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S. Park



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    Poster Display Session (ID 63)

    • Event: ELCC 2017
    • Type: Poster Display Session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 5/07/2017, 12:30 - 13:00, Hall 1
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      103P - Re-biopsy for advanced non-small cell lung cancer after EGFR tyrosine kinase inhibitor therapy: CT characteristics of patients with T790M mutation and the use of various re-biopsy procedures (ID 385)

      12:30 - 13:00  |  Author(s): S. Park

      • Abstract

      Background:
      Re-biopsy for mutation analysis of non-small cell lung cancer (NSCLC) after EGFR-tyrosine kinase inhibitor treatment is important to determine further chemotherapy regimen. There have been no studies about the radiologic characteristics of NSCLC with T790 mutation and the use of the various re-biopsy procedures.

      Methods:
      Between January and December 2016, 78 patients underwent re-biopsy for mutation analysis of NSCLC, and among them, 76 were assessed with adequate specimen. Patients’ treatment course, serial CT scans and pathologic reports were retrospectively reviewed. Re-biopsy methods are varied: EBUS or BFS-guided (n = 27), CT-guided (n = 18), fluoroscopy-guided (n = 5) biopsies, US-guided supraclavicular lymph node (n = 6) or other sites (n = 6) biopsies and pleural fluid analysis (n = 14). CT images obtained at the time of initial biopsy and re-biopsy were compared between patients with and without T790M mutation. Re-biopsy associated complications were assessed.

      Results:
      Among 76 patients, 40 (52.6%) presented T790M mutation on re-biopsy. Progression free survivals between patients with and without T790M mutation were not statistically different (322 and 389 days, respectively). On initial CT, pleural retraction (odds ratio (OR), 4.1; p = 0.03) and the presence of pleural metastasis (OR, 3.4; p = 0.03) were significant factors that related to the positive T790M mutation by multivariate logistic analysis. Pleural retraction (OR, 26.8, p = 0.03) and pleural metastasis (OR, 11.4; p = 0.004) are also shown as significant factors that related to the positive T790M mutation on CT obtained at the time of re-biopsy. Three patients developed pneumothorax, and two were managed by chest tube insertion. One patient who was negative T790M mutation on pleural fluid analysis finally diagnosed as positive T790M mutation by following CT-guided biopsy.

      Conclusions:
      Pleural retraction and pleural metastasis were significantly associated factors to positive T790M mutation in NSCLC patients who underwent re-biopsy. Negative T790M on pleural fluid analysis could not give a guarantee for true negative, and further core biopsy might be recommended.

      Clinical trial identification:


      Legal entity responsible for the study:
      None

      Funding:
      N/A

      Disclosure:
      All authors have declared no conflicts of interest.