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NamEun Kim
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EP1.01 - Advanced NSCLC (ID 150)
- Event: WCLC 2019
- Type: E-Poster Viewing in the Exhibit Hall
- Track: Advanced NSCLC
- Presentations: 1
- Now Available
- Moderators:
- Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
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EP1.01-09 - Clinical Efficacy of Circulating Tumor DNA Test in Advanced Non-Small-Cell Lung Cancer Patients Who Might Have T790M Mutation (Now Available) (ID 1673)
08:00 - 18:00 | Presenting Author(s): NamEun Kim
- Abstract
Background
Using EGFR-tyrosine kinase inhibitors (TKIs) in patients with advanced lung cancer led to a significant improvement in survival. However, patients with these TKIs are ultimately resistant to disease, and about 50-60% patients showed EGFR T790M mutation. The purpose of this study was to evaluate the efficacy of tissue biopsy and liquid biopsy in patients undergoing re-biopsy after TKI use.
Method
We reviewed medical records of 85 NSCLC patients who had done both tissue rebiopsy and liquid sampling from december 2017 to december 2018, at Severance University Hospital, Seoul, Korea. In this patients, the degree of coincidence and an expression level of T790M were examined with rebiopsy tissue for EGFR and circulating tumor DNA (ct DNA). CtDNA in plasma requires 100 copies of EGFRT790M per milliliter of plasma, so allele-specific PCR and digital PCR method were used to increase sensitivity for detection..
Result
The mean age of the 85 patients was 62.9 ± 11.1 years, and 50 (58.8%) were female. The expression of T790M on rebiopsy was 17.6% (15/85) in ct DNA, and 23.5% (20/85) in tissue. The percentage of T790M from either liquid biopsy or tissue biopsy was 31.4% (27/85). The concordance between liquid biopsy and tissue biopsy was 72.9%. The sensitivity of liquid biopsy was 27%, specificity 72%, positive predictive value 22% and negative predictive value 77%.
Conclusion
Testing Circulating tumor DNA in patients with NSCLC after TKI use can help to find T790M mutation in addition to rebiopsy of tissue. Combination of liquid biopsy and tissue biopsy is complementary to find the subject of the third-generation TKI, osimertinib. Also, liquid biopsy is less invasive and repeatable than tissue biopsy, it is useful for group of negative finding at tissue biopsy initial