Francesca Spada

The Clinicopathologic Heterogeneity of Grade 3 Gastroenteropancreatic Neuroendocrine Neoplasms: Morphological Differentiation and Proliferation Identify Different Prognostic Categories

Background/Aims: Gastroenteropancreatic (GEP) neuroendocrine carcinomas (NECs) are defined as neuroendocrine neoplasms (NENs) with a Ki-67 index >20% according to the 2010 WHO classification. Some reports suggest that this category is heterogeneous. We retrospectively studied a series of 136 patients affected by grade 3 GEP-NECs with the aim to clarify the prognostic role of tumor morphological differentiation, proliferation, defect in mismatch repair proteins (MMRd), CD117 expression, and site of origin. The primary endpoint was the correlation between these parameters and the overall survival (OS). Methods: Univariate and multivariable Cox proportional hazards regression analyses were used to assess the prognostic significance of various clinical and histopathologic features. Results: With a median follow-up of 81 months, the median OS was 12.9 months. At multivariate analysis, morphological differentiation, Ki-67 index, MMRd, stage, and CD117 expression were independent prognostic markers in NECs. Three different prognostic categories of NECs were identified according to the degree of morphologic differentiation (well vs. poorly differentiated) and Ki-67 index (<55% vs. ≥55%). On this basis, median OS was 43.6 months in well-differentiated neoplasms with a Ki-67 index 20-55% (named type A), 24.5 months in poorly differentiated neoplasms with a Ki-67 index 20-55% (type B), and 5.3 months (p < 0.0001) in poorly differentiated neoplasms with a Ki-67 index ≥55% (type C). Conclusions: The present study suggests that GEP-NECs represent a heterogeneous group of neoplasms which can be better classified in different prognostic categories using both tumor morphology and Ki-67 index.

Everolimus in combination with octreotide long-acting repeatable in a first-line setting for patients with neuroendocrine tumors: an ITMO group study.

Preclinical and clinical studies suggest synergistic activity between somatostatin analogues and mammalian target of rapamycin inhibitors. The activity and safety of everolimus was assessed in combination with octreotide long‐acting repeatable (LAR) in patients with neuroendocrine tumors (NETs) of gastroenteropancreatic and lung origin.

Chemotherapy in gastroenteropancreatic (GEP) neuroendocrine carcinomas (NEC): A critical view

Neuroendocrine tumors (NET) are classified according to the Ki67 in low-intermediate grade (Ki67<20%) and high grade (Ki67>20%). The NET of the latter group are also known as neuroendocrine carcinoma (NEC), and their prognosis is dismail. While in the former group biotherapy and radionuclide therapy can be proposed, chemotherapy represents the only treatment usually proposed for NEC. Cisplatin/etoposide combination is usually chosen based on the rationale that NEC are clinically similar to small cell lung cancer. However, evidence for cisplatin/etoposide in NEC is poor and controversial, and different schedules and response rate have been published so far. These aspects, combined with the heterogeneous characteristics of NEC, prompt us to have some doubt in considering cisplatin/etoposide as the gold standard. Some evidence exists that carboplatin can be used instead of cisplatin and irinotecan instead of etoposide without reducing efficacy. Furthermore other drugs, as gemcitabine, oxaliplatin or temozolomide can be evaluated in NEC with non-neuroendocrine component or in mixed adenoneuroendocrine carcinomas. NEC are a category of NET that should be deeply studied to verify if the response to cisplatin/etoposide is homogeneous related to the different Ki67, different morphology and/or different primary site.

Resection of the primary pancreatic neuroendocrine tumor in patients with unresectable liver metastases: possible indications for a multimodal approach.

BACKGROUND Pancreatic neuroendocrine tumors (PNETs) present in more than 50% of cases with liver metastases as the only systemic localization. Liver metastases are unresectable in 80% of cases at diagnosis. In the context of a metastatic disease, the benefit of primary tumor removal in terms of survival is controversial. METHODS A single-center series of patients with PNETs presenting with synchronous unresectable hepatic metastases and treated within a framework of a multidisciplinary team was analyzed retrospectively to assess the prognostic factors and the potential benefit of primary tumor resection on long-term survival. RESULTS At the time of diagnosis, 12 of 43 patients (28%) underwent primary tumor resection. After a median follow-up of 5 years (range, 0.6-14 years), 22 disease-related deaths were observed. The corresponding 5-year survival and median disease-specific duration of survival were 58% and 77 months, respectively. In the operated and nonoperated patients the 5-year disease-specific survival was 82% and 50%, respectively (P = .027). At multivariate analysis, patients with primary tumor removed had an improved survival compared with patients who did not (hazard ratio 0.18; 95% CI 0.05-0.66; P = .010). Other important factors associated with improved survival at multivariate analysis were lesser age, lesser Ki-67 index, and 25% less liver tumor burden. CONCLUSION In the present series of patients with PNETs and unresectable liver metastases, resection of the primary tumor was associated with an improved survival. This observation suggests that resection of the primary tumor should be part of a global therapeutic strategy and its indication and timing should be discussed within a multidisciplinary team.

Temozolomide in Advanced Neuroendocrine Neoplasms: Pharmacological and Clinical Aspects

Alkylating agents, such as streptozocin and dacarbazine, have been reported as active in neuroendocrine neoplasms (NENs). Temozolomide (TMZ) is an oral, potentially less toxic derivative of dacarbazine, which has shown activity both as a single agent and in combination with other drugs. Nevertheless, its role in NENs has not been well defined. Several retrospective and prospective phase I-II studies have been published describing its use in a variety of NENs. In a retrospective series, the combination of capecitabine and TMZ was reported to be associated with a particularly high tumour response in pancreatic NENs as a first-line treatment. Although in NENs, determination of the O6-methylguanine-DNA methyltransferase (MGMT) status has been suggested as a predictive biomarker of response, its role still remains investigational, awaiting validation along with the establishment of the optimal detection method. Metronomic schedules have been reported to potentially overcome MGMT-related drug resistance. Toxicity is manageable if well monitored. We reviewed the literature regarding pharmacological and clinical aspects of TMZ, focusing on specific settings of NENs, different schedules, toxicity and safety profiles, and potential predictive biomarkers of response.

Neuroendocrine tumour arising inside a retro-rectal tailgut cyst: report of two cases and a review of the literature

Tailgut cysts (or retro-rectal cyst-hamartomas (RCHs)) are developmental abnormalities consisting of multiloculated cysts lined by squamous, transitional or glandular epithelium which, albeit rarely, may give rise to malignant transformations. Carcinoid tumours arising in the presacral region are extremely rare and usually benign, and only a few are described in the literature. Case 1: A 63-year-old female diagnosed as having bilateral ovarian cysts underwent surgery to remove a right adnexial mass that was histopathologically diagnosed as a well-differentiated carcinoid tumour. She is currently disease free after 18 months of follow-up. Case 2: A 41-year-old-female diagnosed with hepatic metastases and a solid pelvic mass arising from a moderately differentiated neuroendocrine carcinoma is currently alive with disease after having undergone surgical removal of the mass and several medical treatments. We here describe two different clinical histories of well- and moderately differentiated neuroendocrine tumours (NETs) arising from tailgut cysts in the prerectal space together with a review of the relevant literature.

Everolimus in pancreatic neuroendocrine carcinomas G3

Objective The aim of this study was to investigate everolimus efficacy in well-moderately differentiated pancreatic NEC (pNEC) G3. Methods This was a retrospective analysis of patients with pNEC G3 and Ki67 20% to 55% treated with everolimus. Results Fifteen patients with median Ki67 30% and Eastern Cooperative Oncology Group performance status 0 to 1 were evaluated. Of these, 4 patients received everolimus as first-line treatment, whereas 11 had been pretreated with chemotherapy or peptide receptor radionuclide therapy. Median progression-free survival was 6 months, and median overall survival was 28 months. Eleven patients achieved disease stabilization (DS) at 3 month follow-up. Six patients (40%) maintained DS for at least 12 months. Three of 4 patients who received everolimus as first-line therapy had sustained DS (progression-free survival, 12, 17, and 22 months). The safety profile was consistent with that previously reported, with adverse events occurring in 9 patients (66.7%). Conclusions This study suggests that everolimus is active in pNEC G3 with well-moderately differentiated morphology and Ki67 less than 55%, in which more toxic systemic chemotherapy is, to date, the only available treatment.

Dual inhibition of mTOR pathway and VEGF signalling in neuroendocrine neoplasms: from bench to bedside.

After years of limited progress in the treatment of neuroendocrine neoplasms (NENs), an increasing number of therapeutic targets have recently emerged as potential tools to improve disease outcome. The mammalian target of rapamycin (mTOR) pathway and vascular endothelial growth factor (VEGF) signalling are implicated in the regulation of cell growth, proliferation, neo-angiogenesis and tumour cell spread. Their combined blockade, in a simultaneous or sequential strategy, represents an intriguing biological rationale to overcome the onset of resistance mechanisms. However, is becoming increasingly imperative to find the optimal sequential strategy according to the best toxicity profile, and also to identify predictive biomarkers. We will provide an overview of the pre-clinical and clinical data relating to mTOR pathway/VEGF signalling as a potential targets of treatment in NENs.

Oxaliplatin-Based Chemotherapy in Advanced Neuroendocrine Tumors: Clinical Outcomes and Preliminary Correlation with Biological Factors

Purpose: The role of chemotherapy in low-/intermediate-grade neuroendocrine tumors (NETs) is still debated. We present the results of an Italian multicenter retrospective study evaluating activity and toxicity of oxaliplatin-based chemotherapy in patients with advanced NETs. Methods: Clinical records from 5 referral centers were reviewed. Disease control rate (DCR) corresponding to PR + SD (partial response + stable disease) at 6 months, progression-free survival (PFS), overall survival (OS) and toxicity were calculated. Ki67 labeling index, grade of differentiation and excision- repair-cross-complementing group 1 (ERCC-1) were analyzed in tissue tumor samples. Results: Seventy-eight patients entered the study. Primary sites were: pancreas in 46, gastrointestinal in 24, lung in 19 and unknown in 10% of patients. The vast majority were G2 (2010 WHO classification). Eighty-six percent of the patients were metastatic, and 87% were pretreated and progressive to previous therapies. Sixty-five percent of the patients received capecitabine/oxaliplatin (CAPOX), 6% gemcitabine/oxaliplatin (GEMOX), and 29% leucovorin/fluorouracil/oxaliplatin (FOLFOX-6). PR occurred in 26% of the patients, half of them with pancreatic NETs, and SD in 54%. With a median follow-up of 21 months, the median PFS and OS were 8 and 32 months with 70 and 45 events, respectively. The most frequent G3 toxicities were neurological and gastrointestinal. ERCC-1 immunohistochemical overexpression was positive in 4/28 evaluated samples, with no significant correlation with clinical outcome. Conclusion: This analysis suggests that oxaliplatin-based chemotherapy can be active with a manageable safety profile in advanced NETs irrespective of the primary sites and tumor grade. The 80% DCR and 8-month PFS could justify a prospective study in NETs with intermediate biological characteristics, especially with pancreatic primary tumors.

RAF signaling in neuroendocrine neoplasms: from bench to bedside.

Neuroendocrine neoplasms are a low-incidence and heterogeneous group of malignancies. In the advanced stage, several therapeutic options can be discussed, including molecular-targeted agents, but biological predicting factors are lacking. A number of molecular targets have been studied over the last decade leading to several phase II studies; however, very few agents progressed to phase III clinical trials. The RAF family of proteins belongs to the mitogen-activated protein kinase (MAPK) pathway, that has a role in several types of cancers, particularly related to BRAF mutations. Indeed BRAF inhibitors have been reported as being effective, mainly in melanoma. However, in neuroendocrine neoplasms BRAF mutations are extremely rare and RAF-1 activation has been reported to inhibit tumor growth in a pre-clinical setting. Therefore, in this field, RAF-1 activators rather than BRAF inhibitors should be clinically investigated. This article reviews the basic science as well as clinical data of RAF signaling in advanced neuroendocrine neoplasms with special emphasis on the potential role of both RAF activators and inhibitors.