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R.J. Van Suylen
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P1.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 224)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.08-024 - Large Cell Neuroendocrine Carcinoma: How Accurate Are the WHO 2004 Classification Criteria Applied? (ID 2127)
09:30 - 09:30 | Author(s): R.J. Van Suylen
- Abstract
Background:
According to the WHO 2004 (and 2015) classification, the diagnosis large cell neuroendocrine carcinoma (LCNEC) is established on presence of neuroendocrine morphology (i.e. organoid nesting/trabecular pattern, palisading cells and/or rosette formation) and neuroendocrine staining by immunohistochemical (IHC) markers. Furthermore, large cells should be present. However, diagnosis of LCNEC is restrained by the need of a resection or large biopsy specimen. Nonetheless, lung cancer is often diagnosed on small biopsies and therefore application of these WHO criteria in daily practice can be difficult. In this nationwide study we investigate on what tissue the diagnosis of LCNEC was established and to what extend the WHO 2004 criteria are reported in pathology reports established in the daily pathology practice in the Netherlands.
Methods:
Written conclusions (diagnoses) of pathology reports (2003-2012) were retrieved from the Dutch Pathology Registry (PALGA). Conclusions describing LCNEC were selected by queries on anatomic location, diagnosis and keywords (e.g. large cell + endocrine) and screened in accordance with a pathologist (JLD & RJS). Histologically diagnosed LCNEC cases were then selected and pathology centers were requested to send the report. After screening (JLD), consultation reports were excluded and the following data were extracted and compared: 1) mitotic index, 2) necrosis, 3) growth pattern (reported ≥1 feature(s) according to WHO or mentioning neuroendocrine morphology) and 4) neuroendocrine IHC marker staining. Additionally, the sampling method was recorded and retrieved diagnoses were clustered.
Results:
N=892 (72%) of 1235 requested reports were received (43 centers, mean 20 (range 1-67) reports). In N=869 pathology reports the conclusion was LCNEC including 759 original and 110 consultation reports. Most diagnoses were established on resection specimens (N=404, 53%) followed by needle (N=195, 26%) and small biopsies (N=160, 20%). Retrieved diagnoses could be clustered into LCNEC (N=658, 87%), combined LCNEC (N=41, 5%) and carcinoma favor LCNEC (N=60, 8%) respectively. Presence of mitoses was reported in N=541 (71%) yet only N=121 (16%) mentioned the mitotic index (≥10 mitoses 2mm[2] N=107). Necrosis was described in N=466 (61%) reports, most had central/abundant necrosis N=317 (68%) but in N=84 (11%) necrosis was undefined. Neuroendocrine morphology or a feature of neuroendocrine morphology was described in N=452 (60%) reports and in all except N=13 reports a neuroendocrine IHC marker was positive. When combining the WHO criteria, only N=66 (9%) of reports described all criteria, this increased to N=253 (33%) when mitosis without description of an index was included and N=403 (53%) if the report described either mitosis or necrosis. Lowest reported rates were observed in reports of needle biopsy (8-27%) and biopsy (4-15%) specimens.
Conclusion:
In 91% of retrieved pathology reports the WHO criteria for the diagnosis LCNEC could not be retrieved. Although 53% of reports included descriptions of neuroendocrine growth pattern and mitosis or necrosis, these regularly were incomplete or not quantifiable. Most commonly this was observed in reports from (needle) biopsy specimens. Whether the WHO criteria could not be established or if it is due to preference of the pathologist remains unclear and requires further investigation. Nevertheless, implementation of structured pathology reporting protocols for LCNEC should be considered.
