Table 3. Cox regression analysis of the factors affecting the survival of 62 patients.

Characteristics	n	MST (month)	χ2	P
				Univariate	Multivariate
Age (years)			1.086	0.297
>60	30	19.5
≤60	32	21.9
PS (scores)			18.298	<0.001	0.015
>80	56	21.87
≤80	6	7.47
Gender			0.173	0.678
Male	49	19.5
Female	13	19.3
Smoking index			1.183	0.277
>400	38	17.0
≤400	24	21.9
Tumor size (cm)			1.478	0.224
>3	44	17.5
≤3	18	42.7
Lymph node metastasis			4.589	0.032	0.007
Yes	49	14.3
No	13	NR
Distant metastasis			7.781	0.005	0.007
Yes	26	42.7
No	36	10.1
Stage			10.980	0.001
I-II	10	NR
III-IV	52	17.0
No. of chemotherapy cycles			2.593	0.459
1-2 cycles	12	12.1
3-4 cycles	18	21.7
5-6 cycles	26	19.5
>6 cycles	6	NR
Chest radiotherapy			0.514	0.473
Yes	17	21.9
No	45
Prophylactic cranial irradiation			4.141	0.042	0.034
Yes	9	42.7
No	53	15.5
Surgical resection			6.889	0.009
Yes	15	NR
No	47	15.5
Second-line chemotherapy			5.477	0.242
No treatment	7	12.1
IP regimen	9	9.2
The original regimen	7	19.3
TP regimen	8	21.9
Local radiotherapy	4	12.5
Third-line chemotherapy			1.297	0.255
Yes	10	17.5
No	52	19.5

Smoking index, (number of cigarettes smoked per day) × years; NR, not reached; KPS: Karnofsky Performance Status; IP regimen, irinotecan plus platinum; TP regimen, paclitaxel plus platinum; MST, median survival time.