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Natasha Rekhtman



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    MA 15 - Lung Cancer Biology II (ID 670)

    • Event: WCLC 2017
    • Type: Mini Oral
    • Track: Biology/Pathology
    • Presentations: 1
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      MA 15.10 - Discussant - MA 15.06, MA 15.07, MA 15.08, MA 15.09 (ID 10775)

      15:45 - 17:30  |  Presenting Author(s): Natasha Rekhtman

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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    OA 18 - Lung Cancer Pathology and Genetics (ID 687)

    • Event: WCLC 2017
    • Type: Oral
    • Track: Biology/Pathology
    • Presentations: 1
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      OA 18.06 - Three-Dimensional Assessment of Spread Through Air Spaces in Lung Adenocarcinoma: Insights and Implications (ID 8826)

      14:30 - 16:15  |  Author(s): Natasha Rekhtman

      • Abstract
      • Presentation
      • Slides

      Background:
      Tumor spread through air space (STAS) is a newly recognized form of invasion in lung adenocarcinoma and squamous cell carcinoma and growing evidence shows it is associated with recurrence and survival. The observation that tumor STAS clusters/nests or single cells within air spaces on two-dimensional H&E slides raised the question of how these cells could survive within air spaces without a vascular supply and this has led some to speculate STAS is an artifact. Herein, we perform the high resolution-high quality 3D reconstruction and visualization of normal lung and tumor in a lung adenocarcinoma to investigate the invasive pattern of STAS.

      Method:
      A formalin-fixed paraffin embedded block of invasive adenocarcinoma with micropapillary pattern and extensive STAS was studied. Following our histology 3D reconstruction standard procedure, 3D reconstruction was performed for analysis from 200 serial sections of H&E stained 20x (0.5um/pixel resolution) whole slide images. The relationship to alveolar walls between micropapillary structures within the tumor and STAS clusters in lung parenchyma distant from the tumor was evaluated.

      Result:
      3D reconstruction and analysis demonstrated the following novel features – a) in the main tumor area, micropapillary structures within airspaces were connected to alveolar walls, b) unlike in 2D evaluation where STAS appeared as ‘free-floating’ micropapillary clusters, in 3D evaluation many STAS clusters within air spaces are attached to alveolar walls, and c) STAS clusters that appear ring-like in 2D by 3D evaluation they are actually balls of tumor cells surrounding a central space.

      Conclusion:
      Our 3D reconstructed image analysis for the first-time demonstrates that most STAS cells are not ‘free-floating’, rather attached to the alveolar walls. In addition within the main tumor micropapillary clusters are attached to alveolar walls. These findings raise an intriguing hypothesis that STAS cells are clusters of tumor cells spread within alveolar spaces in a non-contiguous fashion to reattach to the alveolar walls at a distance possibly by co-option of alveolar wall capillaries to support their growth. This form of spread is analogous to the phenomenon of vascular spread where tumor cells spread freely within blood vessels to distant sites where they attach to endothelium and extravasate through the vessel walls to form metastases. It is possible the ball-like configuration of STAS clusters may facilitate movement through alveolar spaces distant from the main tumor. The frequent alveolar wall attachment of STAS observed on serial 3D imaging disputes the concept this is an artifact.

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    P3.13 - Radiology/Staging/Screening (ID 729)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Radiology/Staging/Screening
    • Presentations: 1
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      P3.13-019 - Preoperative Needle Biopsy Does Not Increase the Risk of Pleural Recurrence in ≤3cm Lung Adenocarcinoma (ID 9526)

      09:30 - 16:00  |  Author(s): Natasha Rekhtman

      • Abstract

      Background:
      Percutaneous transthoracic needle biopsy (NB) has been widely used for the preoperative diagnosis of lung nodules. It has been proposed that the risk of pleural recurrence is high following lung resection in patients who underwent preoperative NB for sub-pleural nodules (Kashiwabara, et al. Cancer Invest 2016; Wang, et al. Sci Rep 2017). The aim of this study is to investigate the prognostic impact of preoperative NB for pleural recurrence in patients with early-stage lung adenocarcinoma (ADC).

      Method:
      Patients who underwent lung resection for pathologic stage I (≤3cm) lung ADC were included in the analysis (1995-2014, n=992; NB group 626 patients and no-NB group 366 patients). We compared the clinicopathologic characteristics and recurrence free probability (RFP, separately analyzed for any, locoregional, pleural, and distant recurrence) between NB and no-NB groups. The risk of pleural recurrence was evaluated in tumors both with and without visceral pleural invasion (VPI).

      Result:
      The NB cohort was associated with older age and larger tumor size compared to the no-NB cohort (p<0.05). There was no statistical difference in the incidence of VPI (VPI in NB, 12% vs. VPI in non-NB, 15%, p=0.2). In RFP analysis by Kaplan-Meier method with log-rank test, there was no statistical difference between NB and no-NB groups (NB vs. non-NB: 5-year RFP for any recurrence, 86% vs. 86%, p=0.8; locoregional recurrence, 93% vs. 94%, p=0.7; pleural recurrence, 98% vs. 96%, p=0.14; and distant recurrence 94% vs. 93%, p=1). In tumors both with and without VPI (n=128 and n=864, respectively), the risk of pleural recurrence was not higher after NB (Figure; 5-year RFP for pleural recurrence [NB vs. no-NB]: VPI positive, 93% vs. 83%, p=0.3; VPI negative, 98% vs. 97%, p=0.4). Figure 1



      Conclusion:
      Preoperative needle biopsy was not associated with an increased risk of pleural recurrence following lung resection.