Data on gastroenteropancreatic neuroendocrine neoplasms (NEN) G3 (well-differentiated neuroendocrine tumors (NET G3) and neuroendocrine carcinoma (NEC)) are limited. We retrospectively study patients with NET G3 and NEC from eight European centers. Data examined included clinical and pathological characteristics at diagnosis, therapies and outcomes. Two hundred and four patients were analyzed (37 NET G3 and 167 NEC). Median age was 64 (21-89) years. Tumor origin included pancreas (32%) and colon-rectum (27%). The primary tumor was resected in 82 (40%) patients. Metastatic disease was evident at diagnosis in 88% (liver metastases: 67%). Median Ki-67 index was 70% (30% in NET G3 and 80% in NEC; P!0.001). Median overall survival (OS) for all patients was 23 (95% CI: 18-28) months and significantly higher in NET G3 (99 vs 17 months in NEC; HRZ8.3; P!0.001). Platinum-etoposide first line chemotherapy was administered in 113 (68%) NEC and 12 (32%) NET G3 patients. Disease control rate and progression free survival (PFS) were significantly higher in NEC compared to NET G3 (P!0.05), whereas OS was significantly longer in NET G3 (PZ0.003). Second-and third-line therapies (mainly FOLFIRI and FOLFOX) were given in 79 and 39 of NEC patients; median PFS and OS were 3.0 and 7.6 months respectively after second-line and 2.5 and 6.2 months after third-line chemotherapy. In conclusion, NET G3 and NEC are characterized by significant differences in Ki-67 index and outcomes. While platinum-based chemotherapy is effective in NEC, it seems to have limited value in NET G3.

The new WHO classification of gastroenteropancreatic (GEP) neuroendocrine tumors (NET) implies that G3 neoplasms with mitotic index O20 and/or Ki67 index O20% 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 O20 and/or Ki67 O20% 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 (PZ0.34). Short survival was observed in 25% of G3-WDNET but 62.5% of G3-LCNEC patients (PZ0.049). 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.

Cyclophosphamide-dacarbazine-vincristine regimen is recommended for the treatment of malignant pheochromocytoma and paraganglioma (MPP); however, dacarbazine is the only recognized active drug in neuroendocrine tumours. We investigated the therapeutic benefit of temozolomide (TMZ), an oral alternative to dacarbazine, in patients with MPP. This is a retrospective study of consecutive patients with documented progressive MPP. We examined the correlation between Succinate dehydrogenase B (SDHB) mutation and O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation and MGMT expression in the French nation-wide independent cohort of 190 pheochromocytomas or paragangliomas (PP). Progression-free survival (PFS) according to RECIST 1.1 and PERCIST 1.0 criteria was the primary end point. Fifteen consecutive patients with MPP were enrolled; ten (67%) carried a mutation in SDHB. The mean dose intensity of TMZ was 172 mg/m 2 /d for 5 days every 28 days. Median PFS was 13.3 months after a median follow-up of 35 months. There were five partial responses (33%), seven stable (47%) and three progressive diseases (20%). Grade 3 toxicities were lymphopenia in two patients and hypertension in one. Partial responses were observed only in patients with mutation in SDHB. MGMT immunohistochemistry was negative in tumour samples from four patients who responded to treatment. SDHB germline mutation was associated with hypermethylation of the MGMT promoter and low expression of MGMT in 190 samples of the French nation-wide independent cohort. This study demonstrates that TMZ is an effective antitumour agent in patients with SDHB-related MPP. The silencing of MGMT expression as a consequence of MGMT promoter hypermethylation in SDHB-mutated tumours may explain this finding.Key words: malignant pheochromocytoma, paraganglioma, O(6)-methylguanine-DNA methyltransferase (MGMT), succinate dehydrogenase B (SDHB), temozolomide Additional Supporting Information may be found in the online version of this article. Malignant pheochromocytoma and paraganglioma (PP) are frequently associated with mutations in succinate dehydrogenase B (SDHB). We found a correlation between mutations in SDHB and hypermethylation of the promoter of O6-methylguanine-DNA methyltransferase (MGMT) in tumour samples from a French cohort of 190 patients with PP. Temozolomide yielded a clinical benefit in 67% of 15 patients treated for progressive malignant PP. The expression of MGMT was deficient in tumour samples from four of the five patients who responded to treatment. These results suggest that a personalized therapeutic approach may be applicable to this rare cancer.

Sunitinib is associated with tumor size reduction, decreased [(18)F]FDG-PET/CT uptake, disease stabilization, and hypertension improvement in some patients with progressive metastatic PHEO/PGL. Prospective multi-institutional clinical trials are needed to determine the true benefits of sunitinib.

There is no standard for second-line chemotherapy in poorly differentiated grade 3 neuroendocrine carcinoma (G3-NEC) patients. We analyzed the antitumor efficacy of 5-fluorouracil and oxaliplatin (FOLFOX) chemotherapy in this population. A single-center retrospective analysis of consecutive G3-NEC patients treated with FOLFOX chemotherapy after failure of a cisplatinum-based regimen between December 2003 and June 2012 was performed. Progression-free survival (PFS), overall survival (OS), response rate, and safety were assessed according to RECIST 1.1 and NCI.CTC v4 criteria. Twenty consecutive patients were included (seven males and 13 females; median age 55; range 23-87 years) with a performance status of 0-1 in 75% of them. Primary location was gastroenteropancreatic in 12, thoracic in four, other in two, and unknown in two patients. There were 12 (65%) large-cell and 7 (30%) small-cell G3-NEC tumors, and 1 (5%) unknown. All patients had distant metastases. Twelve (60%) patients received FOLFOX as second-line treatment and 8 (40%) as third-line treatment or later and the median number of administered cycles was 6 (range 3-14). The median follow-up was 19 months. Median PFS was 4.5 months. Among the 17 evaluable patients, five partial responses (29%), six stable diseases (35%), and six progressive diseases (35%) were observed. Median OS was 9.9 months. Main Grade 3-4 toxicities were neutropenia (35%), thrombopenia (20%), nausea/vomiting (10%), anemia (10%), and elevated liver transaminases (10%). Our results indicate that the FOLFOX regimen could be considered as a second-line option in poorly differentiated G3-NEC patients after cisplatinum-based first-line treatment but warrant further confirmation in future larger prospective studies. Key Words" neuroendocrine carcinoma