Table 3. Univariate analysis of PFS in EGFR exon 19 deletion-insertion for stage IV NSCLC patients receiving first-line therapy.

Characteristics	Median PFS in months (95% CI)	P value	HR (95% CI)	P value
Age at diagnosis, years
<65	15.497 (10.825–20.172)		1 (ref)
≥65	14.791 (9.187–20.395)	0.723	1.148 (0.525–2.510)	0.730
Gender
Female	13.376 (9.660–17.093)		1 (ref)
Male	16.794 (11.040–22.548)	0.418	1.377 (0.621–3.055)	0.432
Smoking status
No	14.299 (10.523–18.076)		1 (ref)
Yes	17.400 (9.504–25.296)	0.381	0.684 (0.285–1.644)	0.396
Exon 19 deletion-insertion subtypes
L747_P753delinsS	14.821 (9.917–19.726)		1 (ref)
L747_A750delinsP	23.500 (15.877–31.123)		0.306 (0.039–2.415)	0.261
L747_T751delinsP	26.667 (11.730–41.603)		0.266 (0.033–2.112)	0.210
Others	11.713 (7.786–15.639)	0.184	1.333 (0.587–3.029)	0.492
The first line of the therapy
First EGFR-TKI	16.653 (12.460–20.847)		1 (ref)
Second EGFR-TKI	13.600 (7.313–19.887)		1.136 (0.378–3.412)	0.820
Third EGFR-TKI	7.179 (3.969–10.388)	0.216	2.731 (0.833–8.953)	0.097
Best response
CR	19.000 (19.000–19.000)		1 (ref)
PR	15.855 (12.440–19.270)		1.222 (0.157–9.519)	0.848
SD	17.206 (9.555–24.858)	0.000	1.144 (0.135–9.688)	0.902

PFS, progression-free survival; EGFR, epidermal growth factor receptor; NSCLC, non-small cell lung cancer; HR, hazard ratio; CI, confidence interval; TKI, tyrosine kinase inhibitor; CR, complete response; PR, partial response; SD, stable disease.