Author of

• 30601

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  P2.01 - Advanced NSCLC (ID 159)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 30637

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    P2.01-36 - A Pilot Study on Cerebrospinal Fluid Cell-free DNA Sequencing in Leptomeningeal Metastasis from Non-Small Cell Lung Cancer (ID 1782)

    10:15 - 18:15  |  Presenting Author(s): Xi Wu
    • Abstract

    Background
    

    Leptomeningeal metastasis (LM) is a devastating complication of non-small cell lung cancer (NSCLC) with poor prognosis. It is difficult to determine the genomics alternations and assess the therapeutic responses. The purpose of this study was to detect the cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) from NSCLC patients with LM, and to explore the whole genome and chromosomal alterations information of tumors.

    Method
    

    From 2016 October to 2019 February, a total of 40 lung adenocarcinoma patients with LM were enrolled. Paired 10 ml CSF and 10 ml blood samples were collected before intrathecal chemotherapy. Gene mutations of cfDNA in plasma and CSF were detected by second-generation sequencing (NGS). Three cases of NSCLC-LM CSF cfDNA were sequenced by whole genome sequencing (WGS) to screen chromosome instability (CIN).

    Result
    

    Among 40 patients with LM from NSCLC, median age was 56 (range, 39-77), 47.8% were female, 85.0% had EGFR mutation, 7.5% ALK rearrangement and 7.5% other activating mutations. Driver genes were detected much higher in CSF cfDNA than plasma cfDNA (100% vs 57.5%). 237 specific genetic mutations were captured in CSF cfDNA, while only 48 specific mutations were detected in plasma. Copy number variations（CNV）were totally identified in CSF cfDNA, however, no CNV was detected in plasma. The three NSCLC-LM CSF cfDNA samples had either short arm deletion on chromosome 8 or short arm amplification on chromosome 5.

    Conclusion
    

    Compared with plasma cfDNA, CSF cfDNA was more sensitive to the detection of LM genomic alterations. We suggest that CSF cfDNA would representative to the LM lesions, it could dynamically monitor the disease progression and guide precision therapies. Whether genome wide doubling (WGD) and CIN can predict overall survival or recurrence risk needs further exploration.