Classification and pathology of gastroenteropancreatic neuroendocrine neoplasms

A competing-risks nomogram and recursive partitioning analysis for cause-specific mortality in patients with esophageal neuroendocrine carcinoma

The objective of this study is to estimate the probability of cause-specific mortality using a competing-risks nomogram and recursive partitioning analysis in a large population-based cohort of patients with esophageal neuroendocrine carcinoma. The surveillance, epidemiology and end results database was used to identify 162 patients diagnosed with esophageal neuroendocrine carcinoma from 1998 to 2014. We estimated a cumulative incidence function for cause-specific mortality. A nomogram was constructed by using a proportional subdistribution hazard model, validated using bootstrap cross-validation, and evaluated with a decision curve analysis to assess its clinical utility. Finally, we performed risk stratification using a recursive partitioning analysis to divide patients with esophageal neuroendocrine carcinoma into clinically useful prognostic groups. Tumor location, distant metastasis, surgery, radiotherapy, and chemotherapy were significantly associated with cause-specific mortality. The calibration plots demonstrated good concordance between the predicted and actual outcomes. The discrimination performance of a Fine-Gray model was evaluated by using the c-index, which was 0.723 for cause-specific mortality. The decision curve analysis ranged from 0.268 to 0.968 for the threshold probability at which the risk model provided net clinical benefits relative to hypothetical all-screening and no-screening scenarios. The risk groups stratified by a recursive partitioning analysis allowed significant distinction between cumulative incidence curves. We determined the probability of cause-specific mortality in patients with esophageal neuroendocrine carcinoma and developed a nomogram and recursive partitioning analysis stratification system based on a competing-risks model. The nomogram and recursive partitioning analysis appear to be suitable for risk stratification of cause-specific mortality in patients with esophageal neuroendocrine carcinoma and will help clinicians to identify patients at increased risk of cause-specific mortality to guide treatment and surveillance decisions.

The Role of PET/CT in the Imaging of Pancreatic Neoplasms

Pancreas cancer is a complex disease and its prognosis is related to the origin of the tumor cell as well as the stage of disease at the time of diagnosis. Pancreatic adenocarcinomas derive from the exocrine pancreas and are the fourth leading cause of cancer-related deaths in the United States, while well-differentiated pancreatic neuroendocrine tumors (pNETs) derived from the endocrine part of the pancreas are rare and characterized by a slow growth and good life expectancy. Surgery is the only curative treatment approach, and an accurate assessment of resectability is of paramount importance in order to avoid futile procedures. The role of molecular imaging with positron emission tomography and computed tomography ranges from indispensable for pNETs to controversial for certain scenarios in pancreatic adenocarcinomas. This review article aims to overview molecular pancreatic imaging.

Magnetic Resonance of Small Bowel Tumors

Tumors of the small intestine represent less than 5% of all gastrointestinal tract neoplasms. Magnetic resonance (MR) imaging is rapidly increasing clinical acceptance to evaluate the small bowel and can be the initial imaging method to investigate small bowel diseases. MR examinations may provide the first opportunity to detect and characterize tumors of the small bowel. Intraluminal and extraluminal MR findings, combined with contrast enhancement and functional information, allow accurate diagnoses and consequently characterization of small bowel neoplasms. This article describes the MR findings of primary small bowel neoplasms and the MR findings for the differential diagnosis are discussed.

Is There a Role for Surgery in Patients with Neuroendocrine Tumors of the Esophagus? A Contemporary View from the NCDB

BACKGROUND

Esophageal neuroendocrine tumors (eNETs) are exceedingly rare, aggressive and have a poor prognosis. Treatment guidelines are ill-defined and mainly based on evidence from case reports and analogous experiences drawn from similar disease sites.

METHODS

The NCDB was reviewed for histologically confirmed stage I-III, primary eNETs from 2006 to 2014. Patients were grouped into whether or not they underwent primary tumor resection. Univariate, multivariable, and full bipartite propensity score (PS) adjusted Cox regression analyses were used to assess overall and relative survival differences.

RESULTS

A total of 250 patients were identified. Mean age was 65.0 (standard deviation [SD] 11.9) years, and 174 (69.6%) patients were male. Most patients had stage III disease (n = 136, 54.4%), and the most common type of NET was small cell eNET (n = 111, 44.4%). Chemotherapy was used in 186 (74.4%), radiation therapy in 178 (71.2%), and oncological resection was performed in 69 (27.6%) patients. Crude 2-year survival rates were higher in the operated (57.3%) compared with the nonoperated group (35.2%; p < 0.001). The survival benefit held true after multivariable adjustment (hazard ratio [HR] 0.47, 95% confidence interval [CI] 0.32-0.69, p < 0.001). After full bipartite PS adjustment analysis, survival was longer for patients who received a surgical resection compared with those who did not (HR 0.48, 95% CI 0.31-0.75, p = 0.003) with a corresponding 2-year overall survival rate of 63.3% (95% CI 52.0-77.2) versus 38.8% (95% CI 30.9-48.8), respectively.

CONCLUSIONS

Multimodal treatment that includes surgery is associated with better overall survival for eNETs. Additional research is needed to more definitively identify patients who benefit from esophagectomy and to establish an appropriate treatment algorithm.

Hedinger syndrome: first experience and two-year follow-up in patients with carcinoid heart disease

Background

Carcinoid heart disease (CHD) (Hedinger syndrome) is a rare manifestation, it has been described in up to 60% of patients with both neuroendocrine tumors (NETs) and carcinoid syndrome (CS) which, typically inducing right heart-sided abnormalities.

Methods

Between 07/15 and 10/18, six patients (mean age 63±12 years; 3 females) presented with manifested (NYHA III-IV) Hedinger syndrome's related valvular(s) lesion and were operated at our center. Clinical data, adverse events and patient outcomes were recorded.

Results

The tricuspid valve was involved in all patients. Tricuspid valve repair was possible in four patients and two needed replacement. In two patients, operation was performed on beating heart without cross-clamping. Concomitant pulmonary valve replacement in two patients and aortic valve replacement in another two patients. A mean cross-clamp time of 61±50 minutes was observed. One patient with severely impaired right ventricular function needed ECMO support, and died 3 days later due to neuroendocrine enzyme storm. At 13 months, one patient developed severe tricuspid stenosis and underwent re-operation with replacement. Another patient died 18 months after surgery related to the underlying tumour. At mean of 30 months follow-up, four patients were alive and asymptotic.

Conclusions

Hedinger syndrome is a challenging entity in cardiac surgery characterized by aggressive valve lesions combined with metastatic neuroendocrine neoplasia affecting the systemic circulation. We advise a multidisciplinary collaboration to early diagnose cardiac involvement to offer an early and proper treatment regime.

The tumor immune microenvironment in gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a group of rare tumors that are increasing in prevalence. The complex tumor immune microenvironment (TIME) plays an important role in tumor development and the response to immunotherapy but is poorly understood. In this review, the components of the TIME are described in detail, including discussion about infiltrating immune cells, the immune checkpoint system, the cytokine and chemokine milieu, and immunomodulatory factors. Moreover, a comparison between TIMEs among different types of GEP-NENs and the interplay among the TIME, tumor cells, and the stromal microenvironment is described. Novel treatment options for GEP-NENs and potential biomarkers for the immune response are also characterized. We provide a comprehensive generalized review of the TIME that can inform GEP-NEN treatment strategies.

Neuroendocrine Tumors in Pediatrics

Neuroendocrine cells are dispersed diffusely throughout many organ systems in the body and hence neuroendocrine tumors (NETs) can arise from almost anywhere in the body. NETs are considered rare tumors, and the current incidence is reported to be about 6 cases in 100 000 in adults and about 2.8 cases per million in the pediatric age group. Despite the indolent nature of these tumors, they have the potential for metastasis and significant morbidity. NETs can be asymptomatic at the time of diagnosis or can present with flushing, diarrhea, wheezing, weight loss, and fatigue among other symptoms. Due to the ambiguity of presenting symptoms, it is not uncommon for NETs to be diagnosed late in the disease course. Despite low incidence, the prevalence of the disease is high since patients live for many years and sometimes decades. Early detection of well-differentiated NETs has excellent outcomes with the majority of early-stage diseases being cured with surgical resection alone. There have been recent advancements in the management of metastatic progressive NETs with approval of peptide receptor radionuclide therapy, telotristat, and everolimus. Awareness of these rare tumors and its management is crucial for optimal management. This article will focus on pediatric NETs and current advances in its management.

Indications for resection and perioperative outcomes of surgery for pancreatic neuroendocrine neoplasms in Germany: an analysis of the prospective DGAV StuDoQ|Pancreas registry

PURPOSE

Pancreatic neuroendocrine neoplasms (pNENs) are rare, and their surgical management is complex. This study evaluated the current practice of pNEN surgery across Germany, including its adherence with guidelines and its perioperative outcomes.

METHODS

Patients who underwent surgery for pNENs (April 2013-June 2017) were retrieved from the prospective StuDoQ|Pancreas registry of the German Society of General and Visceral Surgery and retrospectively analyzed.

RESULTS

A total of 287 patients (53.7% male) with a mean age of 59.2 ± 14.2 years old underwent pancreatic resection for pNENs. Tumors were localized in the pancreatic head (40.4%), body (23%), or tail (36.6%). A total of 239 (83.3%) patients underwent formal resection with lymphadenectomy, 40 (14%) parenchyma-sparing resection, and 8 (2.8%) only exploration. Fifty (17.4%) patients underwent a minimally invasive approach. Among the 245 patients with complete pathological information, 42 (17.1%) had distant metastases, 78 (31.8%) had stage I tumors, 74 (30.2%) stage II, and 51 (20.8%) stage III. A total of 112 (45.7%) patients had G1 tumors, 101 (41.2%) G2, and 24 (9.8%) G3. Nodal involvement on imaging was an independent predictor of lymph node metastasis according to the multivariable analysis (odds ratio: 0.057; 95% confidence interval: 0.016-0.209; p < 0.01). R0 resection was reported in 240 (83.6%) patients. The 30- and 90-day mortality rates were 2.8% and 4.2%, respectively.

CONCLUSION

In Germany the rate of potential curative resection for pNEN is high. However, formal pancreatic resection seems to be overrepresented, while minimally invasive resection is underrepresented.

Minimally invasive versus open distal pancreatectomy for pancreatic neuroendocrine tumors: An analysis from the U.S. neuroendocrine tumor study group

BACKGROUND

To determine short- and long-term oncologic outcomes after minimally invasive distal pancreatectomy (MIDP) with open distal pancreatectomy (ODP) for the treatment of pancreatic neuroendocrine tumor (pNET).

METHODS

The data of the patients who underwent curative MIDP or ODP for pNET between 2000 and 2016 were collected from a multi-institutional database. Propensity score matching (PSM) was used to generate 1:1 matched patients with MIDP and ODP.

RESULTS

A total of 576 patients undergoing curative DP for pNET were included. Two hundred and fourteen (37.2%) patients underwent MIDP, whereas 362 (62.8%) underwent ODP. MIDP was increasingly performed over time (2000-2004: 9.3% vs 2013-2016: 54.8%; P < 0.01). In the matched cohort (n = 141 in each group), patients who underwent MIDP had less blood loss (median, 100 vs 200 mL, P < 0.001), lower incidence of Clavien-Dindo ≥ III complications (12.1% vs 24.8%, P = 0.026), and a shorter hospital stay versus ODP (median, 4 versus 7 days, P = 0.026). Patients who underwent MIDP had a lower incidence of recurrence (5-year cumulative recurrence, 10.1% vs 31.1%, P < 0.001), yet equivalent overall survival (OS) rate (5-year OS, 92.1% vs 90.9%, P = 0.550) compared with patients who underwent OPD.

CONCLUSION

Patients undergoing MIDP over ODP in the treatment of pNET had comparable oncologic surgical metrics, as well as similar long-term OS.

The landscape of molecular alterations in pancreatic and small intestinal neuroendocrine tumours

Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs) arise throughout the gut and feature varying biological behaviour and malignant potential. GEP-NENs include two genetically different entities, well-differentiated neuroendocrine tumours (NETs) and poorly differentiated neuroendocrine carcinomas (NEC). NECs are characterized by a dismal prognosis and by distinctive TP53 and RB1 inactivation which sets them apart from NETs. The latter, conversely, have a wide spectrum of aggressiveness and molecular alterations. Knowledge on their biology has recently expanded thanks to high-throughput studies focused on two important groups of well-differentiated neuroendocrine neoplasms: pancreatic (PanNETs) and small intestinal (SiNETs) tumours. PanNETs have been among the most studied also due to genetic syndromes featuring their onset. Research stemming from this observation has uncovered the inactivation of MEN1, VHL, TSC1/2, and the hyperactivation of the PI3K/mTOR pathway as distinctive biological features of these neoplasms. Next-Generation Sequencing added information on the role of telomere lengthening via ATRX/DAXX inactivation in a fraction of PanNETs, while other display shortened telomeres and recurrent chromosomal alterations. The data so far disclosed a heterogeneous combination of driver events, yet converging into four pathways including DNA damage repair, cell cycle regulation, PI3K/mTOR signalling and telomere maintenance. SiNETs showed a lesser relationship with mutational driver events, even in the case of familial cases. High throughput studies identified putative driver mutations in CDKN1 and APC which, however, were reported in a minor fraction (∼10%) of cases. Tumorigenesis of SiNETs seems to depend more on chromosomal alterations (loss of chromosome 8, gains at 4, 5 and 20) and epigenetic events, which converge to hyperactivate the PI3K/mTOR, MAPK and Wnt pathways. While calling for further integrative studies, these data lay previous and recent findings in a more defined frame and provide clinical research with several candidate markers for patient stratification and companion diagnostics.

Palliative Radiation Therapy for Bone Metastases in Neuroendocrine Neoplasms

Purpose

Bone metastases are reported in 10% to 12% of patients with neuroendocrine neoplasms (NENs) and can lead to pain and skeletal-related events (SREs), resulting in diminished quality of life and functional status. In other solid tumors with bone metastases, radiation therapy (RT) is an established treatment approach for SREs, yet few data are available in NENs historically considered to be radioresistant. We hypothesize that RT is effective for pain and other SREs in NENs and aimed to delineate any differences in pain palliation and time until progression of pain between different fractionation and dosing schedules of RT.

Methods and Materials

We retrospectively reviewed 686 records of patients with NENs treated at the institution between 2011 and 2018 and identified 28 (4.1%) patients treated with RT for 61 cases of SREs. The primary endpoint was change in patient reported pain scores after RT.

Results

All 28 patients experienced bone pain. Nineteen sites were treated with a single fraction (doses of 800-1800 cGy) and 42 sites with fractionated regimens (doses of 900-3750 cGy over 3-15 fractions). In 55 of 61 cases (90%), patients experienced improvement in pain after RT. The median time to recurrence or progression of pain was 3.5 months. Significant differences were found between primary site and change in performance status (P = .024), sex, and reported magnitude of pain score decrease after RT (P = .025). There were no differences in the time to the progression of pain, change in performance status, and degree of improvement in pain based on age, chemotherapy received during RT, or radiation site. Outcomes were similar for patients who received single-fraction versus fractionated regimens (P = .545) and between those receiving palliative versus ablative RT regimens (P = .812).

Conclusions

Although the majority of cases in this NEN cohort benefited from RT, additional studies on the use of RT in the treatment of painful bone metastases are warranted.

Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.

Genomic dissection of gastrointestinal and lung neuroendocrine neoplasm

Objective

Neuroendocrine neoplasms (NENs) are relatively rare and heterogeneous malignancies with two major subtypes: low-grade neuroendocrine tumor (NET) and high-grade neuroendocrine carcinoma (NEC). Comprehensive molecular characterization of NENs is needed to refine our understanding of the biological underpinnings of different NEN subtypes and to predict disease progression more accurately.

Methods

We performed whole-exome sequencing (WES) of NEN samples from 49 patients (25 NETs and 24 NECs) arising from the stomach, intestines or lung. Clinicopathologic features were assessed and associated with molecular events.

Results

NENs generally harbor a low mutation burden, with TP53 being the top mutated gene found in 31% of patients. Consistent with other studies, p53 signaling pathway dysfunction is significantly enriched in NECs compared to NETs (P<0.01). Other thanTP53, tissue type-specific mutation profiles of NENs were observed in our cohort compared to those reported in pancreatic NETs. Importantly, we observed significant genomic instability, with increased copy number alterations observed across the NEN genome, which was more profound in NECs and independently correlated with poor overall survival (OS) (P<0.001). NECs could be further stratified into two molecular subtypes based on OS (P<0.001) and the chromosomal instability score (CIS). Interestingly, we discovered that the gain of whole chromosome 5 occurred at the early stage of NEN development, followed by the loss of 5q exclusively in NECs (P<0.001).

Conclusions

These findings provide novel insights into the molecular characteristics of NENs and highlight the association of genomic stability with clinical outcomes.

Patterns of Recurrence after Resection for Pancreatic Neuroendocrine Tumors: Who, When, and Where?

BACKGROUND/AIMS

Pancreatic neuroendocrine tumors (pan-NENs) represent an increasingly common indication for pancreatic resection, but there are few data regarding possible recurrence after surgery. The aim of the study was to describe the frequency, timing, and patterns of recurrence after resection for pan-NENs with consequent implications for postoperative follow-up.

METHODS

We performed a retrospective analysis of pan-NENs resected between 1990 and 2015 at The Pancreas Institute, University of Verona Hospital Trust. Predictors of recurrence were assessed. Survival analysis was conducted using the Kaplan-Meier and conditional survival (CS) methods.

RESULTS

The cohort consisted of 487 patients with a median follow-up of 71 months. Recurrence developed in 12.3%: 54 (11.1%) liver metastases, 11 (2.3%) local recurrence, 10 (2.1%) nodal recurrence, and 8 (1.6%) metastases in other organs. Thirty-one (6.4%) died due to disease recurrence. Size > 21 mm, G3 grade, nodal metastasis, and vascular infiltration were independent predictors of overall recurrence. Recurrence occurred either during the first year of follow-up (n = 9), or after 10 years (n = 4). CS analysis revealed that nonfunctioning G1 pan-NEN ≤20 mm without nodal metastasis or vascular invasion had a negligible risk of developing recurrence. In the present series, after 5 years of follow-up without developing recurrence, tumor recurrence occurred only in the form of liver metastases.

CONCLUSIONS

Recurrence of pan-NENs is rare and is predicted by tumor size, nodal metastasis, grading, and vascular invasion. Patients with G1 pan-NEN without nodal metastasis and vascular invasion may be considered cured by surgery. After 5 years without recurrence, follow-up should focus on excluding the development of liver metastases.

Neoplasms of the Neuroendocrine Pancreas: An Update in the Classification, Definition, and Molecular Genetic Advances

This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of "well-differentiated high-grade NET (G3)" to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary.

Role of the tumor microenvironment in digestive neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) represent a group of heterogeneous tumors whose incidence increased over the past few years. Around half of patients already present with metastatic disease at the initial diagnosis. Despite extensive efforts, cytotoxic and targeted therapies have provided only limited efficacy for patients with metastatic GEP-NETs, mainly due to the development of a certain state of resistance. One factor contributing to both the failure of systemic therapies and the emergence of an aggressive tumor phenotype may be the tumor microenvironment (TME), comprising dynamic and adaptative assortment of extracellular matrix components and non-neoplastic cells, which surround the tumor niche. Accumulating evidence shows that the TME can simultaneously support both tumor growth and metastasis and contribute to a certain state of resistance to treatment. In this review, we summarize the current knowledge of the TME of GEP-NETs and discuss the current therapeutic agents that target GEP-NETs and those that could be of interest in the (near) future.

Pancreatic neuroendocrine tumor: review of heterogeneous spectrum of CT appearance

OBJECTIVE

Pancreatic neuroendocrine tumors (PanNETs) are uncommon pancreatic neoplasms and can be a diagnostic challenge with heterogeneous spectrum of CT appearance. We review CT findings of PanNETs and other mimics.

CONCLUSION

PanNETs are typically hypervascular and have avid enhancement on arterial and venous phase images. However, dedicated pancreas protocol may be needed due to their sometimes atypical appearance including transient enhancement. Careful evaluation of CT findings will help differentiate PanNETs from their mimics, and can be used to establish the diagnosis of a PanNETs. Although an accurate diagnosis can be based on serological, urine, and CT scan findings, confirmation is made via pathological examination.

The Role of Surgery in Treating Resectable Limited Disease of Esophageal Neuroendocrine Carcinoma

BACKGROUND

Esophageal neuroendocrine carcinoma (NEC) is a rare malignant tumor. The role of surgery in resectable limited disease of esophageal NEC remains unclear. How to select a specific group of limited disease of esophageal NEC who might benefit from surgery remains to be answered.

METHODS

Patients undergoing esophagectomy for resectable limited disease of esophageal NEC in our department from January 2007 to June 2015 were analyzed. TNM staging system was applied to describe those patients, and according to their different long-term prognosis after surgery, those patients were subgrouped into surgery response limited disease (SRLD) group and surgery non-response limited disease (SNRLD) group. Both univariate and multivariate analyses were applied to identify potential prognostic factors.

RESULTS

A total of 72 patients with resectable limited disease of esophageal NEC were identified for analysis. The median survival time of those patients was 21.5 months. There was no significant survival differences among stage I, stage IIA, and stage IIB patients, but all these patients had significantly longer survival than stage III patients. Therefore, stage I, stage IIA, and stage IIB patients were aggregated together as SRLD group, and stage III patients were aggregated as SNRLD group. SRLD patients obtained significantly longer survival than SNRLD patients in both univariate analysis and multivariate analysis. Moreover, adjuvant therapy could significantly benefit SRLD patients (P = 0.004) but could not benefit SNRLD patients (P = 0.136).

CONCLUSIONS

Different responses to surgery existed in resectable limited disease of esophageal NEC indicating the need of further subgrouping for those patients. The resectable limited disease of esophageal NEC could be further subgrouped into SRLD group and SNRLD group according to the TNM staging system.

Preoperative 68Ga-DOTA-Somatostatin Analog-PET/CT Hybrid Imaging Increases Detection Rate of Intra-abdominal Small Intestinal Neuroendocrine Tumor Lesions

Background

Small intestinal neuroendocrine tumors (SI-NETs) are the most common form of neoplasm in the small bowel. Radiological identification of primary tumors (PT), which may be multiple, is difficult, and therefore palpation of the entire small bowel is routinely performed during laparotomy. The aim was to determine detection rates of PT and peritoneal carcinomatosis (PC) with ⁶⁸Ga-DOTATOC/TATE-PET/CT in comparison with i.v. contrast-enhanced computed tomography (CE-CT) and thus to clarify whether modern functional imaging can mitigate the need for palpation of bowel during surgery enabling oncologically adequate laparoscopic resection.

Methods

A total of 28 patients with SI-NET who preoperatively underwent both ⁶⁸Ga-DOTATOC/TATE-PET/CT and CE-CT were included. The detection rates of PT and PC for PET/CT and CE-CT were compared to the findings in the surgical and histopathological reports. Appropriate statistical tests were used, and significance was set to p < 0.05.

Results

Out of 82 PT, 43 PT were not detected by any imaging modality. More PT lesions were detected with PET/CT (n = 39 [47.5%]) than with CE-CT (n = 10 [12.2%], p < 0.001). Also, PET/CT identified significantly more PC lesions than CE-CT (78 and 38%, p = 0.004, respectively).

Conclusion

PET/CT detected more PT and PC lesions than CE-CT. Some PTs and PC lesions were only detected by one of the modalities, and CT performed in conjunction with PET/CT should therefore be performed as a fully diagnostic CE-CT for optimal results. Palpation of the small bowel remains crucial during surgery in these patients because several PTs escaped detection by both PET/CT and CE-CT.

Current Management of Pancreatic Neuroendocrine Tumors: From Demolitive Surgery to Observation

Incidental diagnosis of pancreatic neuroendocrine tumors (PanNETs) greatly increased in the last years. In particular, more frequent diagnosis of small PanNETs leads to many challenging clinical decisions. These tumors are mostly indolent, although a percentage (up to 39%) may reveal an aggressive behaviour despite the small size. Therefore, there is still no unanimity about the best management of tumor smaller than 2 cm. The risks of under/overtreatment should be carefully evaluated with the patient and balanced with the potential morbidities related to surgery. The importance of the Ki-67 index as a prognostic factor is still debated as well. Whenever technically feasible, parenchyma-sparing surgeries lead to the best chance of organ preservation. Lymphadenectomy seems to be another important prognostic issue and, according to recent findings, should be performed in noninsulinoma patients. In the case of enucleation of the lesion, a lymph nodal sampling should always be considered. The relatively recent introduction of minimally invasive techniques (robotic) is a valuable option to deal with these tumors. The current management of PanNETs is analysed throughout the many available published guidelines and evidences with the aim of helping clinicians in the difficult decision-making process.

Somatostatin Analogue Treatment Primarily Induce miRNA Expression Changes and Up-Regulates Growth Inhibitory miR-7 and miR-148a in Neuroendocrine Cells

Somatostatin (SST) analogues are used to control the proliferation and symptoms of neuroendocrine tumors (NETs). MicroRNAs (miRNA) are small non-coding RNAs that modulate posttranscriptional gene expression. We wanted to characterize the miRNAs operating under the control of SST to elucidate to what extent they mediate STT actions. NCI-H727 carcinoid cell line was treated with either a chimeric SST/dopamine analogue; a SST or dopamine analogue for proliferation assays and for identifying differentially expressed miRNAs using miRNA microarray. The miRNAs induced by SST analogue treatment are investigated in carcinoid cell lines NCI-H727 and CNDT2 using in situ hybridization, qPCR and proliferation assays. SST analogues inhibited the growth of carcinoid cells more potently compared to the dopamine analogue. Principal Component Analysis (PCA) of the samples based on miRNA expression clearly separated the samples based on treatment. Two miRNAs which were highly induced by SST analogues, miR-7 and miR-148a, were shown to inhibit the proliferation of NCI-H727 and CNDT2 cells. SST analogues also produced a general up-regulation of the let-7 family members. SST analogues control and induce distinct miRNA expression patterns among which miR-7 and miR-148a both have growth inhibitory properties.

Fast non-enhanced abdominal examination protocols in PET/MRI for patients with neuroendocrine tumors (NET): comparison to multiphase contrast-enhanced PET/CT

PURPOSE

To evaluate fast non-enhanced protocols for abdominal PET/MRI in comparison to contrast-enhanced PET/CT with somatostatin receptor (SSR)-specific radiotracers regarding effectiveness of lesion detection in NET patients.

METHODS

This was a retrospective analysis of 29 patients (12 male, 57 ± 13 years) who underwent PET/CT and subsequently PET/MRI at the same day. Two readers evaluated independently four PET/MRI setups: (I) PET + T2 Half Fourier Acquisition Single Shot Turbo Spin Echo (T2 HASTE), (II) PET + T2 HASTE + T2-weighted spin-echo sequence (T2 TSE), III) PET + T2 HASTE + Diffusion Weighted Imaging (DWI) and (IV) PET + T2 HASTE + T2 TSE + DWI. A consensus reading of PET/MRI and PET/CT including follow-up examinations served as the reference standard for lesion-based analysis. Lesion sizes were assessed.

RESULTS

Setup IV provided comparable overall detection rates as PET/CT in both readers: PET/MRI 91.5%/92.9% versus 89.7% in PET/CT. In liver and bone lesions (mean diameter: 1.9 and 1.5 cm), PET/MRI was equal or superior to PET/CT: 98%/98% versus 85% in PET/CT; 100%/95% versus 100% in PET/CT, but inferior in pancreatic lesions, small bowel lesions and lymph node metastases (mean diameter: 1.3, 0.5 and 1.8 cm).

CONCLUSION

A non-enhanced MR protocol comprising T2 HASTE, T2 TSE and DWI for SSR-PET/MRI seems to provide comparable effectiveness in lesions detection as multiphase contrast-enhanced PET/CT. It might, therefore, serve as valid alternative, e.g., for follow-up examinations in patients with unresectable NET and kidney failure.

Clinical outcome and long-term survival of 150 consecutive patients with pancreatic neuroendocrine tumors: A comprehensive analysis by the World Health Organization 2010 grading classification

BACKGROUND AND OBJECTIVE

The World Health Organization (WHO) has revised its grading system for pancreatic neuroendocrine tumors (PNETs) in 2010 into three main group, which has not been widely and comprehensively evaluated. We aimed to validate the clinical valve of this system associated with the clinical outcome and long-term survival when applied to PNETs, which were rare and heterogeneous.

METHODS

We retrospectively collected and analyzed the data of 150 consecutive patients with PNETs who underwent a resection.

RESULTS

Sixty-four males and 86 females with PNETs were enrolled in our study. The clinical stage from I to IV by European Neuroendocrine Tumor Society were respectively defined in 53, 60, 19 and 18 patients. Seventy-two patients were pathologically diagnosed as neuroendocrine tumor G1 (NET G1), 48 as neuroendocrine tumor G2 (NET G2) and 30 as neuroendocrine carcinoma G3 (NEC G3). Patients with a radical resection obtained a notably higher overall survival (OS) than that of patients who underwent a palliative surgery (P=0.001). The 5-year OS of patients with NET G1 was significantly higher than that of patients with NET G2 (P=0.015) and NEC G3 (P<0.001); the comparison of OS for patients with NET G2 and NEC G3 was also statistically significant (P=0.005). In both univariate and multivariate analysis, clinical staging by ENETS (stage I and II vs. stage III and IV), resection (radical vs. palliative) and WHO 2010 grading classification (NET G1 and G2 vs. NEC G3) were validated to be independent predictors for the survivals of PNETs.

CONCLUSION

The newly-updated WHO 2010 grading classification was prognostic for the OS of PNETs and could be widely adopted in clinical practice.

Multilayered heterogeneity as an intrinsic hallmark of neuroendocrine tumors

Neuroendocrine tumors (NETs) comprise a complex and highly heterogeneous group of neoplasms that can arise all over the body, originating from neuroendocrine cells. NETs are characterized by a general lack of symptoms until they are in advanced phase, and early biomarkers are not as available and useful as required. Heterogeneity is an intrinsic, pivotal feature of NETs that derives from diverse causes and ultimately shapes tumor fate. The different layers that conform NET heterogeneity include a wide range of distinct characteristics, from the mere location of the tumor to its clinical and functional features, and from its cellular properties, to the core signaling and (epi)genetic components defining the molecular signature of the tumor. The importance of this heterogeneity resides in that it translates into a high variability among tumors and, hence, patients, which hinders a more precise diagnosis and prognosis and more efficacious treatment of these diseases. In this review, we highlight the significance of this heterogeneity as an intrinsic hallmark of NETs, its repercussion on clinical approaches and tumor management, and some of the possible factors associated to such heterogeneity, including epigenetic and genetic elements, post-transcriptional regulation, or splicing alterations. Notwithstanding, heterogeneity can also represent a valuable and actionable feature, towards improving medical approaches based on personalized medicine. We conclude that NETs can no longer be viewed as a single disease entity and that their diagnosis, prognosis and treatment must reflect and incorporate this heterogeneity.

Prognostic factors and survival after surgical resection of pancreatic neuroendocrine tumor with validation of established and modified staging systems

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) display wide heterogeneity with highly variable prognosis. This study aimed to identify variables related to survival after surgical resection of PNET.

METHODS

A total of 143 patients were identified from a prospectively maintained database. Patient characteristics were analyzed and prognostic factors for overall survival and progression-free survival were evaluated. The WHO, ENETS and AJCC scoring systems were applied to the cohort, and their ability to predict patient outcomes were compared.

RESULTS

Multivariate analysis found that female gender, lymph node metastases and increasing WHO 2010 grade to be independently associated with reduced overall survival (P < 0.05). Patients requiring multi-visceral resection or debulking surgery found to be associated with shortest survival. ROC analysis found the ENETS and AJCC scoring systems to be similarly predictive of 5-year overall survival. Modified Ki67 significantly improved its accuracy in predicting 5-year overall survival (AUROC: 0.699 vs 0.605; P < 0.01).

CONCLUSIONS

Multi-visceral or debulking surgery is associated with poor outcomes. There seems to be no significant difference between enucleation and anatomical segmental resection. Available scoring systems have reasonable accuracy in stratifying disease severity, with no system identified as being superior. Prognostic stratification with modified grading systems needs further validation before applied in clinical practice.

RSUME is implicated in tumorigenesis and metastasis of pancreatic neuroendocrine tumors

The factors triggering pancreatic neuroendocrine tumor (PanNET) progression are largely unknown. Here we investigated the role and mechanisms of the sumoylation enhancing protein RSUME in PanNET tumorigenesis. Immunohistochemical studies showed that RSUME is strongly expressed in normal human pancreas, in particular in β-cells. RSUME expression is reduced in insulinomas and is nearly absent in other types of PanNETs suggesting a role in PanNET tumorigenesis. In human pancreatic neuroendocrine BON1 cells, RSUME stimulates hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor-A (VEGF-A), which are key components of tumor neovascularisation. In contrast, RSUME suppresses nuclear factor-κB (NF-κB) and its target interleukin-8 (IL-8). Correspondingly, PanNET cells with RSUME knockdown showed decreased HIF-1α activity and increased NF-κB and IL-8 production leading to a moderate reduction of VEGF-A release as reduced HIF-1α/VEGF-A production is partly compensated by NF-κB/IL-8-induced VEGF-A. Notably, RSUME stabilizes the tumor suppressor PTEN, which is frequently lost in PanNETs and whose absence is associated with metastasis formation. In vivo orthotopic transplantation of PanNET cells with or without RSUME expression into nude mice showed that PanNETs without RSUME have reduced PTEN expression, grow faster and form multiple liver metastases. In sum, RSUME differentially regulates key components of PanNET formation suggesting that the observed loss of RSUME in advanced PanNETs is critically involved in PanNET tumorigenesis, particularly in metastasis formation.

Characterization of pancreatic glucagon-producing tumors and pituitary gland tumors in transgenic mice overexpressing MYCN in hGFAP-positive cells

Amplification or overexpression of MYCN is involved in development and maintenance of multiple malignancies. A subset of these tumors originates from neural precursors, including the most aggressive forms of the childhood tumors, neuroblastoma and medulloblastoma. In order to model the spectrum of MYCN-driven neoplasms in mice, we transgenically overexpressed MYCN under the control of the human GFAP-promoter that, among other targets, drives expression in neural progenitor cells. However, LSL-MYCN;hGFAP-Cre double transgenic mice did neither develop neural crest tumors nor tumors of the central nervous system, but presented with neuroendocrine tumors of the pancreas and, less frequently, the pituitary gland. Pituitary tumors expressed chromogranin A and closely resembled human pituitary adenomas. Pancreatic tumors strongly produced and secreted glucagon, suggesting that they derived from glucagon- and GFAP-positive islet cells. Interestingly, 3 out of 9 human pancreatic neuroendocrine tumors expressed MYCN, supporting the similarity of the mouse tumors to the human system. Serial transplantations of mouse tumor cells into immunocompromised mice confirmed their fully transformed phenotype. MYCN-directed treatment by AuroraA- or Brd4-inhibitors resulted in significantly decreased cell proliferation in vitro and reduced tumor growth in vivo. In summary, we provide a novel mouse model for neuroendocrine tumors of the pancreas and pituitary gland that is dependent on MYCN expression and that may help to evaluate MYCN-directed therapies.

[Surgical management of non-functioning pancreatic neuroendocrine tumors]

AIM

To analyze immediate and long-term results of surgical treatment of patients with non-functioning pancreatic neuroendocrine tumors (pNETs).

MATERIAL AND METHODS

Outcomes in 21 patients with non-functioning pNETs were retrospectively analyzed.

RESULTS

Long-term results were followed-up in 18 (85%) cases, median follow-up was 39 months. Postoperative mortality was 4.7%. The incidence of postoperative complications Clavien-Dindo degree IIIA and over was 20.8%, overall 5-year survival - 89%, desease-free 5-year survival - 78%.

CONCLUSION

At present time surgical intervention remains the only radical method of non-functioning pNETs management. Threshold tumor dimension should be 15 mm that determines surgical intervention or active surveillance. From an oncological point of view tumor enucleation is permissible only in case of small dimensions (up to 2 cm) and full confidence in low degree of malignancy. Lymphadenectomy should be performed in all cases in standard fashion because lymph node involvement is reliably poor prognostic sign.

Hepatic neuroendocrine tumour: Apparent diffusion coefficient as a potential marker of prognosis associated with tumour grade and overall survival

OBJECTIVES

To evaluate the correlation between grade of hepatic neuroendocrine tumours (NETs) according to the 2010 World Health Organization (WHO) classification and the apparent diffusion coefficient (ADC) and to assess whether ADC value can predict overall survival (OS) after diagnosis of hepatic NETs.

METHODS

The study included 63 patients who underwent magnetic resonance (MR) imaging with diffusion-weighted images for the evaluation of hepatic NETs. The correlation between qualitative and quantitative MR imaging findings, including ADC values, and WHO classifications was assessed. The association between ADC value and OS was analyzed.

RESULTS

The ADC values and WHO classification of hepatic NETs were moderately negatively correlated in a statistically significant manner (ρ = -0.57, p < 0.001). The OS rates were significantly different according to the ADC value (low ADC vs. high ADC, p = 0.006) as well as WHO classifications (G1+ G2 vs. G3, p = 0.038). However, multivariate analysis revealed that the only independent predictor for OS was a low ADC value (hazard ratio: 3.37, p = 0.010).

CONCLUSION

There was a significant correlation between the ADC value of hepatic NETs and the WHO tumour grade. Additionally, the ADC value of a hepatic NET might be more accurate than the current WHO tumour grade for predicting OS.

KEY POINTS

• ADC values of hepatic NET and WHO tumour grade were negatively correlated. • Lower ADC values of hepatic NET were significantly correlated with worse OS. • ADC value might be more accurate than WHO grade for predicting OS.

The efficacy of chemotherapy and operation in patients with colorectal neuroendocrine carcinoma

BACKGROUND

Colorectal neuroendocrine carcinoma (CRNEC) is a rare type of malignancy and is quite aggressive with dismal prognosis. Neither large-scale retrospective studies nor prospective studies have been performed to evaluate the prognostic value of adjuvant chemotherapy in patients with CRNEC.

METHODS

Using the Surveillance, Epidemiology, and End Results-Medicare database, 318 elderly patients who were diagnosed with high-grade colorectal neuroendocrine tumors were included. The survival benefit was evaluated using a Cox proportional hazards model and propensity score-matched techniques.

RESULTS

Among patients with stage I-III CRNEC, there was also no significant difference in cancer-specific survival (CSS) (P = 0.898) or overall survival (OS) (P = 0.539) between the 5-fluorouracil (5-FU) and the no chemotherapy groups. Meanwhile, the etoposide + platinum (EP) regimen showed no improved survival in patients with stage I-III CRNEC compared with the no chemotherapy group. For stage IV CRNEC, there was no significant difference between operation group and no operation group in CSS (P = 0.317) or OS (P = 0.385). Both 5-FU and EP regimens improved the CSS (for 5-FU, hazard ratio [HR] = 0.257, 95% confidence interval [CI] = 0.134-0.491, P < 0.001; for EP, HR = 0.348, 95% CI = 0.192-0.631, P = 0.001) and OS (for 5-FU, HR = 0.274, 95% CI = 0.149-0.502, P < 0.001; for EP, HR = 0.345, 95% CI = 0.194-0.612, P < 0.001) of patients in stage IV CRNEC.

CONCLUSIONS

Our findings demonstrated that neither the 5-FU based nor EP chemotherapy regimens improved the CSS or OS for patients with stage I-III CRNEC. And for stage IV CRNEC, chemotherapy is an independent prognostic factor for CSS and OS, while operation could not improve the CSS or OS for patients with stage IV CRNEC.

Insulinoma presenting with post-prandial hypoglycaemia following fundoplication

Insulinomas are rare neuroendocrine tumours that classically present with fasting hypoglycaemia. This case report discusses an uncommon and challenging case of insulinoma soon after upper gastrointestinal surgery. A 63-year-old man presented with 6 months of post-prandial hypoglycaemia beginning after a laparoscopic revision of Toupet fundoplication. Hyperinsulinaemic hypoglycaemia was confirmed during a spontaneous episode and in a mixed-meal test. Localisation studies including magnetic resonance imaging (MRI), endoscopic ultrasound (EUS) and gallium dotatate positron emission tomography (⁶⁸Ga Dotatate PET) were consistent with a small insulinoma in the mid-body of the pancreas. The lesion was excised and histopathology was confirmed a localised well-differentiated neuroendocrine pancreatic neoplasm. There have been no significant episodes of hypoglycaemia since. This case highlights several key points. Insulinoma should be sought in proven post-prandial hyperinsulinaemic hypoglycaemia - even in the absence of fasting hypoglycaemia. The use of nuclear imaging targeting somatostatin and GLP1 receptors has improved accuracy of localisation. Despite these advances, accurate surgical resection can remain challenging.

Learning points

Hypoglycaemia is defined by Whipple's triad and can be provoked by fasting or mixed-meal tests.Although uncommon, insulinomas can present with post-prandial hypoglycaemia.In hypoglycaemia following gastrointestinal surgery (i.e. bariatric surgery or less commonly Nissen fundoplication) dumping syndrome or non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) should be considered.Improved imaging techniques including MRI, endoscopic ultrasound and functional nuclear medicine scans aid localisation of insulinomas.Despite advances in imaging and surgical techniques, accurate resection of insulinomas remains challenging.

PPoma Review: Epidemiology, Aetiopathogenesis, Prognosis and Treatment

Generally, pancreatic polypeptide-secreting tumor of the distal pancreas (PPoma) is classified as a rare tumor, and may occur sporadically or be associated in families or with multiple endocrine neoplasia type 1 (NEM 1). It grows slowly, reaching large dimensions at the time of diagnosis and the symptomatology is fundamentally due to the mass effect, causing either non-specific abdominal pain or symptoms suggestive of obstruction of the pancreatic or biliary duct. Therefore, when detected, they are usually malignant, with metastases mainly in the liver. The combination of serum analysis of increased levels of chromogranin A and pancreatic polypeptide and pancreastatin is very useful with a sensitivity of up to 95%. However, in addition, scintigraphicexams with somatostatin analogues should be performed to better clarify the diagnosis. Surgical resection is the treatment of choice, despite surgical difficulty and because they are generally palliative due to the metastases. Surgeries for tumor volume reduction are also performed to relieve symptoms. Chemotherapy commonly uses streptozotocin and somatostatin analogues to treat residual disease. Unfortunately, the survival rates are still very low, less than 10%, and if metastases already exist, this percentage drops to 3%.

Targeted therapy of gastroenteropancreatic neuroendocrine tumours: preclinical strategies and future targets

Molecular targeted therapy of advanced neuroendocrine tumours (NETs) of the gastroenteropancreatic (GEP) system currently encompasses approved therapy with the mammalian target of rapamycin (mTOR) inhibitor everolimus and the multi-tyrosinkinase inhibitor sunitinib. However, clinical efficacy of these treatment strategies is limited by low objective response rates and limited progression-free survival due to tumour resistance. Further novel strategies for molecular targeted therapy of NETs of the GEP system are needed. This paper reviews preclinical research models and signalling pathways in NETs of the GEP system. Preclinical and early clinical data on putative novel targets for molecular targeted therapy of NETs of the GEP system are discussed, including PI3K, Akt, mTORC1/mTORC2, GSK3, c-Met, Ras-Raf-MEK-ERK, embryogenic pathways (Hedgehog, Notch, Wnt/beta-catenin, TGF-beta signalling and SMAD proteins), tumour suppressors and cell cycle regulators (p53, cyclin-dependent kinases (CDKs) CDK4/6, CDK inhibitor p27, retinoblastoma protein (Rb)), heat shock protein HSP90, Aurora kinase, Src kinase family, focal adhesion kinase and epigenetic modulation by histone deacetylase inhibitors.

Diffuse Pancreatic Neuroendocrine Tumor: A Rare Presentation

Diffuse involvement of the pancreas in neuroendocrine tumor is a rare presentation, and its appearance on In-111 pentetreotide scan has not been reported earlier in the literature. We present the whole body images from In-111 pentetreotide scan, contrast-enhanced computed tomography images, and histopathology correlation.

Health-Related Quality of Life in Patients with Small Intestine Neuroendocrine Tumors

BACKGROUND

The prevalence of small intestine neuroendocrine tumors (SI-NETs) is increasing. Disease progression is often slow and treatment options and long-term survival rates have improved, but little is known about health-related quality of life (HRQoL) in these patients.

OBJECTIVE

To assess HRQoL and its predictors in SI-NET patients receiving contemporary treatments.

METHODS

We measured HRQoL with 15D and SF-36 questionnaires in 134 SI-NET patients and compared the 15D results to those of an age- and gender-standardized sample of the general population (n = 1,153). In the patients, we studied the impact of treatments, Ki-67, liver metastases, circulating tumor markers, comorbidities, and/or socioeconomic factors on HRQoL with linear regression analysis.

RESULTS

The mean disease duration of the patients was 81 (4-468) months, 91% had metastatic disease, and 79% received somatostatin analog treatment. Hepatic tumor load was 0% in 44.8%, < 10-25% in 44.0%, and > 25% in 11.2%, respectively. Mean fP-CgA and S-5HIAA concentrations were 15 (1.3-250) and 344 (24-7,470) nmol/L, respectively. Overall, HRQoL was significantly impaired in patients compared to controls (15D score 0.864 ± 0.105 vs. 0.905 ± 0.028, p < 0.001). SI-NET patients scored worse on 9 of 15 dimensions: sleep, excretion (i.e., bladder and bowel function), depression, distress, vitality, sexual activity (p < 0.001), breathing, usual activities, and discomfort and symptoms (p < 0.01-0.05). SF-36 scores were impaired and highly correlated with 15D scores (p < 0.001). HRQoL was impaired in patients with (n = 85) compared to patients without (n = 49) impaired excretion (0.828 vs. 0.933, p < 0.001). In the patient group, number of medications predicted impaired HRQoL.

CONCLUSIONS

Despite contemporary treatments, SI-NET patients have severely impaired HRQoL, including diarrhea, sleep, depression, vitality, and sexual activity.

Clinicopathological features of gastroenteropancreatic neuroendocrine tumors: A retrospective evaluation of 42 cases

Objective

Neuroendocrine tumors arise from neuroendocrine cells in any part of the body; approximately two thirds of these tumors are located in the gastrointestinal tract and pancreas. Although gastroenteropancreatic neuroendocrine tumors are known as rare neoplasms, their prevalence has recently increased due to advanced diagnostic methods and increased awareness of the disorder. In the present study, we aimed to review patients who were treated and followed up for gastroenteropancreatic neuroendocrine tumors at our clinic in terms of clinical picture, pathological findings, and prognosis.

Material and Methods

Data from 42 patients diagnosed with gastroenteropancreatic neuroendocrine tumors who were treated and followed up at our Training and Research Hospital from August 2011 to December 2015 were retrospectively evaluated.

Results

A total of 42 patients aged 17-81 years (mean age 46.9 years) were enrolled in the study. The most common symptom was abdominal pain, which was seen in 31 (73.8%) patients. gastroenteropancreatic neuroendocrine tumors were detected in the stomach (n=5, 35.7%), appendix (n=11, 26.2%), rectum (n=6, 14.3%), pancreas (n=4, 9.5%), ileum and colon (n=2, 4.8%), and duodenum and jejunum (n=1, 2.4%). Local excision was performed in seven (16.7%) patients. Nine (21.4%) patients underwent gastric wedge resections, either by a laparoscopic procedure (n=3) or by open surgery (n=6). Total gastrectomy and laparoscopic subtotal gastrectomy were performed on three (7.1%) patients and two patients (4.8%), respectively. After the surgical procedures, the patients were followed up for a mean period of 36 months (15-57 months); the one-year and three-year survival rates were determined to be 100% and 97.6%, respectively.

Conclusion

Management of gastroenteropancreatic neuroendocrine tumors requires accumulation of knowledge and experience to establish a standardized approach. Therefore, we believe that collecting regular national data from these cases in every country will contribute to understanding the details of this entity worldwide.

Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

This review covers the diverse topic of neuroendocrine neoplasms (NENs), a relatively rare and heterogeneous tumor type, comprising ~2% of all malignancies, with a prevalence of <200,000 in the United States, which makes it an orphan disease (Basu et al., 2010).1 For functional purposes, NENs are divided into two groups on the basis of clinical behavior, histology, and proliferation rate: well differentiated (low grade to intermediate grade) neuroendocrine tumors and poorly differentiated (high grade) neuroendocrine carcinoma (Bosman et al., 2010)2; this histological categorization/dichotomization is highly clinically relevant with respect to impact on treatment and prognosis even though it is not absolute since a subset of tumors with a low-grade appearance behaves similarly to high-grade lesions. Given the relative dearth of evidenced-based literature about this orphan disease as a whole (Modlin et al., 2008),3 since the focus of most articles is on particular anatomic subtypes of NENs (i.e., gastroenteropancreatic or pulmonary), the purpose of this review is to summarize the presentation, pathophysiology, staging, current standard of care treatments, and active areas of current research.

Ki67 labeling index: assessment and prognostic role in gastroenteropancreatic neuroendocrine neoplasms

In 1983, a monoclonal antibody, Ki67, was generated, that labeled the nuclei of proliferating non-neoplastic and neoplastic cells. The name Ki67 derived from the city of Kiel (Ki) where the antibody was produced in the university department of pathology and refers to the number of the original clone (67). Systematic assessment of the proliferative activity of tumors using Ki67 started in the 1990s, when Ki67, which only worked on frozen tissue, was complemented by the antibody MIB-1 that also worked in formalin-fixed tissues. Pancreatic neuroendocrine neoplasms (PanNENs) were the first endocrine tumors whose proliferative activity was assessed with Ki67. This approach was so successful that Ki67 was included as prognostic marker in the 2000 and 2004 WHO classifications of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). In 2010, the WHO classification of GEP-NENs introduced a three-tiered grading, originally proposed by ENETS in 2006 that was mainly based on the Ki67 index. As it has subsequently been shown that the Ki67 index is the most reliable factor in the prognostic evaluation of GEP-NENs, especially of PanNENs, the 2017 WHO classification of PanNENs requires its use and strongly recommends exact assessment of the proportion Ki67-labeled cells as basis for the calculation of the Ki67 index. Problems in assessing the Ki67 index include intertumoral and intratumoral staining heterogeneity and counting methods. Despite such problems, the Ki67 index has emerged as indispensable for the prognostic and therapeutic stratification of the majority of GEP-NENs and can barely be replaced by counting mitoses. In future, however, it can be anticipated that the Ki67 cut-offs experience refinement in relation to the type of tumor, its location, and its response to therapy. It is also possible that the prognostic risk of an individual tumor is calculated for each Ki67 unit and not for an "a priori" fixed Ki67 class.

Trends in diagnosis of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in India: A report of multicenter data from a web-based registry

INTRODUCTION

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors. We report data of 407 GEP-NET cases from a neuroendocrine tumor (NET) registry in India.

METHODS

The AP-NET registry is an open-label, multicenter, longitudinal observational registry of patients with GEP-NETs in which six tertiary care oncology centers contributed data. Data was prospectively entered in a dedicated computerized database and was reviewed retrospectively. The patients were divided into three cohorts-those diagnosed from 2001 to 2005, from 2006 to 2010, and from 2011 to 2016.

RESULTS

Of the 407 cases registered, 37 were in Cohort I, 136 in Cohort II, and 234 in Cohort III. Majority were symptomatic with only 98 patients (24.0%) asymptomatic. The most common presentation of non-functional tumors was abdominal pain (42.4%), while functional tumors presented most commonly with carcinoid syndrome. Use of DOTA-PET, introduced in 2011, has increased evaluation in 33.3% patients in Cohort III. The most common primary site was pancreas in all three cohorts. Male preponderance (58.3%) was seen. Histopathological grading was obtained in 230 (56.5%) patients-118 (29%) Grade I, 74 (18.2%) Grade II, and 36 (8.8%) Grade III NET.

CONCLUSION

This report highlights changing trends in the diagnosis and reporting of NETs over the last 15 years.

Multimodality Imaging Findings in Carcinoid Tumors: A Head-to-Toe Spectrum

Carcinoid tumors are a rare biologically heterogeneous group of neuroendocrine tumors with a spectrum ranging from benign indolent to aggressive metastatic tumors. They belong to the category of amine precursor uptake and decarboxylase tumors, or apudomas. The most common sites for primary locations are the gastrointestinal and respiratory tracts; however, any organ can be involved. The clinical presentation depends on location, aggressiveness, production of biologically active amines and peptides, paraneoplastic syndromes, and tendency for metastasis. Their reported age-adjusted incidence has increased in recent years, partly due to improved detection at radiologic imaging and endoscopy. Not a ll neuroendocrine cell tumors are carcinoids. Numerous systems have been proposed regarding their nomenclature and classification. Cross-sectional and functional imaging plays an important role in diagnosis, lesion characterization, and staging. Awareness of nomenclature, classification, common sites of involvement, and imaging presentation are pivotal for making the diagnosis. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of carcinoid tumors involving various organs of the body is important for diagnosis and patient management. ^©RSNA, 2017.

Theranostics in nuclear medicine practice

The importance of personalized medicine has been growing, mainly due to a more urgent need to avoid unnecessary and expensive treatments. In nuclear medicine, the theranostic approach is an established tool for specific molecular targeting, both for diagnostics and therapy. The visualization of potential targets can help predict if a patient will benefit from a particular treatment. Thanks to the quick development of radiopharmaceuticals and diagnostic techniques, the use of theranostic agents has been continually increasing. In this article, important milestones of nuclear therapies and diagnostics in the context of theranostics are highlighted. It begins with a well-known radioiodine therapy in patients with thyroid cancer and then progresses through various approaches for the treatment of advanced cancer with targeted therapies. The aim of this review was to provide a summary of background knowledge and current applications, and to identify the advantages of targeted therapies and imaging in nuclear medicine practices.

A simple morphological classification to estimate the malignant potential of pancreatic neuroendocrine tumors

BACKGROUND

A novel morphological classification using resected specimens predicted malignant potential and prognosis in patients with pancreatic neuroendocrine tumors (P-NETs). The aim of this study was to examine the predictive ability of morphological diagnoses made using non-invasive multi-detector computed tomography (MDCT) in P-NETs.

METHODS

Between 2002 and 2015, 154 patients were diagnosed with P-NETs at the Tokyo Medical and Dental University, and 82 patients who underwent surgical treatment were enrolled. The primary tumors were classified by MDCT into three types: Type I, simple nodular tumor; Type II, simple nodular tumor with extra-nodular growth; and Type III, confluent multinodular tumor. Patients were stratified by 15 clinical specialists according to classification and without any other clinical or pathological information. Clinicopathological features and patient survival were reviewed retrospectively.

RESULTS

The mean observation time was 1004 days. Forty-six, 22, and 14 patients had Type I, II, and III tumors, respectively. Morphological classification was significantly correlated with advanced features such as tumor size, Ki-67 index, and synchronous liver metastasis (p < 0.001 for all). There were significant differences between all three tumor types as judged by ENETS TNM classification (p < 0.001), AJCC TNM classification (p = 0.046), WHO 2004 classification (p < 0.001), and WHO 2010 classification (p < 0.001). Five-year progression-free survival (PFS) rates for patients with Type I, II, and III tumors were 97, 43, and 31%, respectively (I vs. II, p < 0.001; I vs. III, p < 0.001; II vs. III, p = 0.017). Multivariate analysis revealed Type II/III tumors and synchronous liver metastasis to be independent risk factors for poor PFS.

CONCLUSION

A novel simple morphological classification system would predict Type II and III tumors that may have higher malignant potential than Type I tumors.

A nation-wide retrospective epidemiological study of gastroenteropancreatic neuroendocrine neoplasms in china

BACKGROUND

Representative data on the gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) in Asian patients is rare, especially in China. This study aims to create a GEP-NENs profile of Chinese patients.

METHODS

This was a hospital-based, nation-wide, and multi-center 10-year (2001-2010) retrospective study which collected GEP-NEN patients' information in tertiary referral hospitals. All 2010 inpatient GEP-NEN cases with confirmed pathology in the selected hospitals were included. The primary GEP-NEN sites were measured and the epidemiological and clinical information of each tumor site were compared.

RESULTS

The most common primary sites for GEP-NEN were the pancreas (31.5%) and rectum (29.6%), followed by the cardia (11.6%) and body (15.4%) of stomach. Small intestinal and colonic NENs took up a relatively small proportion of all patients. Pancreatic and rectal NENs, rather than cardiac and gastric body NENs, tended to be found in younger (P<0.001), female (P<0.001), urban (P<0.001) residents with a higher education level (P=0.032) and were also diagnosed at earlier stage (P<0.001) and lower grade (P<0.001). Surgery remained the primary treatment method in all groups.

CONCLUSIONS

More studies on the commonality and heterogeneity of GEP-NENs are warranted to improve diagnosis efficiencies and treatment outcomes.

Medical Therapy of Gastrointestinal Neuroendocrine Tumors

Intestinal neuroendocrine tumors (NETs) constitute a heterogeneous group with duodenal, small intestinal, colonic and rectal NETs. They constitute more than half of all NETs, with the highest frequencies in the rectum, small intestine, and colon. The tumor biology varies with the location of the primary tumor as well as with the grade and staging of the tumor. Small intestinal NETs usually present low proliferation and are treated in the first line with somatostatin analogs according to current guidelines. If progression occurs, one can add interferon alpha or change the treatment to everolimus. Peptide receptor radionuclide therapy (PRRT) with Lutetium¹⁷⁷-DOTATATE can be an option in the future after registration of the compound. Rectal tumors are usually small when they metastasize; they can be treated with somatostatin analogs but more so with PRRT, while another option is of course everolimus. Colonic NETs are more aggressive than the rest of intestinal NETs and will be treated with everolimus, sometimes in combination with somatostatin analogs based on positive scintigraphy. Another option is a cytotoxic agent such as streptozotocin plus 5-fluorouracil (5-FU) or temozolomide plus capecitabine. The most aggressive tumors, i.e. neuroendocrine carcinoma G3, are treated with a platin-based therapy plus etoposide; if they present with a lower proliferation, i.e. <50%, temozolomide plus capecitabine plus bevacizumab can also be attempted. Duodenal NETs are mostly treated similar to pancreatic NETs, either with cytotoxic agents, streptozotocin plus 5-FU, or temozolomide plus capecitabine, or with targeted agents such as everolimus.

Imaging of Neuroendocrine Tumors: Indications, Interpretations, Limits, and Pitfalls

Imaging is critical in the diagnosis, prognosis, and management of neuroendocrine tumors (NETs). NETs share common imaging features, but each type exhibits unique features. Computed tomography scans or MRI of the abdomen is used to assess tumor burden routinely. Functional imaging with octreotide scan or gallium-68 somatostatin analog PET is used selectively to confirm diagnosis and guide therapy. Clinicians and radiologists should be familiar with the indications and interpretations of imaging modalities. Novel functional imaging modalities likely will be developed to detect small NETs, predict prognosis, guide therapeutic choices, and design novel therapies.