Table 3.

Factors related to detection of ^†EGFR mutation by liquid biopsy

	EGFR mutation positive (n = 19)	EGFR mutation negative (n = 11)	P value
Age, median (range), years	68.0 (54–82)	69.0 (55–81)	0.5315
histology, n (%) (adenocarcinoma/ adenosquamous)	19 (89.4%) (17/2)	11 (100%) (11/0)	0.5195
N2 or higher, n (%)	13 (68.4%)	5 (45.4%)	0.2663
M factor, n (%)	18 (89.4%)	9 (81.8%)	0.5367
LDH, median, U/L	217	189	0.0776
ALP, median, U/L	304	225	0.0048
CRP, median, mg/dl	0.53	0.12	0.0501
CEA, median, ng/mL	39.1	10.6	0.2307
extrathoracic metastasis, n (%)	17 (89.4%)	3 (27.2%)	0.0010
brain metastasis, n (%)	7 (36.8%)	0	0.0292
liver metastasis, n (%)	5 (26.3%)	0	0.0527
adrenal metastasis, n (%)	7 (36.8%)	0	0.0292
bone metastasis, n (%)	12 (63.1%)	3 (27.2%)	0.1281

^†EGFR Epidermal growth factor receptor, LDH Lactate dehydrogenase, ALP Alkaline phosphatase, CRP C-reactive protein, CEA carcinoembryonic antigen