Genetic diagnostic features after failure of initial treatment with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors among non-small-cell lung cancer patients harboring EGFR mutations

Table 5 Background characteristics on patients harboring the T790M substitution upon rebiopsy (n = 89)

Variable	T790M mutation
Variable	Positive (n = 35)	Negative (n = 54)	Total
Original mutation
Absent	3	40	43
Present	32	14	46
Type of Biopsy;
Liquid	11	47	58
Tissue	24	7	31
Detection of New tumor lesion;
< 4	11	39	50
4 ≤	24	15	39
Number of Tissue biopsy
Median (Range)	1 (0–4)	0 (0–3)	0 (0–4)
Detection of New metastatic organ, n = 88
0	12	39	51
1	12	10	22
2	4	4	8
3	3	1	4
4	3	0	3
Number of tumor lesion
< 6	6	29	35
6 ≤	29	25	54
Brain metastases, n = 88
Absent	16	43	59
Present	18	11	29
Bone metastases, n = 88
Absent	26	42	68
Present	8	12	20
Number of Liquid biopsy
Median (Range)	0 (0–8)	2 (0–9)	1 (0–9)
Enlargement of Tumor size
< 12 mm	15	39	54
12 mm ≤	20	15	35
New brain metastases, n = 88
Absent	25	50	75
Present	9	4	13
Mutation site at initial diagnosis
Exon19 Deletion	24	47	71
L858R	11	7	18
Minor site metastases, n = 88
Absent	27	51	78
Present	7	3	10
New hepatic metastases, n = 88
Absent	28	51	79
Present	6	3	9
New minor site metastases, n = 88
Absent	29	52	81
Present	5	2	7
Hepatic metastases, n = 88
Absent	27	49	76
Present	7	5	12

Abbreviations: n; number, minor site metastases; metastases of skin, kidney, ascites, lymphangiosis carcinomatosa, adrenal organ or others,

ISSN: 1471-2407