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Y. Ito
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-064 - Detection of EGFR Mutations in Circulating Tumor DNA Using Plasma Samples: Clinical Validation of Cobas EGFR Mutation Test V2 (ID 10095)
09:30 - 09:30 | Author(s): Y. Ito
- Abstract
Background:
Detection of EGFR mutations in circulating tumor DNA using plasma samples is non-invasive and safety method. Cobas EGFR mutation test v2 with tumor tissue has been approved for detection of EGFR mutations to offer EGFR-TKI therapy in Japan. Recently, cobas test v2 using plasma samples at disease progression after prior EGFR-TKI therapy was approved for detection of T790M mutation. However, diagnostic accuracy of this test using plasma samples has not yet known in clinical practice.
Method:
This study is a single-center retrospective study. Between May 2016 and June 2017, we obtained 70 plasma samples from 53 advanced NSCLC patients harboring EGFR mutation in our hospital, and evaluated concordance rate of tissue and plasma EGFR mutation status using sensitivity and specificity. All plasma samples were tested using cobas EGFR mutation test v2.
Result:
70 samples were classified into three cohorts, diagnostic cohort(n=22), continuing response cohort(n=10), and acquired resistance cohort(n=38) by clinical setting. In diagnostic cohort, sensitivity for major mutations was 89%(ex19=100%, L858R=83%, respectively). In all cohorts, sensitivity for major mutations was 70%(ex19=80%, L858R=65%, respectively). T790M detection was evaluated in acquired resistance cohort, sensitivity was 67%, and specificity was 74%, respectively.
Conclusion:
The cobas EGFR mutation test v2 using plasma samples had good accuracy for detection of EGFR mutation in diagnostic setting. On the other hand, there was moderate accuracy for T790M detection in acquired resistance setting.