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H. Blaauwgeers
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P3.01 - Poster Session with Presenters Present (ID 469)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- 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): H. Blaauwgeers
- 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)
