Table 3.

Multivariate cox regression analysis of OS.

Characteristic	P-value	HR (95%CI)
Gender	0.328	0.732 (0.392–1.367)
Age (years)	0.545	0.891 (0.614–1.294)
Smoking index	0.558	0.856 (0.510–1.439)
Pathologic T1	0.000
T2	0.004	2.024 (1.260–3.251)
T3	0.023	1.986 (1.101–3.585)
T4	0.000	4.050 (2.071–7.920)
No. of metastatic N2 lymph nodes	0.000	2.664 (1.750–4.053)
Postoperative adjuvant chemotherapy	0.032	1.718 (1.048–2.818)
Thoracic radiation therapy (TRT)	0.008	1.921 (1.185–3.114)
Prophylactic cranial irradiation (PCI)	0.047	1.549 (1.005–2.388)