Table 4. Univariate and multivariate analyses of disease-free survival.

Factor	HR	95% CI	P value	HR	95% CI	P value
Male (vs. female)	1.120	0.470–2.671	0.798	–	–	–
Age ≥70 (vs. <70)	0.376	0.088–1.612	0.188	0.388	0.091–1.665	0.203
Smoking	0.987	0.426–2.285	0.976	–	–	–
p-N stage	3.797	1.646–8.758	0.002	3.824	1.658–8.821	0.002
SPC	0.044	0.000–38.082	0.365	–	–	–
Operative method
Lobectomy	1	–	–	1	–	–
Sublobar resection	0.000	0.000	0.982	0.000	0.000	0.983
Bilobectomy	3.220	1.048–9.896	0.041	2.694	0.868–8.365	0.086
Pneumonectomy	3.627	1.289–10.203	0.015	2.286	0.753–6.938	0.144
Histology
Adenocarcinoma	1	–	–	1	–	–
Squamous cell carcinoma	2.655	1.083–6.508	0.033	1.560	0.563–4.326	0.393
Mixed	6.497	0.812–51.962	0.078	4.382	0.523–36.706	0.173
Other	0.938	0.117–7.508	0.952	0.718	0.088–5.871	0.757
p-T stage
1	1	–	–	–	–	–
2	1.842	0.734–43624	0.193	–	–	–
3	1.386	0.287–6.699	0.684	–	–	–
4	0.000	0.000	0.984	–	–	–

HR, hazard ratio; CI, confidence interval; SPC, second primary cancer; p-, pathologic.