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Medline ® Abstract for Reference 65

of 'Pathology, classification, and grading of neuroendocrine tumors arising in the digestive system'

Are G3 ENETS neuroendocrine neoplasms heterogeneous?
Vélayoudom-Céphise FL, Duvillard P, Foucan L, Hadoux J, Chougnet CN, Leboulleux S, Malka D, Guigay J, Goere D, Debaere T, Caramella C, Schlumberger M, Planchard D, Elias D, Ducreux M, Scoazec JY, Baudin E
Endocr Relat Cancer. 2013 Oct;20(5):649-57.
The new WHO classification of gastroenteropancreatic (GEP) neuroendocrine tumors (NET) implies that G3 neoplasms with mitotic index>20 and/or Ki67 index>20% are neuroendocrine carcinomas (NEC), described as poorly differentiated, small or large cell types, by analogy with lung NEC. To characterize the subgroup of non-small-cell-type GEP and thoracic NET with mitotic index>20 and/or Ki67>20% according to their pathological features, response to cisplatin and overall survival (OS). We reviewed pathological and clinical presentation of G3 non-small-cell-type NET referred to our institution for 5 years. Data from 166 patients with metastatic thoracic and GEP-NET were collected. Twenty-eight patients (17%) fulfill the inclusion criteria. Tumors were classified as well-differentiated NET (G3-WDNET) in 42.8% of cases and poorly differentiated, large-cell NEC (G3-LCNEC) in 57.2% of cases. Plasma chromogranin A or neuron-specific enolase were elevated in 42 and 25% respectively of G3-WDNET and 31 and 50% of G3-LCNEC. Somatostatin receptor scintigraphy was positive in 88 and 50% of G3-WDNET or G3-LCNEC respectively. Complete or partial response to cisplatin was observed in 31% of cases, all classified as G3-LCNEC. The median OS was 41 months for G3-WDNET but 17 months for G3-LCNEC(P=0.34). Short survival was observed in 25% of G3-WDNET but 62.5% of G3-LCNEC patients (P=0.049). G3 ENETS GEP and thoracic neuroendocrine neoplasms (NEN) could constitute a heterogeneous subgroup of NEN as regards diagnosis, prognosis, and treatment. If confirmed, future classifications may consider splitting them into two groups according to their morphological differentiation.
Department of Nuclear Medicine and Endocrine Oncology, Villejuif, France.