Author of

• 12791

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  P3.19 - Poster Session 3 - Imaging (ID 181)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Imaging, Staging & Screening
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12801

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    P3.19-010 - The Status of EGFR Mutations in Mixed Ground-Glass Opacity (part-solid GGO) on Thin-section CT (ID 1826)

    09:30 - 09:30  |  Author(s): H. Saito
    • Abstract

    Background
    Thin-section CT (TS-CT) provides us with a more precise image of small pulmonary carcinomas. Thin-slice sections with thicknesses of 0.5 mm-1mm reflect, with some accuracy, the histopathological findings; mixed ground-glass opacity (part-solid GGO) is one characteristic finding of pulmonary adenocarciomas. These findings are vary in appearance, for example; some contain mainly GGO components, and some contain mainly solid portions. CT findings of mixed GGO, pathological findings and prognoses have been reported. Presently, we do not fully understand the correlation between TS-CT findings of mixed GGO and the status of EGFR mutation.

    Methods
    We retrospectively reviewed the records and TS-CT scans of 115 patients with mixed GGO tumors. All patients had undergone surgical resection between 2002 and 2008. Tumor diameters measured 20mm or less in size. All TS-CT images were acquired by Aquillion CT scanner (Toshiba Medical System). TS-CT images of tumors were obtained at 135kVp at 250mAs with 0.5-1mm section thickness. All images were photographed using mediastinal (level, 40HU; width, 400HU) and lung (level, -600HU); width, 1600HU) window settings. All TS-CT images on lung window setting were classified as: (1) Predominant GGO type (pGGO; solid portion areas less than 50% of tumor), (2) Heterogeneous type (heterogenous increased density), (3) Predominat solid type (pSolid; Solid portion areas took up more than 50% of tumor). We analyzed EGFR and Kras mutations, and then studied the correlations between these TS-CT findings and the status of EGFR mutations.

    Results
    The tumors in all 115 cases were well-differentiated adenocarcinomas. GwS type; 24 cases, Heteogenous type; 30 cases, and SwG type 61 cases. The EGFR mutation ratio was 66.6% in pGGO type, 90% in Heterogenous type and 52.7% in pSolid type. The ratio of EGFR mutation was greater in Heterogenous types compared to pGGO and pSolid types. (pGGO/Hetero p=0.045, pSolid/Hetero p=0.00038).

    Conclusion
    There is a correlation between the thin-section findings of mixed GGO and the status of EGFR mutations.