In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 35, No. 15_suppl ( 2017-05-20), p. e20625-e20625
Abstract:
e20625 Background: T790M mutation is the most common mechanism of acquired EGFR TKI resistance. The use of T790M-targeted EGFR TKIs needs re-biopsy to confirm the existence of sensitive mutation. People wonder whether blood can replace tissue to diagnose acquired T790M mutation. Methods: We performed a prospective study in our institution (West China Hospital, Chengdu, China) between 2014 and 2016. Patients were eligible if they have advanced EGFR-mutant NSCLC, clinical resistance to EGFR TKIs, and were undergoing a re-biopsy for EGFR genotyping as part of their routine clinical care. We used ARMS to sequence EGFR of tissue and blood sample. Blood collection was performed within 2 weeks of the repeat biopsy. Measurement of diagnostic concordance among two different methods was done using cohen’s kappa, and the McNemar test used to judge significance. All statistical analysis was performed with the use of SPSS 20.0. Results: Forty-five patients were enrolled in this study. Thirty-eight patients received tissue test, thirty-one patients received plasma ctDNA test, and twenty-four patients received both tissue and plasma ctDNA tests. 26/38 (38.4%) reported positive T790M mutation by tissue test, and 13/31 (41.9%) by plasma ctDNA test. In 24 patients received both tissue and plasma ctDNA tests, 10/24 (41.7%) were concordant for T790M mutation status (κ = 0.006, p = 0.013). The positive rate of T790M mutation is 70.8% by tissue test, and 37.5% by plasma ctDNA test. In 17 patients reported positive T790M mutation by tissue test, 7/17 (41.2%) also reported positive T790M mutation by plasma ctDNA test, and 3 of the 7 positive ctDNA tests (42.9%) reported weakly positive T790M mutation. In the other 7 patients reported negative T790M mutation by tissue test, 2/7 (28.6%) reported positive T790M mutation by plasma ctDNA test. Conclusions: The positive rate of ARMS in our study is high than that of some reported new technologies. The level of plasma ctDNA was reported to relate to prognosis. Hence, plasma ctDNA cannot fully replace tissue to diagnose acquired T790M mutation after disease progression. It is important and significant to develop new technology to improve the safety of tissue biopsy.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2017.35.15_suppl.e20625
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2017
detail.hit.zdb_id:
2005181-5
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