2023 World Conference on Lung Cancer (Posters)-EP13.01. Mitotic Counts and Phospho-Histone H3 Index in Grading Pulmonary Neuroendocrine Tumors: Assessment of Interobserver Variability and Utility

EP13.01. Mitotic Counts and Phospho-Histone H3 Index in Grading Pulmonary Neuroendocrine Tumors: Assessment of Interobserver Variability and Utility - PDF(Abstract)

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This study aimed to assess the value of phospho-histone H3 (PHH3) immunohistochemistry in grading pulmonary neuroendocrine tumors. Pulmonary neuroendocrine neoplasms, including typical carcinoid (TC) and atypical carcinoid (AC), are differentiated based on mitotic counts and/or the presence of tumor necrosis in AC. However, the identification of mitotic figures (MF) is subject to interobserver variability and sampling bias, and is time-consuming. PHH3 is a protein expressed during the mitotic phase and can serve as a surrogate marker for MFs. The researchers hypothesized that the addition of PHH3 and the use of digital image analysis can improve the interobserver reproducibility in grading typical versus atypical carcinoids.<br /><br />The study included thirty resection specimens with lung neuroendocrine tumors. The mitotic counts showed considerable variation, with an intraclass correlation coefficient of 0.3498 (single measures) and 0.6175 (average measures). The average time taken by the pathologists for scanning the section for mitotic counts was 20 minutes. For PHH3 stained sections, there was near-perfect agreement among the pathologists, with an intraclass correlation coefficient of 0.9814 (single measures) and 0.9937 (average measures). The average time taken for scanning the section for PHH3 counts was 5 minutes at low power magnification.<br /><br />The correlation between manual mitotic counts and manual PHH3 counts was moderate, with a correlation coefficient of 0.376. The correlation between manual mitotic counts and Ki-67 labelling indices showed weak correlation for both. Additionally, up to one-third of cases showed a change in grading depending on whether H&E mitotic counts or PHH3 mitotic counts were used.<br /><br />Based on the results, the researchers concluded that PHH3 mitotic counts are a faster and more efficient alternative to manual mitotic counts in pulmonary neuroendocrine tumors, with excellent interobserver agreement. The use of PHH3 and digital image analysis can potentially improve the reproducibility and accuracy of grading pulmonary neuroendocrine tumors.

Asset Subtitle

Somagattu Sushmitha

Meta Tag

Speaker Somagattu Sushmitha

Topic SCLC & Neuroendocrine Tumors: Biomarkers & Radiomics

Keywords

phospho-histone H3

PHH3

immunohistochemistry

grading

pulmonary neuroendocrine tumors

typical carcinoid

atypical carcinoid

mitotic counts

interobserver reproducibility

digital image analysis