0001	4.28 (2.68–6.70)	< 0.0001	2.76 (1.65–4.53)	0.0001
v	Yes/no	3.08 (2.19–4.33)	< 0.0001			3.58 (2.31–5.56)	< 0.0001	1.83 (1.11–3.03)	0.0183
Histological subtype	Micropapillary or solid/others	2.06 (1.15–3.40)	0.0166			1.14 (0.44–2.42)	0.7572
Surgical procedure	≥Lobectomy/sublobar resection	1.60 (1.04–2.56)	0.0322			1.66 (0.95–3.14)	0.0787
EGFR*	Wild-type/mutant	1.76 (1.10–2.89)	0.0185			2.21 (1.18–4.40)	0.0128
IL-38	High/low	1.75 (1.23–2.52)	0.0018			2.00 (1.26–3.26)	0.0030

*cases for which data were available.

P-values for Cox proportional hazards regression analysis.

DFS: disease-free survival, OS: overall survival, pl: pleural invasion, ly: lymphatic invasion, v: vascular invasion, EGFR: epidermal growth factor receptor gene, IL-38: interleukin-38, HR: hazard ratio, CI: confidence interval.