Is the new WHO classification of neuroendocrine tumours useful for selecting an appropriate treatment?

From biology to clinical practice: antiproliferative effects of somatostatin analogs in neuroendocrine neoplasms

Somatostatin analogs (SSA), specifically octreotide and lanreotide, have demonstrated antiproliferative effects in patients with neuroendocrine tumors (NET), a group of rare malignancies of diverse origin and presentation. A prominent feature of NET cells is the expression of G protein-coupled receptors called somatostatin receptors (SSTR). Although these SSTR are not uniformly present in NET, they can be instrumental in the diagnosis and treatment of NET. Apart from their application in nuclear imaging and radionuclide therapy, SSA have proven invaluable in the treatment of hormonal syndromes associated with certain NET (antisecretory effects of SSA), but it took more than two decades to convincingly demonstrate the antiproliferative effects of SSA in metastatic NET with the two pivotal studies PROMID and CLARINET. The current review summarizes three decades of SSA treatment and provides an overview of the clinical trial landscape for SSA monotherapy and combination therapy, including clinical implications and quality of life aspects, as well as ongoing fields of research.

The Ki-67 antigen in the new 2021 World Health Organization classification of lung neuroendocrine neoplasms

Prof. Rosai's work has permeated the surgical pathology in many fields, including the 2017 World Health Organization classification on tumors of endocrine organs and pulmonary neuroendocrine cell pathology, with stimulating contributions which have also anticipated the subsequent evolution of knowledge. Among the many studies authored by Prof. Rosai, we would like to recall one of which whose topic has been encased in the new 2021 World Health Organization classification on lung tumors. This is an eminently practical paper dealing with the use of the proliferation antigen Ki-67 in lung neuroendocrine neoplasms. While these neoplasms are primarily ranked upon histologic features and Ki-67 labeling index does not play any role in classification, diagnostic dilemmas may however arise in severely crushed biopsy or cytology samples where this marker proves helpful to avoid misdiagnoses of carcinoids as small cell carcinoma. Another application of Ki-67 labeling index endorsed by the 2021 World Health Organization classification regards, alongside mitotic count, the emerging recognition of lung atypical carcinoids with increased mitotic or proliferation rates, whose biological boundaries straddle a subset of large cell neuroendocrine carcinoma.

This article focuses on these two practical applications of the proliferation marker Ki-67 in keeping with the 2021 World Health Organization classification, which provides standards for taxonomy, diagnosis and clinical decision making in lung neuroendocrine neoplasm patients.

Colorectal neuroendocrine tumors: A case series

INTRODUCTION

Neuroendocrine tumors (NET) of the colon and sigmoid colon are uncommon compared to colorectal adenocarcinoma. Few reports have been made of NET of the colon and sigmoid colon that presents with peritonitis and large bowel obstruction.

CASE PRESENTATION

Here, we report two cases of NET of the colon and sigmoid colon, which were diagnosed and treated at our institution. In our first case, a 66-year-old man with a history of abdominal distension was diagnosed with NET via histopathology of the sigmoid colon. The second case involved a 45-year-old woman with the chief complaints of abdominal distention and inability to defecate; specimen histopathology of the descending colon showed neuroendocrine carcinoma features. Clinical outcome was very poor in our patients: eight months after the resection, the second patient demonstrated a sign of metastasis on the liver.

CONCLUSION

An uncommon case of colon and sigmoid colon carcinoma with neuroendocrine and diagnostic difficulties precludes an exact description of the initial diagnostic criteria and management. Thus, our case series offers an overview of initial symptoms, radiological and histopathological features for early diagnosis, and proper management of NET.

Systematic literature review of the antitumor effect of octreotide in neuroendocrine tumors

AIM

To provide a comprehensive examination of the existing evidence of the antitumor effect of long-acting octreotide in neuroendocrine tumors (NETs).

METHODS

A systematic literature review of clinical trials and observational studies was conducted in PubMed, EMBASE, and Cochrane through January 18, 2017. Conference abstracts for 2015 and 2016 from 5 scientific meetings were also searched.

RESULTS

Of 41 articles/abstracts identified, 13 unique studies compared octreotide with active or no treatment. Two of the 13 studies were clinical trials; the remaining were observational studies. The phase 3 Placebo-Controlled, Double-Blind, Prospective, Randomized Study of the Effect of Octreotide long-acting repeatable (LAR) in the Control of Tumor Growth in Patients with Metastatic Neuroendocrine Midgut Tumors clinical trial showed that long-acting octreotide significantly prolonged time to tumor progression compared with placebo in patients with functionally active and inactive metastatic midgut NETs; no statistically significant difference in overall survival (OS) was observed, possibly due to the crossover of placebo patients to octreotide. Retrospective observational studies found that long-acting octreotide use was associated with significantly longer OS than no octreotide use for patients with distant metastases although not for those with local/regional disease.

CONCLUSION

The clinical trial and observational studies with informative evidence support long-acting octreotide’s antitumor effect on time to tumor progression and OS. This review showed the rarity of existing studies assessing octreotide’s antitumor effect and recommends that future research is warranted.

Neuroendocrine tumors of unknown primary site: Gold dust or misdiagnosed neoplasms?

Aims and background

Neuroendocrine tumors of an unknown primary site are rarer than other neuroendocrine tumors (0.6–2% of all neuroendocrine tumors) and have a poor prognosis. The aim of the study was to review the cases of unknown primary site neuroendocrine tumors encountered at the Istituto Nazionale Tumori of Milan between 1984 and 2008 in order to verify their incidence and evaluate their characteristics and prognosis.

Methods and study design

During the study period, 750 neuroendocrine tumor patients attended our Institute, 82 of whom (10.9%) were diagnosed as having neuroendocrine tumors of an unknown primary site. The data from their medical records were analyzed descriptively, and survival probabilities were calculated using the Kaplan-Meier method and the logrank test, considering patient, tumor and treatment-related characteristics.

Results

The 82 patients with neuroendocrine tumors of an unknown primary site (34 males) had a median age of 60 years; 57 (69.5%) had histologically well-differentiated tumors, 3 (3.7%) poorly differentiated tumors, and 22 (26.8%) had tumors that could not be classified. Of the 52 patients (62.2%) who underwent Octreoscan(®) (Bykgulden Italia SpA), 40 (78.4%) showed a pathological uptake and 11 (21.6%) were negative. Thirty-one patients (37.8%) underwent metastatic site surgery, which was radical in 11 cases (35.4%). Forty-eight patients (58.5%) received somatostatin analogues, and 41 (50.0%) underwent chemotherapy. At the end of the study period, 59 patients (72.0%) had died, 31 (53.0%) because of disease progression, and 23 (28.0%) were still alive.

Conclusions

Neuroendocrine tumors of an unknown primary site are difficult to identify but their incidence is higher than previously reported, and the prognosis remains unfavorable.

Long-acting somatostatin analogues in the treatment of unresectable/metastatic neuroendocrine tumors

Neuroendocrine tumors (NETs) are a relatively rare and heterogeneous group of neoplasms with an annual incidence of ~35 cases per 100,000 people in the United States. The updated World Health Organization (WHO) classification system of gastroenteropancreatic (GEP)-NETs categorizes these tumors according to site of origin, clinical syndrome, and degree of differentiation. Well-differentiated NETs arising from the gastrointestinal tract or lungs (formerly known as carcinoid tumors) are often indolent and slow-growing. In contrast, poorly differentiated neuroendocrine carcinomas (NECs) are aggressive and have a poor prognosis. Due to their insidious onset, most NETs are diagnosed at an advanced stage and a curative approach is not possible. In these patients, medical therapy is limited to disease control, including relief of symptoms that arise from overproduction of peptide hormones by the tumors. Somatostatin analogues (SSAs) have remained the mainstay of symptoms control. In addition to symptoms control, clinical data also support an anti-proliferative effect of SSAs in patients with well- to moderately differentiated NETs. Long-acting SSAs have greatly facilitated their use. This review will focus on two long-acting SSAs, octreotide LAR and lanreotide, and their use in the clinical setting. Information necessary to assess their relative merits is summarized. We conclude these two therapies are interchangeable making value a very important consideration in their use.

Pancreatic Cytopathology

Pancreatic cytopathology, particularly through the use of endoscopic ultrasound-guided fine-needle aspiration (FNA), has excellent specificity and sensitivity for the diagnosis of pancreatic lesions. Such diagnoses can help guide preoperative management of patients, provide prognostic information, and confirm diagnoses in patients who are not surgical candidates. Furthermore, FNA can be used to obtain cyst fluid for ancillary tests that can improve the diagnosis of cystic lesions. In this article, we describe the cytomorphological features and differential diagnoses of the most commonly encountered pancreatic lesions on FNA.

Cardiothoracic manifestations of neuroendocrine tumours

Cardiothoracic neuroendocrine tumour (NET) manifestations encompass a vast disease spectrum. Pulmonary neuroendocrine tumours represent a range of tumour grade and differentiation characteristics from pre-malignant diffuse neuroendocrine cell hyperplasia, well-differentiated, low-grade carcinoid tumours with excellent outcomes, through to high-grade small-cell lung carcinoma and large-cell neuroendocrine carcinoma with poor prognoses. Rarer thymic NETs represent a similarly wide neoplastic spectrum. Cardiac carcinoid is a paraneoplastic manifestation of the carcinoid syndrome and often the cause of mortality in NETs with hepatic metastases. Cardiothoracic NET manifestations are reviewed herein from a radiologists' perspective, discussing the diverse clinical presentations, spectrum of neoplastic and paraneoplastic manifestations, imaging features and treatment options.

Neuroendocrine tumours - Medical therapy: Biological

Somatostatin analogues (SSA) are well established antisecretory drugs that have been used as first line treatment for symptomatic control in hormonally active neuroendocrine tumours (NET) for three decades. Both available depot formulations of SSA, long-acting repeatable (LAR) octreotide and lanreotide autogel, seem similarly effective and well tolerated, although comparative trials in NET have not been performed. The importance of SSA as antiproliferative treatment has been increasingly recognized during recent years. Two placebo-controlled trials demonstrated significant prolongation of progression free survival under SSA treatment. However, objective response as assessed by imaging is rare. Interferon-α (IFNα) also has antisecretory and antiproliferative efficacy in NET. Due to the less favourable toxicity profile it mainly has a role as add-on option in the refractory setting, especially in carcinoid syndrome patients. Further studies are needed to evaluate the antiproliferative efficacy of the multiligand SSA pasireotide and the role of pegylated IFNα.

The usefulness of endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic neuroendocrine tumors based on the World Health Organization classification

BACKGROUND

We assessed the controversial topic of using 22-gauge needles in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for the diagnosis and evaluation of Ki67 labeling indices (Ki67LI) of pancreatic neuroendocrine tumors (pNET).

METHODS

Thirty-eight patients with pNET who underwent EUS-FNA between January 1, 2008 and December 31, 2012 were enrolled in this study. When available, the Ki67LI and WHO classifications obtained by EUS-FNA and surgical resection were compared.

RESULTS

EUS-FNA with a 22-gauge needle acquired sufficient histological sample to correctly diagnose pNET in 35 cases (92.1%). Both EUS-FNA and surgical histological specimens were available for 19 cases, and grading classes of the 2 procedures were consistent in 17 cases (89.5%) according to the WHO classification based on the Ki67LI. Tumor size was associated with a difference in the Ki67LI between the 2 procedures, although the Ki67LI was almost completely consistent for tumors less than 18 mm in size.

CONCLUSIONS

EUS-FNA with a 22-gauge needle is a safe and highly accurate technique for the diagnosis of pNET. There was a clear correlation between the Ki67LI of histological specimens acquired by EUS-FNA and surgery. EUS-FNA with a 22-gauge needle is useful to predict the WHO classification of pNET.

Lanreotide in metastatic enteropancreatic neuroendocrine tumors

BACKGROUND

Somatostatin analogues are commonly used to treat symptoms associated with hormone hypersecretion in neuroendocrine tumors; however, data on their antitumor effects are limited.

METHODS

We conducted a randomized, double-blind, placebo-controlled, multinational study of the somatostatin analogue lanreotide in patients with advanced, well-differentiated or moderately differentiated, nonfunctioning, somatostatin receptor-positive neuroendocrine tumors of grade 1 or 2 (a tumor proliferation index [on staining for the Ki-67 antigen] of <10%) and documented disease-progression status. The tumors originated in the pancreas, midgut, or hindgut or were of unknown origin. Patients were randomly assigned to receive an extended-release aqueous-gel formulation of lanreotide (Autogel [known in the United States as Depot], Ipsen) at a dose of 120 mg (101 patients) or placebo (103 patients) once every 28 days for 96 weeks. The primary end point was progression-free survival, defined as the time to disease progression (according to the Response Evaluation Criteria in Solid Tumors, version 1.0) or death. Secondary end points included overall survival, quality of life (assessed with the European Organization for Research and Treatment of Cancer questionnaires QLQ-C30 and QLQ-GI.NET21), and safety.

RESULTS

Most patients (96%) had no tumor progression in the 3 to 6 months before randomization, and 33% had hepatic tumor volumes greater than 25%. Lanreotide, as compared with placebo, was associated with significantly prolonged progression-free survival (median not reached vs. median of 18.0 months, P<0.001 by the stratified log-rank test; hazard ratio for progression or death, 0.47; 95% confidence interval [CI], 0.30 to 0.73). The estimated rates of progression-free survival at 24 months were 65.1% (95% CI, 54.0 to 74.1) in the lanreotide group and 33.0% (95% CI, 23.0 to 43.3) in the placebo group. The therapeutic effect in predefined subgroups was generally consistent with that in the overall population, with the exception of small subgroups in which confidence intervals were wide. There were no significant between-group differences in quality of life or overall survival. The most common treatment-related adverse event was diarrhea (in 26% of the patients in the lanreotide group and 9% of those in the placebo group).

CONCLUSIONS

Lanreotide was associated with significantly prolonged progression-free survival among patients with metastatic enteropancreatic neuroendocrine tumors of grade 1 or 2 (Ki-67 <10%). (Funded by Ipsen; CLARINET ClinicalTrials.gov number, NCT00353496; EudraCT 2005-004904-35.).

Somatostatin analogs: does pharmacology impact antitumor efficacy?

Somatostatin is an endogenous inhibitor of secretion and cell proliferation. These features render somatostatin a logical candidate for the management of neuroendocrine tumors that express somatostatin receptors. Synthetic somatostatin analogs (SSAs) have longer half-lives than somatostatin, but have similar activities, and are used for the treatment of these types of disorders. Interest has focused on novel multireceptor analogs with broader affinity to several of the five somatostatin receptors, thereby presenting putatively higher antitumor activities. Recent evidence indicates that SSAs cannot be considered mimics of native somatostatin in regulating signaling pathways downstream of receptors. Here we review this knowledge, discuss the concept of biased agonism, and highlight what considerations need to be taken into account for the optimal clinical use of SSAs.

Octreotide - A Review of its Use in Treating Neuroendocrine Tumours

Neuroendocrine tumours (NETs) are a heterogeneous group of neoplasms whose incidence has dramatically increased in recent years. Octreotide is a somatostatin analogue used in the treatment of NETs, and its use in clinical trials has been associated with substantially increased survival. Although traditionally used for the relief of symptoms that result from release of peptides and neuroamines, there has been a growing body of evidence that suggest octreotide has antiproliferative effects. A phase III clinical study has demonstrated that the long-acting formulation (LAR), octreotide LAR, lengthens time to tumour progression in patients with well-differentiated metastatic midgut NETs, and that octreotide LAR is a treatment option for patients with metastatic midgut NETs, regardless of functional status. Furthermore, octreotide LAR has demonstrated clinical efficacy in different types of NETs. These data, along with emerging data on somatostatin analogs, may change the way doctors approach this patient population and reinforce the use of these drugs as a treatment option for patients with non-functioning tumours.

KIF5B-RET fusions in Chinese patients with non-small cell lung cancer

BACKGROUND

It has been established that "ret proto-oncogene" (RET) fusions are oncogenic drivers in non-small cell lung cancer (NSCLC). The prevalence and clinicopathologic characteristics of RET fusions in Chinese patients with NSCLC remain unclear. The objective of the current study was to determine the prevalence and clinicopathologic characteristics of KIF5B-RET fusions (fusions of the RET and kinesin family member 5B [KIF5B] genes) in Chinese patients with NSCLC.

METHODS

The authors screened for KIF5B-RET fusions in 392 patients with NSCLC using multiplex real-time polymerase chain reaction assay and validated all positive samples using direct sequencing. The relations between KIF5B-RET fusions and clinicopathologic characteristics were analyzed.

RESULTS

In total, 6 patients (1.5%) were identified who harbored KIF5B-RET fusions. Of these, 4 had adenocarcinoma, 1 had a malignant neuroendocrine tumor, and 1 had squamous cell carcinoma. All patients who were positive for a KIF5B-RET fusion were never-smokers. There was no statistically significant difference in age, sex, smoking status, pathologic stage, or histologic type between patients with and without KIF5B-RET fusions. Patients without KIF5B-RET fusions had a better prognosis than those with KIF5B-RET fusions (median survival, 52.6 months vs 21.0 months; P = .06), with a hazard ratio of 2.398 (95% confidence interval, 0.982-5.856; P = .055) on multivariate analysis. Disease stage (hazard ratio, 2.879) and younger age (<65 years; hazard ratio, 1.485) were identified as independent prognostic factors for better survival.

CONCLUSIONS

KIF5B-RET fusions were quite rare, with a prevalence of approximately 1.5% in Chinese patients with NSCLC, and they were a little more common in patients with adenocarcinoma than in those with squamous carcinoma (1.73% vs 0.84%). In addition, KIF5B-RET fusions also existed in patients with low-grade malignant neuroendocrine tumors.

Poorly differentiated neuroendocrine carcinoma in a perigastric lymph node from an unknown primary site

Neuroendocrine carcinomas from an unknown primary site are uncommon. The authors report on a case of neuroendocrine carcinoma in a perigastric lymph node (LN) with no primary site. A 52-year-old male patient with early gastric adenocarcinoma underwent treatment by endoscopic submucosal dissection, and, six months later, findings on a computed tomographic scan of the abdomen revealed a LN enlargement measuring 2.0 cm in the perigastric region. The patient underwent subtotal gastrectomy and regional LN dissection under a suggestive preoperative diagnosis of gastric adenocarcinoma with LN metastasis. However, microscopically, no residual tumor was found in the stomach, and the perigastric LN showed poorly differentiated neuroendocrine carcinoma (PDNEC). After an extensive workup, no primary site was identified. The patient also received four cycles of etoposide and cisplatin. Despite its extremely rare incidence, this case suggests that PDNEC of an unknown primary site is limited to a single site, and that resection should be considered in combination with chemotherapy.

Antitumor effects of somatostatin analogs in neuroendocrine tumors

BACKGROUND

For decades, somatostatin analogs (including octreotide and lanreotide) have been indicated for relief of the symptoms of flushing, diarrhea, and wheezing associated with secretory neuroendocrine tumors (NETs). Recently, it has been suggested that somatostatin analogs may provide direct and indirect antitumor effects in secretory and nonsecretory NETs in addition to symptom control in secretory NETs.

METHODS

A systematic review of MEDLINE was conducted to identify studies that investigated the antitumor effects of octreotide or lanreotide for patients with NETs. Additional studies not published in the peer-reviewed literature were identified by searching online abstracts. Results. In all, 17 octreotide trials and 11 lanreotide trials that included antitumor effects were identified. Partial response rates were between 0% and 31%, and stable disease rates were between 15% and 89%. Octreotide was the only somatostatin analog for which results of a phase III, randomized, placebo-controlled clinical trial that investigated antitumor effects were published. After 6 months of treatment in this randomized phase III trial, stable disease was observed in 67% of patients (hazard ratio for time to disease progression: 0.34; 95% confidence interval: 0.20-0.59; p = .000072).

CONCLUSIONS

In addition to symptom control for NETs, the data support an antitumor effect of somatostatin analogs and suggest that they may slow tumor growth. Long-acting repeatable octreotide has been shown to have an antitumor effect in a randomized phase III trial in midgut NETs, whereas results are pending in a corresponding controlled trial with lanreotide for patients with intestinal and pancreatic primary NETs.

Pancreatic incidentalomas

Pancreatic incidentalomas are defined as asymptomatic pancreatic lesions, discovered incidentally by imaging for an unrelated indication. They are being discovered with increasing frequency as the use of high quality cross sectional imaging is becoming more widespread. These lesions cover a wide spectrum of pathology from benign simple cysts through potentially malignant lesions such as intraductal papillary mucinous neoplasia, to frankly malignant adenocarcinoma. In this article we outline the incidence, imaging characteristics and natural history of the various incidental lesions with emphasis to neuroendocrine tumors. A diagnostic approach is also suggested, including the rational use of further imaging, serum biochemistry and the utility of ultrasound guided aspiration of cyst fluid if present. We examine several proposed classification systems and discuss the role of surgery, surveillance and prognosis.

Predictors of response to radio-embolization (TheraSphere®) treatment of neuroendocrine liver metastasis

BACKGROUND

Neuroendocrine tumours (NET) frequently metastasize to the liver. NET liver metastasis has been shown to respond to Yttrium-90 microspheres therapy. The aims of the present study were to define factors that predict the response to radio-embolization in patients with NET liver metastases.

METHODS

From January 2006 until March 2009, all patients with NET liver metastasis that received radio-embolization using TheraSphere® (glass microspheres) were reviewed. The response was determined by a change in the percentage of necrosis (ΔN%) after the first radio-embolization based on the modified RECIST criteria (mRECIST) criteria. The following confounding variables were measured: age, gender, size of the lesions, liver involvement, World Health Organization (WHO) classification, the presence of extra-hepatic metastasis, octereotide treatment and previous operative [surgery and (RFA)] and non-operative treatments (chemo-embolization and bland-embolization).

RESULTS

In all, 25 patients were identified, with a median follow-up of 21.7 months. The median age was 64.6 years, 28% had extra-hepatic metastasis and 56% were WHO stage 2. Post-treatment, the mean ΔN% was 48.4%. Previous surgical therapy was a significant predictor of the response with a response rate of 66.7 ΔN% vs. 31.5 ΔN% (P= 0.02). Bilateral liver disease, a high percentage of liver involvement and large metastatic lesions were inversely related to the degree of tumour response although did not reach statistical significance.

CONCLUSION

Radio-embolization increased the necrosis of NET liver metastasis mainly in patients with less bulky disease. This may imply that surgical therapy before radio-embolization would increase the response rates.

Choice of tumour markers in patients with neuroendocrine tumours is dependent on the histological grade. A marker study of Chromogranin A, Neuron specific enolase, Progastrin-releasing peptide and cytokeratin fragments

BACKGROUND

Chromogranin A (CgA) is the most important tumour marker for well-differentiated neuroendocrine tumours (NET) and neuron specific enolase (NSE) for poorly differentiated neuroendocrine carcinoma (NEC). This study investigated whether the markers progastrin-releasing peptide (proGRP) and cytokeratin fragments (CKfr) CK8, CK18 and CK19 (MonoTotal) can be of additional value to the histological classification and help predict survival in these patients.

METHODS

CgA, NSE, proGRP and CKfr were measured in 242 patients with grade 1 NET (G1NET), 38 with grade 2 NET (G2NET), 42 with large cell NEC (LCNEC), 251 with small cell NEC (SCNEC) and in 282 healthy persons. Results were compared with tumour characteristics and survival by means of Receiver Operating Characteristics (ROC) curves and Cox regression analyses.

RESULTS

The largest area under the ROC curve was for CgA (0.86, 0.91 and 0.90, respectively) when comparing patients with G1NET, G2NET and LCNEC with healthy persons. ProGRP showed the highest sensitivity (73%) at 95% specificity in patients with SCNEC. In a multivariate survival analysis, only CKfr was associated with survival (P<0.0001) for patients with well-differentiated NET (G1NET and G2NET). For patients with poorly differentiated NEC, both CKfr and NSE were associated with survival (P<0.0001 and P=0.003, respectively).

CONCLUSION

Within all histological groups a combination of tumour markers proved to be more informative as diagnostic and prognostic marker than each marker alone. In patients with well-differentiated NET and LCNEC we recommend the use of CgA and CKfr, whilst in patients with SCNEC, proGRP and CKfr are preferred.

Neuroendocrine tumors diagnosed at the Antonio Cardarelli hospital (Naples, Italy) between 2006-2009: a single-institution analysis

Neuroendocrine tumors (NETs) are rare, with an incidence of about 5 per 100,000 inhabitants. As no study on NETs has ever been specifically conducted on the population of Campania, we performed a retrospective analysis of all newly diagnosed NETs at the Antonio Cardarelli hospital between 2006-2009. A search of the registry of the Pathology Department of the Antonio Cardarelli hospital was carried out to retrieve available data on all newly diagnosed NET cases. Two hundred and ninety-nine NET tumors were diagnosed at our Institution from January, 2006 to December, 2009. Globally, 121 patients (40% of the population) had a lung NET, while 92 patients (30% of the population) presented a GEP-NET. The most common primary tumor site varied by sex, with female patients being more likely to have a primary NET in the lung, breast or colon, and male patients being more likely to have a primary tumor in the lung. Also, twenty-three cases of breast NETs were identified, and clinical information regarding therapy and response was available for 22 patients. Our study represents a pioneering effort to provide the medical community in Campania with basic information on a large number of patients with different types of NETs. The Antonio Cardarelli hospital could greatly benefit from cooperation with other hospitals in order to become a highly specialized center for NETs in the region and Southern Italy.

Unusual case of small cell gastric carcinoma: case report and literature review

BACKGROUND

Small cell carcinomas are among the most aggressive, poorly differentiated, and highly malignant of the neuroendocrine tumors (NETs). Of which, small cell gastric carcinoma is a rare small cell neuroendocrine tumor. The purpose of our study was to present this case and perform a comprehensive literature review.

METHODS AND RESULTS

We review a case of small cell gastric carcinoma that is particularly unusual in that it occurred in a woman from the US when the majority of cases of small cell gastric carcinoma have been reported in men from East Asia, and more specifically, from Japan. The diagnosis was made after endoscopy revealed a large ulcerated mass in the gastric cardia of Borrmann type 3. Biopsies revealed multiple small basophilic cells underlying the squamous epithelium of the esophagus and cardiac mucosa, indicating the presence of a tumor at the gastroesophageal junction. Immunostaining established the diagnosis with positive stains for chromogranin, synaptophysin, and CD56. Our patient is being treated with chemotherapy, but many different treatment regimens have been tried for small cell gastric carcinoma with variable success.

CONCLUSIONS

Overall prognosis for small cell gastric carcinoma is dismal. Neuroendocrine tumors in general have variable clinical behaviors and prognosis is dependent on the neuroendocrine tumor type. The adoption of a standardized classification system for neuroendocrine tumors could improve the recognition of infrequently encountered neuroendocrine tumors like small cell gastric carcinoma and will enhance strategies for treatment and thus improve prognosis for patients with these rare and aggressive tumors.

Symptoms and diagnostics of lung neuroendocrine tumors

Pulmonary neuroendocrine tumors comprise 20% of all lung cancers. They are separated into 4 subgroups: typical carcinoid tumor, atypical carcinoid tumor, large-cell neuroendocrine carcinoma, and small-cell lung carcinoma. The major symptoms present in 60% of patients are cough, hemoptysis, and obstructive pneumonia. They may also exhibit hormonally related symptoms e.g. carcinoid syndrome. Small cell lung cancer is the most common subgroup, with rapid progression, aggressive metastatic potential and the worst prognosis. Large cell neuroendocrine carcinoma is rare but also has a poor prognosis. Typical carcinoid may be accompanied with hormone related symptoms and has the best prognosis; atypical one on the contrary may cause lymph node and distant metastases in half of the cases. Elevated plasma levels of chromogranin-A are present in majority of pulmonary neuroendocrine tumors and act as tumor marker. The mainstay of treatment is radical surgery if possible. In locally advanced or metastatic disease combination chemotherapy and somatostatin-analogues may have beneficial effect. This review focuses on the general features, and current diagnostic options of pulmonary neuroendocrine tumors. Orv. Hetil., 2011, 152, 366–370.

Neuroendocrine tumors of midgut and hindgut origin: tumor-node-metastasis classification determines clinical outcome

BACKGROUND

Prognostic classification of neuroendocrine tumor (NET) patients is difficult due to the complexity of current classification systems. A recent proposal for a tumor-node-metastasis (TNM) classification and a grading system based on the proliferative fraction proved valid in NETs of foregut origin. The purpose of this study was to test the efficacy of a proposal for TNM staging and grading for midgut and hindgut NETs.

METHODS

Two hundred seventy patients with histologically proven midgut and hindgut NETs were investigated. Epidemiological, clinicopathological, and tumor-specific data at initial diagnosis were recorded. Tumors were classified according to the World Health Organization (WHO) and the recent European Neuroendocrine Tumor Society-TNM staging and grading proposal. Survival analysis and statistical testing for independent prognostic factors were performed using log-rank tests and Cox regression.

RESULTS

Of 270 NETs originating in the midgut or hindgut, 7% (5-year survival rate [YSR], 100%) were stage 1, 8% (5-YSR, 100%) were stage 2, 19% (5-YSR, 89.5%) were stage 3, and 66% (5-YSR, 83.3%) were stage 4 NETs; 62% (5-YSR 95.2%) were grade 1, 32% (5-YSR 82.0%) were grade 2, and 6% (5-YSR, 51.4%) were grade 3 NETs. WHO classification significantly separated poorly from well-differentiated NET or carcinomas but did not further discriminate. TNM staging significantly separated stages 1, 2, and 3 from stage 4 NETs, as did grading according to proliferative capacity for all grades. Multivariate analysis confirmed these results, particularly for Ki67 grading.

CONCLUSIONS

The acquired data confirmed the prognostic relevance of the proposed TNM staging and grading system and demonstrated the applicability of these classification tools. The TNM system can therefore facilitate therapeutic stratification and comparison of data from different institutions.

Imaging of gastroenteropancreatic neuroendocrine tumors

Imaging of gastroenteropancreatic neuroendocrine tumors can be broadly divided into anatomic and functional techniques. Anatomic imaging determines the local extent of the primary lesion, providing crucial information required for surgical planning. Functional imaging, not only determines the extent of metastatic disease spread, but also provides important information with regard to the biologic behavior of the tumor, allowing clinicians to decide on the most appropriate forms of treatment. We review the current literature on this subject, with emphasis on the strengths of each imaging modality.

A case report of metastatic neuroendocrine carcinoma of the right adrenal gland successfully treated with chemotherapy and surgery

Poorly differentiated neuroendocrine carcinoma has a poor prognosis, especially when associated with distant metastasis. A 60-year-old man was admitted to a private hospital because of dyspnea at work in 2007. Computed tomography revealed lung infarction and a right adrenal tumor sized 12 cm in diameter that was tightly compressed against the inferior vena cava (IVC). Moreover, multiple lymph node metastases around the celiac axis and a solitary liver metastasis at the lateral segment were observed. Thus, we planned chemotherapy without surgery. We selected a combination therapy of irinotecan (CPT-11) and cisplatin (CDDP) (i.e., IP therapy): administration of CDDP [60 mg/m(2) body surface area (BSA)] on day 1 plus CPT-11 (80 mg/m(2)) BSA on days 1 and 8. Thereafter, this protocol was repeated at 3-week intervals. After 15 months of this chemotherapy strategy, the whole lesions showed a partial response by RECIST. The primary tumor had shrunk to 4.2 cm in diameter. In November 2008, we planned surgery to perform resection of the whole lesions. Histological diagnosis of the specimen was a poorly differentiated neuroendocrine carcinoma based on the immunostaining features, i.e., synaptophysin- and chromogranin positive. There were no viable tumor cells at the dissected lymph nodes or at the liver tumor. After surgery, CPT-11 administration was continued. The patient has remained well for 9 months without recurrence.

Incidence rates of exocrine and endocrine pancreatic cancers in the United States

Descriptive studies of pancreatic cancer incidence have been sparse particularly in terms of tumor histology and stage. The purpose of this study was to examine the incidence rate trends of exocrine and endocrine pancreatic cancers by demographic and tumor characteristics using data from the Surveillance, Epidemiology, and End Results (SEER) program from 1977 to 2005. During this period, the incidence of exocrine pancreatic cancer generally decreased whereas the incidence of endocrine pancreatic cancer increased. This difference in trends by histology was evident across age, gender, and racial groups. It was also evident among different racial/ethnic groups using data from 1992 to 2005. Variation in trends was observed by stage. The incidence of exocrine cancers declined for all stages except regional. Endocrine cancer incidence increased for all tumor stages, and the increase was most prominent for localized tumors. When exocrine tumors were stratified by tumor subsite, the incidence of cancers in the tail and body regions increased while the incidence in other regions decreased. While better detection and classification of tumors through improved diagnostic procedures may be related to these changing trends, etiologic factors warrant study.

EUS-FNA predicts 5-year survival in pancreatic endocrine tumors

BACKGROUND

Pancreatic endocrine tumors (PETs) differ in clinical behavior and prognosis. Determination of malignant potential through specimens obtained by EUS-FNA can help in the management of these patients.

OBJECTIVE

To determine the value of EUS-FNA for diagnosing PETs and for classifying their underlying malignant potential based on the World Health Organization (WHO) classification.

DESIGN

Single-center, retrospective, cohort study.

SETTING

Tertiary referral hospital.

PATIENTS

This study involved 86 consecutive patients (44 men, mean age 58 +/- 14 years) who had been diagnosed with PETs and submitted to EUS-FNA from January 1999 to August 2008.

INTERVENTION

EUS-FNA of a pancreatic mass and/or a metastasis site. Immunohistochemistry on microbiopsies or on monolayer cytology was routinely used. The lesions were classified as recommended by the WHO.

MAIN OUTCOME MEASUREMENTS

EUS-FNA sensitivity and 5-year survival rate.

RESULTS

Overall, in 90% (77 of 86) of patients in this study, PET was diagnosed with EUS-FNA. The sensitivity did not vary with tumor size, type, location, or the presence of hormonal secretion. Of 86 patients, 30 (35%) were submitted to surgical resection. The kappa correlation index between the WHO classification obtained by EUS-FNA and by surgery was 0.38 (P = .003). Major discrepancies were found in the group of patients diagnosed with endocrine tumor of uncertain behavior by EUS-FNA, because 72% turned out to have well-differentiated endocrine carcinoma. Sixteen patients (27%) died during a mean follow-up period of 34 +/- 27 months. The 5-year survival rates were 100% for endocrine tumors, 68% for well-differentiated endocrine carcinomas, and 30% for poorly differentiated endocrine carcinomas (P = .008, log-rank test).

LIMITATIONS

Retrospective design, selection bias, and small sample size.

CONCLUSIONS

This largest single-center experience to date demonstrated the accuracy of EUS-FNA in diagnosing and determining the malignant behavior of PETs. EUS-FNA findings predict 5-year survival in patients with PETs.

Neuroendocrine tumors of the pancreas

This literature review briefly summarizes the epidemiology, pathophysiology, clinical management, and outcomes of patients with pancreatic neuroendocrine tumors (PNETs) and highlights recent advances in PNET research. PNETs are rare neoplasms, compared with carcinomas arising from pancreatic exocrine tissue. They, like other neuroendocrine tumor types, display variable malignant potential, hormone-related syndromes (functionality), localization, and genetic background. Although tumor origin and molecular pathogenesis remain poorly understood, recently established grading and staging systems facilitate patient risk stratification, and thereby directly impact clinical decision making. Although the optimal clinical management of PNETs involves a multidisciplinary approach, surgery remains the only curative treatment for early-stage disease. Surgery may also have a role in patients with advanced-stage disease, including those with hepatic metastases. Alternative therapeutic approaches applied to PNETs, including chemotherapy, radiofrequency ablation, transarterial chemoembolization, biotherapy, polypeptide radionuclide receptor therapy, antiangiogenic therapy, and selective internal radiotherapy, have failed to demonstrate a long-term survival benefit. Surgery remains the primary therapeutic option for patients with PNETs. Research on PNETs is desperately needed to improve the therapeutic options for patients with this disease.

Neuroendocrine carcinoma of unknown primary site

Neuroendocrine carcinomas of unknown primary site are uncommon, diverse tumors with variable clinical behavior, predicted by tumor grade or differentiation. Most of these carcinomas probably arise from an occult/clinically undetectable primary site in one of several locations (bronchus, pancreas, stomach, colon, rectum and several other sites). Patients with these tumors are a subset of unknown primary carcinoma with relatively favorable prognoses. Low-grade or well-differentiated tumors are frequently indolent and cases should be managed similar to advanced carcinoid tumors. Targeted therapies may have a role in the treatment of low-grade tumors. The high-grade or poorly differentiated carcinomas, including small cell and large cell neuroendocrine tumors, are rapidly growing and aggressive but responsive to platinum-based combination chemotherapy. Poorly differentiated large cell neuroendocrine tumors, first reported in 1988, are usually not recognized by routine hematoxylin and eosin light microscopy but require immunohistochemical stains or electron microscopy for their diagnosis. A review of cytotoxic chemotherapy for patients with high-grade neuroendocrine carcinomas, including a series of 99 patients, revealed an overall response rate of 70%, with a 20% complete response rate. The median survival was 15 months, and a minority of patients (13%) had long-term survival. Tumor grade/differentiation currently is an important determinant of the management of these patients, and therapy in the future will be based on a more precise knowledge of the unique biology of these tumors.

Endocrine neoplasms of the pancreas: pathologic and genetic features

CONTEXT

Pancreatic endocrine neoplasms (PENs) are diagnostically challenging tumors whose natural history is largely unknown. Histopathology allows the distinction of 2 categories: poorly differentiated high-grade carcinomas and well-differentiated neoplasms. The latter include more than 90% of PENs whose clinical behavior varies from indolent to malignant and cannot be predicted by their morphology.

OBJECTIVES

To review the literature and report on additional primary material about the clinicopathologic features, classification, staging, grading, and genetic features of PENs.

DATA SOURCES

Literature review of relevant articles indexed in PubMed (US National Library of Medicine) and primary material from the authors' institution.

CONCLUSIONS

The diagnosis of PEN is generally easy, but unusual features may induce misdiagnosis. Immunohistochemistry solves the issue, provided that the possibility of a PEN has been considered. Morphology allows the distinction of poorly differentiated aggressive carcinomas from well-differentiated neoplasms. The World Health Organization classification criteria allow for the discernment of the latter into neoplasms and carcinomas with either benign or uncertain behavior. The recently proposed staging and grading systems hold great promise for permitting a stratification of carcinomas into clinically significant risk categories. To date, inactivation of the MEN1 gene remains the only ascertained genetic event involved in PEN genesis. It is inactivated in roughly one-third of PENs. The degree of genomic instability correlates with the aggressiveness of the neoplasm. Gene silencing by promoter methylation has been advocated, but a formal demonstration of the involvement of specific genes is still lacking. Expression profiling studies are furnishing valuable lists of mRNAs and noncoding RNAs that may advance further the research to discover novel markers and/or therapeutic targets.

Requiem for the term 'carcinoid tumour' in the gastrointestinal tract?

Use of the term 'carcinoid tumour' to describe a unique type of tumour in the gastroenteropancreatic system is endemic in the medical literature and in daily clinical and pathological parlance. However, it is a somewhat misleading moniker because a spectrum of histopathological changes and hence, biological outcomes may occur in these tumours. The World Health Organization classification scheme recommends the use of the terms neuroendocrine tumours or carcinomas, which may be stratified as well-differentiated neuroendocrine tumours with benign or uncertain behaviour, well-differentiated tumours with low-grade neuroendocrine carcinoma behaviour and high-grade neuroendocrine carcinomas. These categories may be applied within different sites in the gastrointestinal tract and pancreas, and convey a sense of biological behaviour. In addition, a recently suggested tumour-node-metastasis scheme has been proposed and awaits clinical validation and acceptance. Thus, the term 'carcinoid' has served its purpose well, but its use should be phased out in favour of 'neuroendocrine tumour' or 'neuroendocrine carcinoma'.

Staging and survival analysis for nonsquamous cell carcinomas of the larynx

OBJECTIVE

Determine staging and comparative survival for nonsquamous cell carcinoma (SCC) of the larynx.

STUDY DESIGN

Cross-sectional population analysis.

METHODS

: Cases of non-SCC supraglottic, glottic, and subglottic cancers were extracted from the Surveillance, Epidemiology and End Results database (1988-2003) and the staging distribution computed. For each site, Kaplan-Meier survivals were compared according to histology, T-stage, and N-stage. Survival for non-SCC cancers for each site were compared among histologies, T-stage, and N-stage as well as with age/sex/stage-matched SCC cancers to determine differences in survival.

RESULTS

One hundred forty supraglottic non-SCC cases were identified (67% male, mean age 62.0 yr) consisting of 25 neuroendocrine, 25 small cell, and 22 lymphomas (among others), with mean survivals of 44.8, 52.1, and 80.5 months, respectively. Survival was not significantly different according to histology (log-rank, P = .440) but was significantly different according to T-stage (P = .029) and N-stage (P < .001). Seventy-eight glottic non-SCC cases were identified (83% male, mean age 66.1 yr) consisting of 32 spindle cell, 13 sarcoma, and 10 small cell (among others), with mean survivals of 114.6, 89.8, and 39.2 months, respectively. Survival was not significantly different according to histology (P = .056) but was significantly different according to T-stage (P = .002) and N-stage (P = .022). Small numbers (26) precluded subglottic analysis. For both supraglottic and glottic sites including all histologies, survival was similar for matched non-SCC and SCC cases (P = .510 and P = .930, respectively).

CONCLUSIONS

Non-SCCs are more common in the supraglottic larynx. T-stage and N-stage influence survival more than histology alone for these cancers.

Diagnostic and prognostic implications of the World Health Organization classification of neuroendocrine tumors

BACKGROUND

Neuroendocrine differentiation of tumors is often difficult to establish. In the same manner, the evaluation of the prognostic role of neuroendocrine differentiation may constitute a relevant clinical problem. Although different classifications are used for neuroendocrine tumors (NET) of different origin, the last World Health Organization (WHO) classification of NET, originally proposed for gastroenteropancreatic tumors, has proved to be a practical tool to allow pathologists to uniform the diagnoses and re-classify these tumors into 3 main categories.

AIM

The present study was carried out in order to evaluate diagnostic and prognostic implications of NET reclassification according to the last WHO classification of NET.

MATERIALS AND METHODS

Thirty-one tumors with an initial diagnosis referable to a NET achieved before 1999 were independently evaluated by 3 pathologists on the basis of the 2000 WHO classification of NET. Immunohistochemistry for panneuroendocrine markers and Ki-67 was also performed in all cases.

RESULTS

Twelve, 14, and 4 tumors were respectively reclassified as well-differentiated NET, well-differentiated neuroendocrine carcinoma and poorly differentiated neuroendocrine carcinoma; 1 tumor was reclassified as mixed endocrine-exocrine tumor. Two or more neuroendocrine markers were expressed in all NET regardless of histotype, differentiation degree, and site of primary tumor. After revision, 10 of the 31 tumors under study (32%) changed histo-prognostic category when compared to the initial diagnosis. Ki-67 score was the best predictor of survival at the multivariate analysis.

CONCLUSION

The WHO classification is suitable to accurately reclassify tumors with an initial diagnosis referable to a NET and to separate these tumors in 3 well-distinct histo-prognostic categories with relevant clinical implications. Ki-67 score seems to be a better predictor of survival than the degree of differentiation.

TNM staging of midgut and hindgut (neuro) endocrine tumors: a consensus proposal including a grading system

Criteria for the staging and grading of neuroendocrine tumors (NETs) of midgut and hindgut origin were established at the second Consensus Conference in Frascati (Rome) organized by the European Neuroendocrine Tumor Society (ENETS). The proposed tumor-node-metastasis (TNM) classifications are based on the recently published ENETS Guidelines for the Diagnosis and Treatment of gastroenteropancreatic NETs and follow our previous proposal for foregut tumors. The new TNM classifications for NETs of the ileum, appendix, colon, and rectum, and the grading system were designed, discussed, and consensually approved by all conference participants. These proposals need to be validated and are meant to help clinicians in the stratification, treatment and follow-up of patients.

Chemo-hormone therapy of non-well-differentiated endocrine tumours from different anatomic sites with cisplatinum, etoposide and slow release lanreotide formulation

We report the results of a phase II trial in patients with metastatic endocrine tumours from different sites, which aimed to evaluate the anti-tumour activity and toxicity of a cisplatinum and etoposide regimen administered in combination with the somatostatin agonist lanreotide given in slow release formulation. Between January 1999 and November 2003, 27 patients with histological diagnoses of endocrine tumours with different degrees of differentiation, excluding well differentiated carcinoid neoplasms, received intravenous (i.v.) administration of cisplatinum (30 mg m⁻²) and etoposide (100 mg m⁻²) on days 1–3 and intramuscular administration of 60 mg lanreotide on day 1, in a 21-day cycle. All of the patients were evaluable for toxicity and response. The treatment was very well tolerated as no grade 4 toxicity was observed. Four patients achieved a complete response, six a partial response, 12 experienced disease stabilisation and five disease progression. The average time to progression and to survival were 9 and 24 months respectively. These results suggest that this chemo-hormone therapy regimen is well tolerated and active in patients with non-well differentiated endocrine tumours.

Prognostic factors in gastrointestinal endocrine tumors

The gastrointestinal endocrine tumors are neoplastic lesions with often elusive malignant clinical behavior. The current WHO classification attempted to define a more effective approach by introducing the concepts of cell differentiation and site-specific malignancy, as well as specific criteria for carcinoma definition. WHO clinicopathological correlations embed the prognostic features: degree of cell differentiation, angioinvasion, proliferation fraction as assessed by mitotic index and Ki67, size, and functional activity. Other prognostic variables have been recognized, most of which related to specific biological features of neuroendocrine cancer cells. Nonetheless, the presence of liver or distant metastases are the prognostic variables ultimately determining the patients' fate in terms of survival and/or therapy response. A recent proposal of tumor grading and tumor, nodes, and metastases (TNM) staging aims at a simple and practical system for patients stratification. Application of such proposal should be implemented in routine clinical practice.

TNM staging of foregut (neuro)endocrine tumors: a consensus proposal including a grading system

The need for standards in the management of patients with endocrine tumors of the digestive system prompted the European Neuroendocrine Tumor Society (ENETS) to organize a first Consensus Conference, which was held in Frascati (Rome) and was based on the recently published ENETS guidelines on the diagnosis and treatment of digestive neuroendocrine tumors (NET). Here, we report the tumor–node–metastasis proposal for foregut NETs of the stomach, duodenum, and pancreas that was designed, discussed, and consensually approved at this conference. In addition, we report the proposal for a working formulation for the grading of digestive NETs based on mitotic count and Ki-67 index. This proposal, which needs to be validated, is meant to help clinicians in the stratification, treatment, and follow-up of patients.

Are capecitabine and oxaliplatin (XELOX) suitable treatments for progressing low-grade and high-grade neuroendocrine tumours?

PURPOSE

The aim of this trial was to evaluate the safety and efficacy of oxaliplatin and capecitabine (XELOX) in neuroendocrine tumours' (NETs) treatment.

METHODS

Forty patients (pts) with advanced NETs were treated. Of these, 13 had untreated poorly differentiated NETs, 27 had well-differentiated NETs in progression after somatostatin analogues. Patients received oxaliplatin e.v. 130 mg/mq i.v. and capecitabine 2,000 mg/mq/die. The primary sites of the disease were: lung (10 pts), pancreas (15 pts), small bowel (8 pts), unknown (1 pt), others (6 pts).

RESULTS

In 13 pts with poorly differentiated NETs objective responses (OR) were: 3 PR (23%), 1 SD (7%), 9 PD (70%). Biochemical responses were 11%. In 27 patients with well-differentiated NETs the OR were: 8 PR (30%), 13 SD (48%) and 6 PD (22%). Biochemical and symptomatic responses were 20 and 50%, respectively.

CONCLUSIONS

The XELOX regimen is effective and tolerated in well-differentiated NETs after progression following somatostatin analogues.

Long-term clinical outcome of somatostatin analogues for treatment of progressive, metastatic, well-differentiated entero-pancreatic endocrine carcinoma

BACKGROUND

Knowledge of factors able to predict the clinical outcome of homogenous series of entero-pancreatic endocrine tumours treated with somatostatin analogues is poor. This study was aimed at identifying predictors for efficacy of somatostatin analogues at inhibiting tumour growth and modifying patients' survival during long-term follow-up.

PATIENTS AND METHODS

31 patients with entero-pancreatic well-differentiated endocrine carcinoma received long-acting somatostatin analogues. All had progressive, metastatic disease (87% liver metastases, 38.7% distant extra-hepatic metastases).

RESULTS

Response rate after 6 months of treatment was 45.2% (all disease stabilisation: 27.8% of pancreatic vs. 81.8% of intestinal tumours, P = 0.007). The predictors for non-response were: pancreatic tumour (OR 5.8), no previous surgery (OR 6.7), and the presence of distant extra-hepatic metastases, the latter being also confirmed by multivariate analysis (OR 10.0). Responders maintained stabilisation for 26.5 months, and none died during follow-up. Different survival curves were observed for patients, responding at 6 months compared to non-responders (P = 0.004), 3-year survival rate being 100% and 52.3%, respectively.

CONCLUSIONS

Distant extra-hepatic metastases are the major predictor of poor efficacy of somatostatin analogues in progressive, metastatic, well-differentiated entero-pancreatic endocrine carcinomas. Patients achieving response after 6 months of treatment, maintain it throughout a long-term follow-up. Non-responders after 6 months of treatment, have a worse survival, and should be considered for alternative treatments.