The poor prognosis factors in G2 neuroendocrine tumor

The G2 neuroendocrine tumors (NET) or well-differentiated neuroendocrine carcinomas (2010 WHO Classification of Tumours of the Digestive System) embrace different types of evolution despite the fact that they actually are included in the same group of prognosis based on mitotic count and the Ki-67 proliferation index.

We studied the pathological and clinical aspects in patients with G2 NET.

This is a retrospective pilot observational study in patients admitted between January 2008 and January 2013 in "Constantin I. Parhon" National Institute of Endocrinology, Bucharest, Romania. They were evaluated based on the pathological report, imagistic scan, and neuroendocrine markers.

Nine patients (female/male ratio: 5/4) with G2 NET were included (mean age at diagnosis 54.11 years). Surgery was performed in 66.66% of cases. 44.44% of tumors had unknown origin. 22.22% of patients had negative immunostain for chromogranin A. Synaptophysin was positive in all cases. Neuronal specific enolase (NSE) was performed in 44.44% of cases and it was positive in all these situations. 88.88% of patients had high neuroendocrine markers. Multiple tumors were found in two cases (follicular thyroid adenoma, and a carcinoma of the port vein, respective bilaterally pheochromocytomas). The youngest patient (39-year-old) had atypical onset with bilateral adrenal tumors (positive for CHROMO, EMA, CK-19, CK-20, negative for SOMATO, CK-7, S-100, glucagon, CD57, and a Ki-67 of 15%). Death was registered in two cases, both with bone metastases.

Some poor prognosis factors may be taken into account as lack of CHROMO immunostain, young age at diagnosis, genetic background, and lack of therapy options as surgery. Larger databases will provide more information.

It is possible that the G2 NET group of tumors actually includes some different subtypes or in fact, a late diagnosis of the tumor might be associated with a poor diagnosis.