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Walter Astorino



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    EP1.15 - Thymoma/Other Thoracic Malignancies (ID 205)

    • Event: WCLC 2019
    • Type: E-Poster Viewing in the Exhibit Hall
    • Track: Thymoma/Other Thoracic Malignancies
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
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      EP1.15-12 - Predictive Value of Percentage of KI 67 Expression in Bronchopulmonary Carcinoid Tumors (Now Available) (ID 1420)

      08:00 - 18:00  |  Author(s): Walter Astorino

      • Abstract
      • Slides

      Background

      Introduction The determination of Ki67 has not been shown to be useful in the diagnostic discrimination between typical (CT) and atypical (CA) carcinoid tumors. However, the biological behavior of these tumors is not homogeneous. Objective: to establish a Ki67 cut-off point for carcinoid tumors and to determine its prognostic implications in overall survival and disease-free survival in both histological subtypes.

      Method

      Material and methods: retrospective cohort on 106 patients with diagnosis of carcinoid tumor (OMS 2015) surgically trated. The% of cells expressing Ki 67 was determined manually by two pathologists specialized in the use of a rabbit monoclonal antibody prediluted anti Ki67 (Clone MIB-1). Ki67-positive nuclei were quantified in 2000 consecutive tumor cells in the areas of highest activity (HOT SPOT) at a magnification of 40X. The comparison of continuous variables was made according to its distribution and the categorical variables with the Chi2 test or Fisher's exact test. To evaluate the association between Ki-67 expression and the occurrence of events, logical regression analysis was performed and ROC curves were constructed to evaluate global predictive capacity as per histological subtype, identifying the best cut-off point using the Youden index. Once this point was identified, the regression analysis was repeated using Ki-67 as a dichotomous variable (equal or greater than the cut-off point versus lower). All tests are two-tailed and a value of p <0.05 was considered statistically significant. The analysis was carried out with the program R: A Language and Environment for Statistical Computing version 3.5.1 (Vienna, Austria)

      Result

      Results: The data of ki-67 were available in 63/106 patients (59.4%). 40 (65.6%) CT and 23 (34.4%) CA. The 60.3% (n = 38) were women, the average age was 43.7 (SD 15.4) years, 25 (28.8%) were smokers. The median of ki-67 was 0.86 (RIQ 0.50 - 3.25). The presence of lymph node metastases N2 (12.8% vs 38.1%, p = 0.045), recurrence rate (2.5% vs 19%, p = 0.044) and mortality (0 vs 28.6%, p = 0.005) were significantly higher in the group of the CA. The median of ki-67 between the CTs was 0.63 (RIQ 0.44 - 1-93) vs 2.00 (RIQ 0.65 - 4.00) in CA (p = 0.005).The Ki-67 value was not significantly associated to mortality (p = 0.546), nor to risk of relapse, analyzing the entire population (p = 0.489), nor by histological subtype (CT p = 0.677 vs CA p = 0.202). The best cut-off point of Ki-67 on the ROC curve in patients with CA was 1.18. Using this value as a predictive variable, there was no significant association between% Ki-67 and mortality (p = 0.077), but a marginal association with the frequency of relapses (p = 0.054).

      Conclusion

      Conclusions: Although we have not been able to demonstrate predictive association between KI 67 and mortality, this could be due to the small number of observed events. In the AC subgroup, the marginal association between relapse frequency and Ki 67 values> = to 1.18 presents clinical relevance and future analyzes are required to determine the real predictive value of this variable.

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