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B. Maksymiuk

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    P1.02 - Biology/Pathology (ID 614)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Biology/Pathology
    • Presentations: 1
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      P1.02-037 - Pulmonary Carcinoid Tumors: A Prognostic Implications of Ki-67 Proliferative Index (ID 9873)

      09:30 - 16:00  |  Author(s): B. Maksymiuk

      • Abstract

      Division of typical (TC) and atypical (AC) carcinoids is based on the mitotic index and/or the presence of necrosis. A mitotic rate is a well-established and highly prognostic factor, but many studies indicate that assessment of proliferative activity based on Ki-67 value could be easier and more reproducible. The aim of the study was: •assessment of Ki-67 index in PC and its usefulness in distinguishing TC from AC, •to determine whether the mean Ki-67 index is significantly different in TC and AC, •selection the optimal cut-off Ki-67 value that would help predict overall survival in pulmonary carcinoids (PC).

      The clinicopathological features from 329 resected PC were correlated and survival analysis were performed. Mitoses and the proliferative index (PI) were analyzed. For mitotic counting, a scale bar depicting an area of 2 mm[2 ]was provided and for PI assessment, the percentage of positively stained cells by Ki-67 in the area with the highest proliferative activity was counted.

      There were 217 (66%) TC and 112 (34%) AC, with a median follow-up time of 7,6 ys (230 females and 99 males). The mean age at diagnosis was 52,8 years, median 55 y. Most tumors were localized centrally (73,7%). AC were larger than TC (2,54 vs 1,9cm) and more common located peripherally. Lymph nodes involvement was present in 49 cases (15%), N1-34 (10%) and N2-15 (5%), frequently in AC.The high cellular atypia, cartilage destruction, invasion of peribronchial tissue or adjacent lung parenchyma, presence of pleural, perineural and vascular invasion correlated with AC. ACs were associated with significantly higher Ki-67 indices (8,7%, median 7%) than TCs (3,1%, median 2%). There were significant correlations between high PI and: large tumor size, mitotic activity, vascular invasion and lymph node metastases.The Ki-67 index was a good factor differentiating TC from AC, with cut-off ≤ 4% for TC and > 4% for AC, with high specifity (90%) and sensitivity (70%) and with high likelihood ratio (2,97).The number of deaths among the patients with TC and AC was 7 (6,3%) and 31 (14,3%) respectively. The 5-,10- and 15 year overall survivals for the entire group were 92,8%, 86,8% and 78,6% respectively.

      Ki-67 is an effective grading tool for PC and for differentiation between TC from AC. Apart the mitotic count and necrosis, the Ki-67 index should be incorporated into the mandatory histological criteria for diagnosis PC. The optimal cut-off value of Ki-67 that helps distinguish TC from AC is 4%.