Author of

• 34780

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  P37 - Pathology - Biomarker Testing (ID 107)

  • Event: WCLC 2020
  • Type: Posters
  • Track: Pathology, Molecular Pathology and Diagnostic Biomarkers
  • Presentations: 1
  • Moderators:
  • Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall

  • 34799

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    P37.15 - Prevalence of Targetable Mutations using a RT-qPCR Multiplex Assay in Asian NSCLC Patients: A Single Laboratory Experience (ID 3296)

    00:00 - 00:00  |  Presenting Author(s): Shi Feng Nyaw
    • Abstract
    • Slides

    Introduction
    

    Genotyping is the cornerstone of NSCLC management. > 50% of Asian oncologists preferred multiplex testing for genotyping NSCLC in a global survey, but reports on the performance of these platforms in this region are limited (Smeltzer et al, 2020). In Hong Kong and Thailand, reflexive testing of EGFR status using real-time PCR, and ALK status using immunohistochemistry and fluorescent in-situ hybridisation is widely practised. We report a single laboratory experience using a real-time reverse transcription PCR (RT-qPCR) multiplex assay to detect genetic alterations in 9 genes relevant to NSCLC management. RT-qPCR can yield more genomic information with less tissue and a lower cost per gene than multiple single assays. A rapid test turnaround time also favours multiplex RT-qPCR over next-generation sequencing platforms. Gene selection was based on availability of FDA-approved drugs targeting alterations in the EGFR, ALK, ROS1, BRAF, KRAS, HER2 and RET genes.

    Methods
    

    Between December 2018 to April 2020, 142 NSCLC specimens were analysed. DNA and RNA were extracted from formalin-fixed and paraffin-embedded (FFPE) samples and screened by RT-qPCR multiplex assay (AmoyDx®, China) to detect 118 hotspot mutations or fusions in ALK, ROS1, RET, EGFR, KRAS, BRAF, NRAS, HER2 and PIK3CA genes. Clinicopathologic data were retrospectively extracted from test request forms.

    Results
    

    Of 142 patients, were 73 male (51.4%). Median age was 63. 128 patients (90.1%) were from Hong Kong and 14 (9.9%) from Thailand. 107 (75.4%) NSCLC were adenocarcinomatous, and 24 (16.9%) were unclassified. 99 (69.7%) were stage IV, and missing for 27 (19.0%) of NSCLC. 74 (52.1%) were treatment-naïve, 28 (19.7%) had prior drug treatments; treatment status was unknown in 40 patients (28.2%). At least 60 patients (42.3%) had prior genotyping, and 35 (24.6%) had EGFR or ALK testing. Mutations were identified in 94 patients (66.2%), and the distribution is shown in Figure 1.

    Females were more likely to harbour a targetable mutation than males (78.3% vs 54.8%, p=0.004; OR: 2.970, 95% CI: 1.428-6.393). RET fusions (8.7% vs 0%, p=0.01) and EGFR mutations were more common in females (44.9% vs 27.4%, p=0.04; OR: 2.162, 95% CI: 1.091-4.203). KRAS mutations were more common in males (17.8 vs 5.8%, p=0.04; OR: 3.521, 95% CI: 1.074-10.25).

    

    Conclusion
    

    In this Asian NSCLC population, RT-qPCR multiplex assay detected targetable driver mutations in 93 patients (65.5%), excluding PIK3CA mutations. RET fusions (4.2%) and HER2 mutations (6.3%) were more prevalent than historically reported. Upfront genotyping using RT-qPCR multiplex assays should guide treatment in these patients.

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