Table 2. Univariate and multivariate analysis of EGFR negative and positive patients.

Clinical factors	EGFR patients				Multivariate analysis
	− (N=750)	+ (N=251)	P value		OR (95% CI)	P value
Age, years, median [range]	67 [19–94]	66 [38–93]	0.230
Gender			<0.001			<0.001
Female	252 (33.6)	143 (57.0)			2.445 (1.811–3.301)
Male	498 (66.4)	108 (43.0)			1
Tumor stage			0.077			0.077
Stage III	267 (35.6)	74 (29.5)			1
Stage IV	483 (64.4)	177 (70.5)			0.796 (0.484–1.308)
Histology			0.001			0.029
Adenocarcinoma	635 (84.7)	233 (92.8)			1.825 (1.064–3.130)
Non-adenocarcinoma	115 (15.3)	18 (7.2)			1
Smoking history			<0.001			0.324
Never	387 (51.6)	170 (67.7)			1
Yes	363 (48.4)	81 (32.3)			0.887 (0.554–1.419)
Chemotherapy			0.006			0.016
Naive	572 (76.3)	212 (84.5)			1
After 1st line	178 (23.7)	133 (15.5)			0.615 (0.413–0.914)
Metastatic organs			0.001			<0.001
0	407 (54.3)	116 (46.2)			1
1	253 (33.7)	82 (32.7)			1.238 (0.885–1.730)	0.212
2–4	90 (12.0)	53 (21.1)			2.339 (1.546–3.539)	<0.001