Author of

• 18975

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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)

  • 23900

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    P3.01-041 - The Robustness of Allele-Specific qPCR Assays for Detection of EGFR Mutations in Plasma Cell-Free DNA from NSCLC Patients (ID 9409)

    09:30 - 09:30  |  Author(s): P. Wojcik
    • Abstract

    Background:
    The analysis of EGFR mutations in plasma cell-free DNA (cfDNA) may become an auxiliary tool in the molecular diagnosis of advanced NSCLC patients from whom sufficient tumor tissue/cells specimens cannot be obtained. We evaluated the diagnostic performance of the two most common real-time PCR-based platforms for detection of EGFR mutations in plasma cfDNA that we use in our routine laboratory practice.
    
    Method:
    EGFR mutations were analyzed in plasma cfDNA collected from 107 NSCLC patients (non-SQC type, stages I-IV) before treatment (n=80) or at the time of progression on EGFR-TKIs (n=27) using two IVD-marked assays: ‘Cobas EGFR Mutation Test v2’ (Roche) and ‘Therascreen EGFR Plasma RGQ PCR Kit’ (Qiagen).
    
    Result:
    The overall concordance between EGFR mutation status in plasma cfDNA and paired tumor tissue samples was 62% (46% for Cobas and 32% for Therascreen test) for all patients regardless the NSCLC stage. The concordance increased to 88% (83% for Cobas and to 56% for Therascreen) when only samples from advanced NSCLC patients were evaluated. Accordingly, the Cobas test showed higher positive percent agreement between cfDNA and tissue results (PPA=83%) than did the Therascreen test (PPA=56%). Both test showed 100% negative percent agreement. The T790M mutation was detected in 26% cfDNA samples from patients upon progression on EGFR-TKIs. In 12 (44%) cases with progressive disease, the plasma cfDNA was the only specimen available for EGFR mutation analysis.
    
    Conclusion:
    In our laboratory setting, Cobas test demonstrated superior diagnostic performance over Therascreen assay in detection of EGFR mutations in plasma cell-free DNA from advanced NSCLC patients. Since analysis of mutated EGFR cfDNA in plasma is troublesome laboratory procedure, we recommend to validate the true diagnostic performance of each commercial assay in a specific laboratory conditions despite its IVD certification. The study is on-going.