Author of

• 14490

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  P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)

  • Event: WCLC 2015
  • Type: Poster
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)

  • 14573

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    P2.04-083 - Influence of Surgery on EGFR Mutation Abundance among Patients with Early-Stage Non–Small-Cell Lung Cancer (ID 1142)

    09:30 - 09:30  |  Author(s): C. Yang
    • Abstract
    • Slides

    Background:
    Detecting circulating plasma cell-free DNA (cfDNA) in patients with early-stage cancer has the potential to change how oncologists recommend systemic therapies for solid tumors after surgery. However, it remains unclear whether surgery affects epidermal growth factor receptor (EGFR) mutation abundance in early-stage non–small-cell lung cancer (NSCLC). We investigated the influence of surgery on EGFR mutations in plasma and tumor tissues from patients with early-stage NSCLC.
    
    Methods:
    In this prospective study, primary lung tumors and matched pre- and postsurgery blood samples were collected from patients with early-stage NSCLC (n=96). We detected EGFR mutations (exon19 deletions, T790M and L858R) in 96 early-stage lung cancer samples using droplet digital PCR (ddPCR) and amplification refractory mutation system (ARMS). EGFR mutation abundance was determined and analyzed to reveal potential impact of surgery.
    
    Results:
    Presurgery plasma samples (n=96) matched tumor tissue samples (n=96) were analyzed for EGFR mutations using ddPCR and ARMS respectively. Of the 56 EGFR mutations detected in tumor tissues by ARMS, 48 of the corresponding mutations were detected in presurgical cfDNA, whereas no mutations were found in plasma from patients with EGFR wild-type tumors (sensitivity 85.71%, specificity 100%). Forty patients with mutation-positive cfDNA presurgery had ddPCR analysis of postsurgery plasma, with twenty-four patients having detectable cfDNA postsurgery. The decrease in EGFR mutation abundance was statistically significant (0.22 vs 0.04, P <0.05).
    
    Conclusion:
    This study demonstrates accurate mutation detection in plasma using ddPCR, and that cfDNA can be detected in blood before and after surgery in patients with early-stage lung cancer. Our results suggest that surgery may reduce EGFR mutation abundance in early-stage NSCLC patients with mutation-positive cfDNA presurgery. Future studies can now address whether monitoring the change of EGFR mutation abundance after surgery identifies patients at risk forrecurrence, which could guide therapy decisions for individual NSCLC patients.
    
    

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