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T.Y. Chou
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P3.01 - Poster Session with Presenters Present (ID 469)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Biology/Pathology
- Presentations: 2
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.01-009 - A Prospective Study of 'Spread through a Knife Surface' (STAKS) in Non-Small Cell Lung Cancer Resection Specimens (ID 4694)
14:30 - 14:30 | Author(s): T.Y. Chou
- Abstract
Background:
An extraneous tissue contaminant on a slide is called a floater. Spread Through Air Spaces (STAS) is in the WHO classification considered as a form of invasion in lung adenocarcinoma. The artifactual spread of tissue fragments during lung specimen sectioning was recently described and termed Spreading Through A Knife Surface (STAKS).1 The purpose of this study was to prospectively examine lung resection specimens for the presence and frequency of STAKS.
Methods:
A prospective, multi-institutional study of NSCLC lobectomy and pneumonectomy resection specimen was performed from January 1 –July 1, 2016. Prosection, sampling and scoring of displaced fragments was undertaken in a systematic manner. The first cut was made with a clean long knife, the second cut was made in a parallel plane to the first cut, without cleaning the knife. Four tissue blocks were sampled: Block 1: first cut, upper part; Block 2: first cut, lower part; Block 3: second cut, upper part; Block 4: second cut, lower part. From these formalin fixed and paraffin embedded tissue blocks a superficial complete H&E stained slide was examined for the presence of displaced tissue fragments at 10x or 20x. A displaced fragment was scored as STAKS if the tissue fragment was at least 0.5 mm from the tumor or if it was on the pleural surface in the plane of the second cut. Benign and malignant STAKS were separately noted.
Results:
A total of 41 resection specimen were included in this study. The mean number of malignant STAKS for blocks 1-4 was 0.36, 1.44, 1.86 and 1.95, respectively and for benign STAKS the mean number was 0.11, 0.11, 0.13 and 0.25, respectively. Almost all STAKS were intra-alveolar. Comparison of malignant STAKS in block 1 (before the tumor was reached) with blocks 2-4 (containing tumor) was significant with p-values (p=0.003 Friedman’s test and post-hoc comparisons p=0.031, p=0.002 and p=0.005, respectively). For benign STAKS no difference was identified (p=0.23). The chance of malignant STAKS seemed to be higher when tumor was cut fresh than when cut after formalin fixation.
Conclusion:
The morphologic definition of STAKS is not different from STAS. This prospective study confirms the presence of benign and malignant STAKS. The presence of malignant STAKS is an artifact and increases with each and every knife cut during tissue sectioning. 1) Thunnissen et al. ArchPatholLabMed2016,140(212-220)
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P3.01-021 - Reproducibility of Comprehensive Histologic Assessment and Refining Histologic Criteria in P Staging of Multiple Tumour Nodules (ID 5365)
14:30 - 14:30 | Author(s): T.Y. Chou
- Abstract
Background:
Multiple tumor nodules (MTNs) are being encountered, with increasing frequency with the 8[th] TNM staging system recommending classification as separate primary lung cancers (SPLC) or intrapulmonary metastases (IM). Pathological staging requires assessment of morphological features, with criteria of Martini and Melamed supplanted by comprehensive histologic assessment of tumour type, predominant pattern, other histologic patterns and cytologic features. With publication of the 2015 WHO classification of lung tumours, we assessed the reproducibility of comprehensive histologic assessment and also sought to identify the most useful histological features.
Methods:
We conducted an online survey in which pathologists reviewed a sequential cohort of resected multifocal tumours to determine whether they were SPLC, IM, or a combination. Specific histological features for each nodule were entered into the database by the observing pathologist (tumour type, predominant adenocarcinoma pattern, and histological features including presence of lepidic growth, intra-alveolar cell clusters, cell size, mitotic rate, nuclear pleomorphism, nucleolar size and pleomorphism, nuclear inclusions, necrosis pattern, vascular invasion, mucin content, keratinization, clear cell change, cytoplasmic granules¸ lymphocytosis, macrophage response, acute inflammation and emperipolesis). Results were statistically analyzed for concordance with submitting diagnosis (gold standard) and among pathologists. Consistency of each feature was correlated with final determination of SPLC vs. IM status (p staging) by chi square analysis and Fisher exact test.
Results:
Seventeen pathologists evaluated 126 tumors from 48 patients. Kappa score on overall assessment of primary v. metastatic status was 0.60. There was good agreement as measured by Cohen’s Kappa (0.64, p<0.0001) between WHO histological patterns in individual cases with SPLC or IM status but proportions for histology and SPT or IM status were not identical (McNemar's test, p<0.0001) and additional histological features were assessed. There was marked variation in p values among the specific histological features. The strongest correlations (<0.05) between p staging status and histological features were with nuclear pleomorphism, cell size, acinus formation, nucleolar size, mitotic rate, nuclear inclusions, intra-alveolar clusters and necrosis pattern. Correlation between lymphocytosis, mucin content, lepidic growth, vascular invasion, macrophage response, clear cell change, acute inflammation keratinization and emperipolesis did not reach a p value of 0.05.
Conclusion:
Comprehensive histologic assessment shows good reproducibility between practicing lung pathologists. In addition to main tumour type and predominant patterns, nuclear pleomorphism, cell size, acinus formation, nucleolar size, and mitotic rate appear to be useful in distinguishing between SPLC and IM.
