Author of

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  P2.12 - Small Cell Lung Cancer/NET (ID 180)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Small Cell Lung Cancer/NET
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31427

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    P2.12-23 - Radiological Features of SCLC-Like and NSCLC-Like Large Cell Neuroendocrine Carcinoma (LCNEC) (ID 1587)

    10:15 - 18:15  |  Presenting Author(s): Bregtje Catharina Maria Hermans
    • Abstract
    • Slides

    Background
    

    Large cell neuroendocrine carcinoma (LCNEC) can be divided in two pathological subtypes: the SCLC-like LCNEC with RB1 mutations/loss of RB1 staining and the NSCLC-like LCNEC with preserved RB1 staining. The radiological presentations of NSCLC and SCLC are different, with SCLC mainly presenting with bulky disease and a central tumor. Here, we investigated if a distinction between SCLC-like and NSCLC-like LCNEC can be made based on radiological features.

    Method
    

    A survey was developed with chest CT-scans and X-rays of patients with pathological confirmed stage-IV LCNEC (N=52). For reference, images of 10 SCLC and 10 NSCLC patients were randomly included. The survey was distributed among oncology pulmonologists in the Netherlands. Responders could score images as ‘SCLC-like’, ‘NSCLC-like’ or ‘not possible to determine (nptd)’. Cases were considered as SCLC-like if no more than 1 responder scored NSCLC-like and no more than 67% scored ‘nptd’. A similar approach was used to classify NSCLC-like cases. Images not fulfilling both approaches were regarded not applicable (NA).

    Result
    

    The survey was completed by 23 pulmonologists with >5 years of experience, of which 12 had >15 years of experience. 90% NSCLC reference CT-scans were correctly classified, in contrast to only 30% correctly classified SCLC CT-scans (Table). For 36/52 LCNEC RB1 immunohistochemical status was known; 9/36 were RB1 positive and 27/36 RB1 negative. In RB1 positive LCNEC 6/9 scans were allocated to the NSCLC-like group. In RB1 negative LCNEC 2/27 scans were allocated to the SCLC-like group and 17/27 to the NSCLC-like group. If the scan was assessed as SCLC-like, RB1 was negative in 100% of cases. However, in cases assessed as NSCLC-like, only 26% was RB1 positive. No distinction between SCLC-like and NSCLC-like LCNEC could be made based on X-rays (Table).

    

    Conclusion
    

    In LCNEC, a CT-scan assessed as SCLC-like is highly predictive for RB1 negative status, whereas a NSCLC-like CT-scan can be both of the RB1 negative and positive subtype. During WCLC results including RB1 status of all 52 LCNEC will be presented.

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