Author of

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  P52 - Staging - Prognosis and Staging (ID 186)

  • Event: WCLC 2020
  • Type: Posters
  • Track: Staging
  • Presentations: 1
  • Moderators:
  • Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall

  • 35697

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    P52.03 - Concordance of PET Scan and EBUS-TBNA for Mediastinal Staging of Stage 3 Non-Small Cell Lung Cancer (ID 1593)

    00:00 - 00:00  |  Presenting Author(s): Marie-Philippe Saltiel
    • Abstract
    • Slides

    Introduction
    

    Mediastinal staging is essential to plan adequate treatment for patients with stage 3 non-small cell lung cancer (NSCLC). Curative-intent radiation fields are often planned based on positron-emission tomography (PET) scan results, despite the fact that this imaging modality has limitations. Endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA) has been shown to have higher sensitivity and specificity. The objective of this study is to evaluate the concordance of PET scan and EBUS-TBNA in mediastinal staging.

    Methods
    

    We conducted a retrospective cohort study of patients diagnosed with NSCLC at Sunnybrook Health Sciences Centre, Toronto, Canada, between September 2017 and November 2019. From an institutional database of all lung cancer patients who underwent EBUS-TBNA for lung cancer, patients with stage 3 NSCLC with both EBUS-TBNA and PET scan for mediastinal staging were included. EBUS results were considered the gold standard for nodal staging based on previous publications. Indeterminate PET scan results were reviewed independently by a PET radiologist. Analyses of sensitivity and specificity were conducted on a per-node basis.

    Results
    

    Thirty-two patients were included in the analysis. The median number of nodes biopsied per patient was 3 (range 1- 5). Ten patients (31%) had at least one discordant lymph node station. The sensitivity and specificity of PET scan were 78.7% and 79.3%, respectively. Six positive lymph nodes on PET scan were downstaged by EBUS-TBNA, including a patient who was downstaged from cN2 to pN0. The five patients with false positive results did not have any known inflammatory or infectious disease at the time of the PET study. Ten lymph node metastases in five patients were PET-occult. Two patients were upstaged from cN2 to pN3, and one from cN0 to pN2. The size of PET-occult metastases compared to false positive lymph nodes was not significantly different (p=0.65). Seventeen patients (65%) went on to be treated with concurrent chemoradiation, and 6 had radical-intent radiation only. Other patients were treated with chemotherapy only (n=1), targeted therapy (n=3), or lost to follow-up (n=5).

    Conclusion
    

    Our study shows there is clinically significant discordance in the extent of nodal metastases between PET scan and EBUS-TBNA among patients with stage 3 NSCLC. Routine systematic EBUS-TBNA may improve radiation treatment planning by including all affected areas while sparing disease-free lymph nodes. This reinforces the recommendation that patients with high risk of N2 or N3 disease should get mediastinal staging prior to definitive therapy. The impact of discordant results on radiotherapy treatment plans will be reviewed in the next phase of our study.

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