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R.J. Van Suylen
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P2.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 225)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.08-023 - Aberrant Neuroendocrine Lung Tumor Nomenclature in Daily Practice, How Common Is It? (ID 2120)
09:30 - 09:30 | Author(s): R.J. Van Suylen
- Abstract
Background:
The WHO 2015 classification for pulmonary carcinoids (PC) and high-grade neuroendocrine carcinomas (NEC) has in essence, not been changed compared to the previous one, despite known limitations in the diagnostic process such as 1) the need for resection material or large biopsies 2) reported inter-observer variability and 3) sporadic exposure in daily practice. Furthermore, nomenclature used in previous or different classification systems for neuroendocrine tumors may result in an aberrantly applied description of the WHO 2004 diagnoses. Here we evaluate if nomenclature established in daily pathology practice in the Netherlands is according to that advised by the WHO 2004 for PC, NEC and non-small cell lung cancer (NSCLC) with neuroendocrine differentiation established by immunohistochemistry (IHC).
Methods:
Written conclusions (diagnoses) of pathology reports (2003-2012) were retrieved from the Dutch Pathology Registry. Conclusions describing PC, NEC and carcinomas with neuroendocrine features/differentiation were selected by multiple queries on anatomic location, diagnosis and keywords (e.g. carcinoma + endocrine). All conclusions were screened in concordance with an experienced pathologist (JLD & RJS) and data on sampling method, diagnoses and origin of primary tumor were collected. Conclusions were excluded if established on autopsy cases or if it reported differential diagnoses, diagnoses of non-pulmonary/unknown primary, non-neuroendocrine or small cell lung cancer. We compared the retrieved diagnoses with the advised WHO 2004 nomenclature after which all diagnoses were clustered (e.g. typical/well differentiated/grade I carcinoid into “PC”). For statistical analysis the X[2] test was used.
Results:
4612 conclusions were eligible for analysis of which N=698 (15%) described a diagnoses that did not match the WHO nomenclature. Foremost non-WHO diagnoses were: (poorly differentiated) neuroendocrine carcinoma; high-grade neuroendocrine carcinoma/tumor; NSCLC neuroendocrine carcinoma; neuroendocrine tumor and low grade (well differentiated) neuroendocrine carcinoma/tumor (carcinoids). After discussion, we clustered N=2005 (43%) diagnoses into PC, N=1788 (39%) in high-grade NEC, N=763 (17%) in carcinoma with neuroendocrine features/differentiation and N=56 (1%) in neuroendocrine tumor n.o.s., respectively. Deviations from the WHO nomenclature occurred in 8% (N=157) of PC and 21% (N=377) of high-grade NEC and this occurred mainly on biopsy/cytology specimens (75% (N=399)). In (NSCLC) carcinomas with neuroendocrine features/differentiation diagnoses deviated from the WHO in 14% (N=108). Additionally, both the terms neuroendocrine “features” and “differentiation” were used to address positive neuroendocrine IHC staining (16% vs 25%) though differentiation was used slightly more often (p=0.001). Finally, 52% (N=1045) of PC diagnoses were established on biopsy/cytology specimens and a strong increase in diagnoses of large cell neuroendocrine carcinoma (LCNEC) on biopsy/cytology specimens was observed (<2008 N=174 vs. ≥2008 N=464, p<0.001).
Conclusion:
In daily practice 8% of PC, 21% of high-grade NEC and 14% of (NSCLC) carcinomas with neuroendocrine features/differentiation diagnoses deviated from the WHO 2004 nomenclature. This occurred mainly on biopsy/cytology specimens. Also, the diagnosis (NSCLC) carcinoma with neuroendocrine ‘differentiation/features’ was unclear and should be specified (i.e. IHC or morphologically based (or both)). Finally, often the diagnosis LCNEC was established on biopsy/cytology specimens whereas this is not advised by the WHO. Whether these findings are due to personal preferences or difficulties applying current classification to limited samples, require further investigation.
