Table 2. Univariate analysis of the factors associated with overall survival.

Univariate analysis	CEA-positive					CYFRA 21-1-positive
	n	Median OS (months)	95% CI (months)	P value		n	Median OS (months)	95% CI (months)	P value
Age, years				0.150					0.298
<70	52	14.8	11.3–19.2			35	13.4	7.8–15.5
≥70	44	20.4	12.4–29.2			20	14.6	8.9–39.6
Sex				0.505					0.394
Male	68	14.8	10.6–20.4			44	11.3	8.9–15.5
Female	28	18.4	13.0–27.2			11	18.5	7.5–33.2
History of smoking				0.059					0.135
None	24	27.2	13.0–32.9			10	20.2	4.3–NA
Current + former	72	13.7	10.6–19.2			45	11.3	8.9–15.4
ECOG PS				0.315					0.023
0, 1	81	16.4	13.0–20.6			53	14.8	10.0–16.3
2	15	12.6	6.4–26.7			2	7	6.7–NA
Stage				0.398					0.207
IIIB	11	13	6.8–23.4			10	15.1	6.2–NA
IV + postoperative recurrence	85	16.9	13.0–20.6			45	11.3	9.3–15.6
Histology				0.426					0.275
Adenocarcinoma	78	16.9	13.0–20.6			31	12.9	9.3–16.3
Non-adenocarcinoma	18	13	7.8–31.9			24	15.1	7.8–31.9
EGFR mutation status				0.022					0.185
Positive	35	22.1	16.9–29.2			8	18.5	4.3–NA
Negative	61	12.9	10.0–16.3			47	11.3	8.9–15.5
Tumor marker levels at baseline				0.200					0.385
High¶	47	13.4	10.4–19.6			27	13.4	6.7–15.6
Low	49	18.4	13.0–27.2			28	13.2	9.3–30.9
Imaging-based response				0.008					0.018
PR, SD	61	18.4	13.0–26.7			26	15.1	10.0–31.9
PD	25	12.9	6.4–19.2			24	7.5	6.2–13.4
Tumor marker response at 1 month				0.684					0.016
Decreasing	74	16.9	12.9–20.6			47	15.1	10.3–16.4
Non-decreasing	21	13.4	8.3–33.2			8	7.2	5.0–12.9
Tumor marker response at 4 months				0.025					<0.001
Decreasing	79	16.9	13.0–22.1			39	15.5	11.3–21.5
Non-decreasing	17	10.3	6.3–19.2			16	7.2	6.1–9.4

^¶, high tumor marker levels at baseline were defined as >30 mg/dL for CEA and >10 mg/dL for CYFRA. CEA, carcinoembryonic antigen; CI, confidence interval; CYFRA 21-1, cytokeratin 19 fragment; ECOG PS, Eastern Cooperative Oncology Group performance status; EGFR, epidermal growth factor receptor; PR, partial response.