Author of

• 31780

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  P2.17 - Treatment of Early Stage/Localized Disease (ID 189)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Treatment of Early Stage/Localized Disease
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31825

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    P2.17-39 - Relationship Between EGFR Mutation and Pathological Differentiation in Patients with Clinical Stage IA Lung Adenocarcinoma (ID 3008)

    10:15 - 18:15  |  Presenting Author(s): Junichiro Osawa
    • Abstract

    Background
    

    Pathological differentiation is an established prognostic factor for patients with lung

    adenocarcinoma. There are some correlations between epidermal growth factor receptor

    (EGFR) mutations and pathological differentiation. EGFR mutation-positive

    adenocarcinoma is considered to be highly differentiated types that show development

    of alveolar epithelial substitution. However, the distribution of pathological

    differentiation and the prognostic impact of the presence or absence of EGFR mutations

    in early adenocarcinoma are not clear.

    Method
    

    We collected the records of 569 patients who underwent surgical resection for clinical

    stage ⅠA lung adenocarcinoma between 2008 and 2015, and were also examined their

    EGFR mutation status.

    Based on the presence or absence of EGFR mutations and pathological differentiation

    (well;G1/moderately;G2/poorly;G3), patients were categorized into 6 groups: EGFR

    mutation positive (E+) with G1, E+ with G2, E+ with G3, EGFR mutation negative (E-)

    with G1, E- with G2, E- with G3. We examined the distribution of each group,　

    clinicopathological features and prognosis.

    Result
    

    303 lung adenocarcinoma had EGFR mutations. The distribution was

    E+/G1:85,E+/G2:209,E+/G3:9,E-/G1:50,E-/G2:178,E-/G3:38. E+/G3 group was

    significantly fewer (P<0.001). The 5-year recurrence-free survival (RFS) rates were

    95% in E+/G1 group, 78% in E+/G2 group, 33% in E+/G3 group, 100% in E-/G1

    group, 75% in E-/G2 group, 61% in E-/G3 group. The 5-year overall survival (OS) rates

    were 98% in E+/G1 group, 91% in E+/G2 group, 44% in E+/G3 group, 100% in E-/G1

    group, 87% in E-/G2 group, 79% in E-/G3 group. The prognosis was significantly

    worse in the E+/G3 group. There were more women (77%) and non-smokers (89%) in

    the E+/G3 group. Six patients (66%) had recurrence, and in all cases EGFR-TKI was

    administered and the response rate was 100%.

    Conclusion
    

    Most of the c-IA EGFR positive adenocarcinomas were highly differentiated, and

    significantly fewer poorly differentiated cases. Among the poorly differentiated group,

    EGFR gene mutation positive is particularly poor prognosis. However, The therapeutic

    effect of EGFR-TKI was not different from other EGFR positive patients.