Author of

• 11866

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  P2.18 - Poster Session 2 - Pathology (ID 176)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11880

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    P2.18-014 - Impact of Non Small Cell Lung Cancer (NSCLC) immunophenotyping in chemotherapy response. (ID 2679)

    09:30 - 09:30  |  Author(s): J. Giorcelli
    • Abstract

    Background
    The vast majority of non small cell lung cancers (NSCLC) presents as advanced disease and histological diagnosis is widely based on small biopsy or cytological samples. Recently, the adoption of new pharmaceutical agents targeting individual histotypes requires a precise subtyping of NSCLC. This task is often difficult according to morphological criteria only and the use of immunohistochemistry (IHC) is recommended for small samples or undifferentiated tumors to define the most probable histotype. However, the real impact of IHC characterization of NSCLC-Not otherwise Specified (NOS) in terms of response to therapy and outcome (compared to cases classified by morphology, only) is not well established.

    Methods
    A large series of 224 advanced "non-squamous" NSCLC diagnosed from year 2005 to 2010 on small biopsy or cytological samples and homogeneously treated, was retrospectively selected, all with adequate follow-up data available. All diagnoses were reviewed resulting in two groups of adenocarcinoma (ADC) and NSCLC-NOS. The latter were further characterized by IHC to identify the most probable differentiation lineage. Disease Control Rate (DCR) and Response Rate (RR) were calculated and Overall Survival (OS) curves were analyzed by Kaplan Meier.

    Results
    After review 120/224 (53.6%) cases were ADC based on morphological examination, only (“ADC morphology”) and 104/224 (46.4%) remained NSCLC-NOS. In terms of response to therapy no significant difference was found between the two groups (“ADC morphology” had DCR= 0.66 and RR=0.31; NSCLC-NOS had DCR=0.64 and RR=0.35; Chi-Square p=0.83). The NSCLC-NOS cases that underwent IHC profiling resulted in 66/104 (63.5%) cases that had an ADC phenotype (“NSCLC favor ADC”) and 38/104 (36.5%) cases that lack ADC features (including 5 “NSCLC favor squamous carcinoma” and 33 “NSCLC null phenotype”). The “NSCLC favor-ADC” had DCR and RR similar to “ADC morphology” group (Chi-Square p=0.23), while the “non-ADC” NSCLC group had significantly different both DCR=0.47 and RR=0.29 (Chi-Square p=0.006). Survival curves confirmed no difference in terms of survival between the “ADC morphology” and the “NSCLC favor-ADC” groups, while showed a significantly poorer survival for the “non-ADC” NSCLC group with respect the other two groups (median survival: 8.5 vs 12.3 months, respectively; HR=0.5999; p=0.018).

    Conclusion
    These preliminary findings indicate that the practice of minimizing the NSCLC-NOS diagnoses by means of IHC has an impact on chemotherapy response. Stratifying such tumors by IHC, cases having an ADC immunoprofile had response rates comparable to those of morphologically diagnosed ADC, thus supporting the value of IHC to maximize lung cancer histological typing in the perspective of obtaining the best response to therapy.