Correlation between epidermal growth factor receptor tyrosine kinase inhibitor efficacy and circulating tumor cell levels in patients with advanced non-small cell lung cancer

Figures & data

Table 1 Correlation between CTC count and clinical factors in patients with advanced NSCLC

Clinical factors	n	CTC ($\overline{x}\pm s$)	t	P-value
Gender			2.573	0.11
Male	40	133.9±249.6
Female	26	19.3±21.5
Age (years)			1.523	0.13
≥60	26	101.6±253.3
<60	40	80.4±163.1
Histologic type			0.838	0.39
Squamous cell carcinoma	8	92.8±168.8
Adenocarcinoma	58	116.6±208.6
Clinical stage			0.795	0.43
IIIB	4	21.5±5.5
IV	62	93.1±207.6
PS score			1.351	0.18
0–1	44	93.5±217.3
≥2	22	79.2±171

Abbreviations: CTC, circulating tumor cell; NSCLC, non-small cell lung cancer; PS, performance status; s, standard deviation.

Table 2 Correlation between CTC count and efficacy of EGFR-TKI

Group	n	CTC count ($\overline{x}\pm s$)	CR	PR	SD	PD	RR (%)	X^2	P-value	DCR	X^2	P-value
Low count group	30	21.5±8.3	2	14	8	6	53.3	11.47	0.007	80	8.665	0.003
High count group	36	118.3±168	0	10	6	20	27.8			44.4

Abbreviations: CR, complete response; CTC, circulating tumor cell; DCR, disease control rate; EGFR, epidermal growth factor receptor; PD, progressive disease; PR, partial response; RR, response rate; SD, stable disease; TKI, tyrosine kinase inhibitor; s, standard deviation.

Table 3 Changes in CTC count before and after EGFR-TKI treatment

Group	n	Before treatment	After treatment	t	P-value
Effective	40	19.4±20.1	14.8±12.3	2.46	0.009
Noneffective	26	195.4±292.9	107.6±227	1.55	0.078

Abbreviations: CTC, circulating tumor cell; EGFR, epidermal growth factor receptor; TKI, tyrosine kinase inhibitor.

Figure 1 Correlation between CTC count and survival in patients with advanced NSCLC.

Abbreviations: CTC, circulating tumor cell; EGFR, epidermal growth factor receptor; NSCLC, non-small cell lung cancer; OS, overall survival; TKI, tyrosine kinase inhibitor.

Figure 2 Correlation between CTC count and PFS in patients with advanced NSCLC.

Abbreviations: CTC, circulating tumor cell; EGFR, epidermal growth factor receptor; NSCLC, non-small cell lung cancer; PFS, progression-free survival; TKI, tyrosine kinase inhibitor.

Table 4 Different mutation state of EGFR showing the different curative effect of EGFR-TKI

Group	n	CTC count ($\overline{x}\pm s$)	CR	PR	SD	PD	RR (%)	X^2	P-value	DCR	X^2	P-value
EGFR 19 exons	35	98.5±121.1	2	13	6	14	42.9	4.38	0.21	60	2.17	0.54
EGFR L858R exons	31	108.2±141.3	0	11	8	12	35.5			61.3

Abbreviations: CR, complete response; CTC, circulating tumor cell; DCR, disease control rate; EGFR, epidermal growth factor receptor; PD, progressive disease; PR, partial response; RR, response rate; SD, stable disease; TKI, tyrosine kinase inhibitor; s, standard deviation.