Influence of Lymphatic, Microvascular and Perineural Invasion on Oncological Outcome in Patients with Neuroendocrine Tumors of the Small Intestine

For the histopathological work-up of resected neuroendocrine tumors of the small intestine (siNET), the determination of lymphatic (LI), microvascular (VI) and perineural (PnI) invasion is recommended. Their association with poorer prognosis has already been demonstrated in many tumor entities. However, the influence of LI, VI and PnI in siNET has not been sufficiently described yet. A retrospective analysis of all patients treated for siNET at the ENETS Center of Excellence Charité-Universitätsmedizin Berlin, from 2010 to 2020 was performed (n = 510). Patients who did not undergo primary resection or had G3 tumors were excluded. In the entire cohort (n = 161), patients with LI, VI and PnI status had more distant metastases (48.0% vs. 71.4%, p = 0.005; 47.1% vs. 84.4%, p < 0.001; 34.2% vs. 84.7%, p < 0.001) and had lower rates of curative surgery (58.0% vs. 21.0%, p < 0.001; 48.3% vs. 16.7%, p < 0.001; 68.4% vs. 14.3%, p < 0.001). Progression-free survival was significantly reduced in patients with LI, VI or PnI compared to patients without. This was also demonstrated in patients who underwent curative surgery. Lymphatic, vascular and perineural invasion were associated with disease progression and recurrence in patients with siNET, and these should therefore be included in postoperative treatment considerations.

Plasma Markers for Therapy Response Monitoring in Patients with Neuroendocrine Tumors Undergoing Peptide Receptor Radionuclide Therapy

BACKGROUND

Pretherapeutic chromogranin A, alkaline phosphatase (ALP), or De Ritis ratio (aspartate aminotransferase/alanine aminotransferase) are prognostic factors in patients with metastatic neuroendocrine tumors (NET) undergoing peptide receptor radionuclide therapy (PRRT). However, their value for intratherapeutic monitoring remains unclear. We evaluated if changes in plasma markers during PRRT can help identify patients with unfavorable outcomes.

METHODS

A monocentric retrospective analysis of 141 patients with NET undergoing PRRT with [177Lu]Lu-DOTATOC was conducted. Changes in laboratory parameters were calculated by dividing the values determined immediately before each cycle of PRRT by the pretherapeutic value. Patients with low vs. high PFS were compared with the Wilcoxon rank-sum test.

RESULTS

Progression, relapse, or death after PRRT was observed in 103/141 patients. Patients with low PFS showed a significant relative ALP increase before the third (p = 0.014) and fourth (p = 0.039) cycles of PRRT. Kaplan-Meier analysis revealed a median PFS of 24.3 months (95% CI, 20.7-27.8 months) in patients with decreasing ALP values (Δ > 10%) during treatment, 12.5 months (95% CI, 9.2-15.8 months) in patients with increasing ALP values (Δ > 10%), and 17.7 months (95% CI, 13.6-21.8 months) with stable ALP values (Δ ± 10%).

CONCLUSIONS

Based on these exploratory data, a rise in plasma ALP might indicate disease progression and should be interpreted cautiously during therapy.

Osteopontin is a prognostic circulating biomarker in patients with neuroendocrine neoplasms

PURPOSE

Osteopontin (OPN), also called secreted phosphoprotein 1 (SPP1) is a matricellular glycoprotein whose expression is elevated in various types of cancer and which has been shown to be involved in tumorigenesis and metastasis in many malignancies. Its role in neuroendocrine neoplasms (NEN) remains to be established. The aim of the study was to analyze plasma concentrations of OPN in patients with NEN and to explore its diagnostic and prognostic value as a clinical biomarker.

METHODS

OPN plasma concentrations were measured in a total of 38 patients with histologically proven NEN at three different time points during the course of disease and therapy (at the start of the study, after 3 and 12 months, respectively) as well as in healthy controls. Clinical and imaging data as well as concentrations of Chromogranin A (CgA) and Neuron Specific Enolase (NSE) were assessed.

RESULTS

OPN levels were significantly higher in patients with NEN compared to healthy controls. High-grade tumors (grade 3) showed the highest OPN levels. OPN levels were neither different between male and female patients nor between different primary tumor sites. OPN correlated significantly with corresponding NSE levels, while there was no correlation with Chromogranin A. High OPN levels above a cutoff value of 200 ng/ml at initial analysis predicted a worsened prognosis with significantly shorter progression-free survival of patients with NEN, which also held true within the subgroup of well-differentiated G1/G2 tumors.

CONCLUSION

Our data indicate that high baseline OPN levels in patients with NEN are predictive of an adverse outcome with shorter progression-free survival, even within the group of well differentiated G1/G2 tumors. Therefore, OPN may be used as a surrogate prognostic biomarker in patients with NEN.

Analyses of sex-based clinicopathological differences among patients with gastrointestinal neuroendocrine neoplasms in Europe

BACKGROUND

Previous studies have found variations in cancer types, tumor progression, and disease outcomes between men and women. However, there is limited knowledge of the effect of sex on gastrointestinal neuroendocrine neoplasms (GI-NENs).

METHODS

We identified 1354 patients with GI-NEN from the IQVIA's Oncology Dynamics database. Patients were derived from four European countries (Germany, France, the United Kingdom (UK), Spain). Clinical and tumor related characteristics including patients' age, tumor stage, tumor grading and differentiation, frequency and sites of metastases, as well as co-morbidities were analyzed as a function of patients´ sex.

RESULTS

Among the 1354 included patients, 626 were female and 728 were male. The median age was similar between both groups (w: 65.6 years, SD: 12.1 vs. m: 64.7 years; SD: 11.9; p = 0.452). UK was the country with the most patients, however, there was no differences in the sex ratio between the different countries. Among documented co-morbidities, asthma was more often diagnosed in women (7.7% vs. 3.7%), while COPD was more prevalent in men (12.1% vs. 5.8%). The ECOG performance states was comparable between females and males. Of note, the patients´ sex was not associated with tumor origin (e.g., pNET or siNET). Females were overrepresented among G1 tumors (22.4% vs. 16.8%), however, median proliferation rates according to Ki-67 were similar between both groups. In line, no differences in tumor stages was found and rates of metastases as well as the specific sites of metastases were similar between males and females. Finally, no differences in the applied tumor specific treatments between the both sexes became apparent.

CONCLUSION

Females were overrepresented among G1 tumors. No further sex-specific differences became apparent, highlighting that sex-related factors might play a rather subordinate role in the pathophysiology of GI-NENs. Such data may help to better understand the specific epidemiology of GI-NEN.

The Role of Alternative Lymph Node Classification Systems in Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NEN): Superiority of a LODDS Scheme Over N Category in Pancreatic NEN (pNEN)

Lymph node (LN) involvement in gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) has been reported to have prognostic and therapeutic implications. Numerous novel LN classifications exist; however, no comparison of their prognostic performance for GEP-NEN has been done yet. Using a nationwide cohort from the German Neuroendocrine Tumor (NET) Registry, the prognostic and discriminatory power of different LN ratio (LNR) and log odds of metastatic LN (LODDS) classifications were investigated using multivariate Cox regression and C-statistics in 671 patients with resected GEP-NEN. An increase in positive LN (pLN), LNR, and LODDS was associated with advanced tumor stages, distant metastases, and hormonal functionality. However, none of the alternative LN classifications studied showed discriminatory superiority in predicting prognosis over the currently used N category. Interestingly, in a subgroup analysis, one LODDS classification was identified that might be most appropriate for patients with pancreatic NEN (pNEN). On this basis, a nomogram was constructed to estimate the prognosis of pNEN patients after surgery. In conclusion, a more accurate classification of LN status may allow a more precise prediction of overall survival and provide the basis for individualized strategies for postoperative treatment and surveillance especially for patients with pNEN.

Prognostic differences in grading and metastatic lymph node pattern in patients with small bowel neuroendocrine tumors

PURPOSE

Neuroendocrine tumors of the small intestine (si-NET) describe a heterogenous group of neoplasms. Based on the Ki67 proliferation index si-NET are divided into G1 (Ki67 < 2%), G2 (Ki67 3-20%) and rarely G3 (Ki67 > 20%) tumors. However, few studies evaluate the impact of tumor grading on prognosis in si-NET. Moreover, si-NET can form distinct lymphatic spread patterns to the mesenteric root, aortocaval lymph nodes, and distant organs. This study aims to identify prognostic factors within the lymphatic spread patterns and grading.

METHODS

Demographic, pathological, and surgical data of 208 (90 male, 118 female) individuals with si-NETs treated at Charité University Medicine Berlin between 2010 and 2020 were analyzed retrospectively.

RESULTS

A total of 113 (54.5%) specimens were defined as G1 and 93 (44.7%) as G2 tumors. Interestingly, splitting the G2 group in two subgroups: G2 low (Ki67 3-9%) and G2 high (Ki67 10-20%), displayed significant differences in overall survival (OS) (p = 0.008) and progression free survival (PFS) (p = 0.004) between these subgroups. Remission after surgery was less often achieved in patients with higher Ki67 index (> 10%). Lymph node metastases (N +) were present in 174 (83.6%) patients. Patients with isolated locoregional disease showed better PFS and OS in comparison to patients with additional aortocaval and distant lymph node metastases.

CONCLUSION

Lymphatic spread pattern influences patient outcome. In G2 tumors, low and high grading shows heterogenous outcome in OS and PFS. Differentiation within this group might impact follow-up, adjuvant treatment, and surgical strategy.

Proposal of early CT morphological criteria for response of liver metastases to systemic treatments in gastroenteropancreatic neuroendocrine tumors: Alternatives to RECIST

RECIST 1.1 criteria are commonly used with computed tomography (CT) to evaluate the efficacy of systemic treatments in patients with neuroendocrine tumors (NETs) and liver metastases (LMs), but their relevance is questioned in this setting. We aimed to explore alternative criteria using different numbers of measured LMs and thresholds of size and density variation. We retrospectively studied patients with advanced pancreatic or small intestine NETs with LMs, treated with systemic treatment in the first-and/or second-line, without early progression, in 14 European expert centers. We compared time to treatment failure (TTF) between responders and non-responders according to various criteria defined by 0%, 10%, 20% or 30% decrease in the sum of LM size, and/or by 10%, 15% or 20% decrease in LM density, measured on two, three or five LMs, on baseline (≤1 month before treatment initiation) and first revaluation (≤6 months) contrast-enhanced CT scans. Multivariable Cox proportional hazard models were performed to adjust the association between response criteria and TTF on prognostic factors. We included 129 systemic treatments (long-acting somatostatin analogs 41.9%, chemotherapy 26.4%, targeted therapies 31.8%), administered as first-line (53.5%) or second-line therapies (46.5%) in 91 patients. A decrease ≥10% in the size of three LMs was the response criterion that best predicted prolonged TTF, with significance at multivariable analysis (HR 1.90; 95% CI: 1.06-3.40; p = .03). Conversely, response defined by RECIST 1.1 did not predict prolonged TTF (p = .91), and neither did criteria based on changes in LM density. A ≥10% decrease in size of three LMs could be a more clinically relevant criterion than the current 30% threshold utilized by RECIST 1.1 for the evaluation of treatment efficacy in patients with advanced NETs. Its implementation in clinical trials is mandatory for prospective validation. Criteria based on changes in LM density were not predictive of treatment efficacy. CLINICAL TRIAL REGISTRATION: Registered at CNIL-CERB, Assistance publique hopitaux de Paris as "E-NETNET-L-E-CT" July 2018. No number was assigned. Approved by the Medical Ethics Review Board of University Medical Center Groningen.

Intratumoral dendritic cells and T cells predict survival in gastroenteropancreatic neuroendocrine neoplasms

Clinical management of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) remains challenging. We recently introduced FMS-like tyrosine kinase 3 ligand (FLT3LG) as a possible biomarker for a proinflammatory tumor microenvironment. Here, we put a spotlight on the quantitative assessment of classical dendritic cells (cDC) and T cells in the context of FLT3LG mRNA levels in a retrospective study on NET G2/ G3 and NEC of pancreatic and gastric origin. Abundance of cDC and T cells and their relevant subpopulations were determined by immunofluorescent staining and correlated with FLT3LG mRNA levels as well as clinical outcome. Immune cell counts attested highly variable infiltration densities. Samples with presence of cDC or high numbers of T cells exhibited increased FLT3LG expression. Abundance of cDC, defined as HLA-DR+CD11c+ cells with CLEC9a (cDC1) or CD1c (cDC2), as well as CD3+ T cell and CTL (CD8+ CD3+) numbers correlated with FLT3LG mRNA levels and predicted disease-specific survival. Combining FLT3LG and T cell counts further improved this prediction. Therefore, tumor-infiltrating cDC and T cells are prognostic markers in NET G2/ G3 or NEC and FLT3LG mRNA may serve as a simple to use biomarker for a quantitative estimate of their abundance, mandating prospective evaluation in the context of immune-targeted therapies.

Distribution of gastrointestinal neuroendocrine tumors in Europe: results from a retrospective cross-sectional study

BACKGROUND

Gastrointestinal (non-pancreatic) neuroendocrine tumors (GI-NETs) represent a rare but increasingly common tumor entity. Prognosis and biological behavior of these tumors is extremely heterogenous and largely dependent on the specific tumor site, stage and differentiation. However, systematic data on the epidemiology of GI-NET, especially in terms of geographic distributions are missing.

METHODS

We used the Oncology Dynamics database (IQVIA) to identify a total of 1354 patients with GI-NET from four European countries (Germany, France, Spain, UK) and compared them with regard to major patient and tumor related characteristics including patients' age, sex, tumor stage, tumor grading and differentiation.

RESULTS

Out of the analyzed 1354 NET patients, 535 were found in the UK (39.5%), 289 in Germany (21.3%), 283 in Spain (20.9%) and 247 in France (18.2%). More patients were male than female (53.8% vs. 46.2%) with no significant differences between the analyzed countries. In contrast, the age distribution varied between the different countries, with the highest number of patients identified in the age groups of 61-70 years (31.0%) and 71-80 years (30.7%). The vast majority of patients showed a tumor origin in the small intestine, in German patients NET of the large intestine were slightly overrepresented and NET of the stomach underrepresented compared to all other countries. More than 80% of patients had stage IV disease at the time of diagnosis. Regarding tumor histology, most tumors showed a G2 tumor; interestingly, a G3 grading was found in 40.9% of patients in Germany (Ki-67 > 20%).

CONCLUSION

The distribution of important patient- and tumor-specific characteristics of neuroendocrine tumors shows regional differences in four major European countries. These data may help to better understand the specific epidemiology of GI-NET in Europe.

Surgical Approach to Liver Metastases in GEP-NET in a Tertiary Reference Center

Indications for liver resection in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NET) vary from liver resection with curative intent to tumor debulking or tissue sampling for histopathological characterization. With increasing expertise, the number of minimally invasive liver surgeries (MILS) in GEP-NET patients has increased. However, the influence on the oncological outcome has hardly been described. The clinicopathological data of patients who underwent liver resection for hepatic metastases of GEP-NET at the Department of Surgery, Charité—Universitätsmedizin Berlin, were analyzed. Propensity score matching (PSM) was performed to compare MILS with open liver surgery (OLS). In total, 22 patients underwent liver surgery with curative intent, and 30 debulking surgeries were analyzed. Disease-free survival (DFS) was longer than progression-free survival (PFS) (10 vs. 24 months), whereas overall survival (OS) did not differ significantly (p = 0.588). Thirty-nine (75%) liver resections were performed as OLS, and thirteen (25%) as MILS. After PSM, a shorter length of hospital stay was found for the MILS group (14 vs. 10 d, p = 0.034), while neither DFS/PFS nor OS differed significantly. Both curative intended and cytoreductive resection of hepatic GEP-NET metastases achieved excellent outcomes. MILS led to a reduced length of hospital, while preserving a good oncological outcome.

Hemicolectomy versus appendectomy for patients with appendiceal neuroendocrine tumours 1-2 cm in size: a retrospective, Europe-wide, pooled cohort study

BACKGROUND

Awareness of the potential global overtreatment of patients with appendiceal neuroendocrine tumours (NETs) of 1-2 cm in size by performing oncological resections is increasing, but the rarity of this tumour has impeded clear recommendations to date. We aimed to assess the malignant potential of appendiceal NETs of 1-2 cm in size in patients with or without right-sided hemicolectomy.

METHODS

In this retrospective cohort study, we pooled data from 40 hospitals in 15 European countries for patients of any age and Eastern Cooperative Oncology Group performance status with a histopathologically confirmed appendiceal NET of 1-2 cm in size who had a complete resection of the primary tumour between Jan 1, 2000, and Dec 31, 2010. Patients either had an appendectomy only or an appendectomy with oncological right-sided hemicolectomy or ileocecal resection. Predefined primary outcomes were the frequency of distant metastases and tumour-related mortality. Secondary outcomes included the frequency of regional lymph node metastases, the association between regional lymph node metastases and histopathological risk factors, and overall survival with or without right-sided hemicolectomy. Cox proportional hazards regression was used to estimate the relative all-cause mortality hazard associated with right-sided hemicolectomy compared with appendectomy alone. This study is registered with ClinicalTrials.gov, NCT03852693.

FINDINGS

282 patients with suspected appendiceal tumours were identified, of whom 278 with an appendiceal NET of 1-2 cm in size were included. 163 (59%) had an appendectomy and 115 (41%) had a right-sided hemicolectomy, 110 (40%) were men, 168 (60%) were women, and mean age at initial surgery was 36·0 years (SD 18·2). Median follow-up was 13·0 years (IQR 11·0-15·6). After centralised histopathological review, appendiceal NETs were classified as a possible or probable primary tumour in two (1%) of 278 patients with distant peritoneal metastases and in two (1%) 278 patients with distant metastases in the liver. All metastases were diagnosed synchronously with no tumour-related deaths during follow-up. Regional lymph node metastases were found in 22 (20%) of 112 patients with right-sided hemicolectomy with available data. On the basis of histopathological risk factors, we estimated that 12·8% (95% CI 6·5 -21·1) of patients undergoing appendectomy probably had residual regional lymph node metastases. Overall survival was similar between patients with appendectomy and right-sided hemicolectomy (adjusted hazard ratio 0·88 [95% CI 0·36-2·17]; p=0·71).

INTERPRETATION

This study provides evidence that right-sided hemicolectomy is not indicated after complete resection of an appendiceal NET of 1-2 cm in size by appendectomy, that regional lymph node metastases of appendiceal NETs are clinically irrelevant, and that an additional postoperative exclusion of metastases and histopathological evaluation of risk factors is not supported by the presented results. These findings should inform consensus best practice guidelines for this patient cohort.

FUNDING

Swiss Cancer Research foundation.

Spectral Computed Tomography-Derived Iodine Content and Tumor Response in the Follow-Up of Neuroendocrine Tumors-A Single-Center Experience

Spectral computed tomography (SCT) allows iodine content (IC) calculation for characterization of hypervascularized neoplasms and thus might help in the staging of neuroendocrine tumors (NETs). This single-center prospective study analyzed the association between SCT-derived IC and tumor response in the follow-up of metastasized NETs. Twenty-six patients with a median age of 70 years (range 51-85) with histologically proven NETs and a total of 78 lesions underwent SCT for staging. Because NETS are rare, no primary NET types were excluded. Lesions and intralesional hotspots were measured in virtual images and iodine maps. Tumor response was classified as progressive or nonprogressive at study endpoint. Generalized estimating equations served to estimate associations between IC and tumor response, additionally stratified by lesion location. Most commonly affected sites were the lymph nodes, liver, pancreas, and bones. Median time between SCT and endpoint was 64 weeks (range 5-260). Despite statistical imprecision in the estimate, patients with higher IC in lymphonodular metastases had lower odds for disease progression (adjusted OR = 0.21, 95% CI: 0.02-2.02). Opposite tendencies were observed in hepatic and pancreatic metastases in unadjusted analyses, which vanished after adjusting for therapy and primary tumor grade.

Clinical characteristics of 662 patients with pancreatic neuroendocrine tumors receiving antitumoral therapy

Pancreatic neuroendocrine neoplasia constitute an important subentity of the gastroenteropancreatic neuroendocrine neoplasms accounting for up to 15% of all neuroendocrine neoplasm. Prognosis and oncological behavior of pancreatic neuroendocrine tumors (pNETs) is extremely heterogenous and dependent on the specific tumor stage and differentiation. However, systematic data on the specific epidemiology of pNET are scarce. We identified 662 patients with pNET within the Oncology Dynamics database (IQVIA). Patients were derived from 4 European countries (Germany, France, UK, Spain), 3 Asian countries (Japan, China, South Korea) and 2 South American countries (Mexico and Brazil) and with regard to major patient and tumor related characteristics including patients' age, sex, tumor stage, tumor grading, and differentiation. The mean age of the study cohort was 62 years (SD 12 years) with 53.9.1% of all patients being male. The majority of patients had an Eastern co-operative of Oncology Group 1 performance status (63.3%). The most common Union international contre le cancer tumor stage was stage IV (85%) with liver metastases (89.0%) representing the most common site of extra-pancreatic tumor manifestation. The majority of all patients displayed well or moderate tumor differentiation (9.6% of patients had a Ki-67 expression below 2%. 67.6% of pNET patients had a Ki-67 expression between 2 and 20% and 22.8% of patients showed an expression above 20%). At time point of diagnoses, 93.1% of patients were classified as inoperable. Of note, 93.9 % of patients received systemic anti-tumoral therapy in palliative intention, while treatment was administered in 1.4 % of cases in neoadjuvant and in 4.7% of cases in in an adjuvant setting. Biological therapy was applied to 39.4% of patients, followed by targeted therapies (31.4%) and chemotherapy. Pancreatic neuroendocrine neoplasia are diagnosed in advanced tumor stages, globally. Systemic treatment was the most commonly used treatment modality. Such data may help to better understand the specific epidemiology of pNET worldwide.

Differenzierte Therapiestrategie bei Lebermetastasen gastro-entero-pankreatischer Neuroendokriner Neoplasien

Neuroendokrine Neoplasien (NEN) bilden eine heterogene Gruppe maligner Tumoren, die überwiegend dem gastro-entero-pankreatischen System (GEP) zuzuordnen sind. Hierbei sind Dünndarm und Pankreas die häufigsten Organe für Primärtumoren, die Leber stellt den dominanten Metastasierungsort dar. Da viele Patient*innen lange asymptomatisch bleiben, führen oftmals zufällig diagnostizierte Lebermetastasen oder ein Ileus zur Diagnose. Die einzige kurative Therapieoption stellt die komplette Entfernung von Primarius und Metastasen dar. Besonders im Falle der metastasierten Erkrankung sollten die vorhandenen Therapieoptionen immer im interdisziplinären Tumorboard mit Spezialisten*innen aus Gastroenterologie, (Leber-)Chirurgie, Radiologie, Nuklearmedizin, Radiotherapie, Pathologie und Endokrinologie evaluiert werden. Durch die Kombination der verschiedenen Therapieverfahren kann auch für Patient*innen mit fortgeschrittener Erkrankung eine jahrelange Prognose bei guter Lebensqualität erreicht werden. Wichtig für die Therapieentscheidung sind neben patientenindividuellen Faktoren der Differenzierungsgrad des Tumors, dessen hormonelle Sekretion, das Metastasierungsmuster und der Erkrankungsverlauf. Die Behandlung von Lebermetastasen umfasst neben den unterschiedlichen chirurgischen Strategien die lokal-ablativen radiologischen und nuklearmedizinischen Verfahren, die als Ergänzung zu den systemischen Therapien zur Verfügung stehen.

Treatment Approaches and Outcome of Patients with Neuroendocrine Neoplasia Grade 3 in German Real-World Clinical Practice

Simple Summary

Grade 3 neuroendocrine neoplasms (NEN G3) are a rare and heterogeneous subtype of NEN and include poorly differentiated neuroendocrine carcinomas and well-differentiated neuroendocrine tumors G3 (NET G3). Standard chemotherapy with platinum plus etoposide may not be appropriate for all subgroups, but more tailored approaches suffer from the lack of data. In our study, we provide real-world data from a large center-based cohort of the German NET Registry and hope to stimulate efforts to conduct clinical trials for well-defined entities.

Abstract

Background: Neuroendocrine neoplasia grade 3 (NEN G3) represents a rare and heterogeneous cancer type with a poor prognosis. The aim of our study was to analyze real-world data from the German NET Registry with a focus on therapeutic and prognostic aspects. Methods: NEN G3 patients were identified within the German NET Registry. Demographic data and data on treatments and outcomes were retrieved. Univariate analyses were performed using the Kaplan–Meier-method. Multivariate analysis was performed using a Cox proportional hazard model. Results: Of 445 included patients, 318 (71.5%) were diagnosed at stage IV. Well-differentiated morphology (NET G3) was described in 31.7%, 60% of cases were classified as neuroendocrine carcinoma (NEC), and the median Ki67 value was 50%. First-line treatment comprised chemotherapy in 43.8%, with differences in the choice of regimen with regard to NET or NEC, and surgery in 41.6% of patients. Median overall survival for the entire cohort was 31 months. Stage, performance status and Ki67 were significant prognostic factors in multivariate analysis. Conclusions: The survival data of our national registry compare favorably to population-based data, probably mainly because of a relatively low median Ki67 of 50%. Nevertheless, the best first- and second-line approaches for specific subgroups remain unclear, and an international effort to fill these gaps is needed.

Prognostic Value of the Largest Lesion Size for Progression-Free Survival in Patients with NET Undergoing Salvage PRRT with [177Lu]Lu-DOTATOC

Simple Summary

Peptide receptor radionuclide therapy (PRRT) using radionuclide-labeled somatostatin analogues is based on the overexpression of somatostatin receptors on neuroendocrine tumors and is shown to have a good safety profile and efficacy in different types of metastatic neuroendocrine tumors. As this therapy is usually not curative, most patients experience disease progression after initial PRRT. In these cases, retreatment with PRRT, also called salvage PRRT, can be a treatment option, but little is known about the efficacy and possible risk factors. In this retrospective study that included 32 patients, we found that the size of the largest lesion is a significant predictor of disease progression after salvage PRRT. This risk factor is easy to obtain and can help identify patients who may benefit from intensified follow-up strategies.

Abstract

(1) Background: retreatment with radionuclide-labeled somatostatin analogues following disease progression after initial treatment cycles is often referred to as salvage peptide receptor radionuclide therapy (salvage PRRT). Salvage PRRT is shown to have a favorable safety profile in patients with metastatic neuroendocrine tumors (NETs), but numerous questions about the efficacy and prognostic or predictive factors remain to be answered. The purpose of this study was to evaluate two parameters that have shown prognostic significance in progression-free survival (PFS) in initial PRRT treatment, namely the size of the largest lesion (LLS) and the De Ritis ratio (aspartate aminotransferase (AST)/alanine aminotransferase (ALT)), as prognostic factors in the context of salvage PRRT. In addition, the PFS after initial PRRT was evaluated as a predictor of the PFS following salvage PRRT. (2) Methods: retrospective, monocentric analysis in 32 patients with NETs (gastroenteropancreatic, 23; unknown primary, 7; kidney, 1; lung, 1) and progression after initial PRRT undergoing retreatment with [¹⁷⁷Lu]Lu-DOTATOC. The prognostic values of LLS, the De Ritis ratio, and PFS after initial treatment cycles regarding PFS following salvage PRRT were evaluated with univariable and multivariable Cox regression. PFS was defined as the time from treatment start until tumor progression according to RECIST 1.1 criteria, death from any cause or start of a new treatment due to progression of cancer-related symptoms (namely carcinoid syndrome). (3) Results: progression after salvage PRRT was observed in 29 of 32 patients with median PFS of 10.8 months (95% confidence interval (CI), 8.0–15.9 months). A higher LLS (hazard ratio (HR): 1.03; p = 0.002) and a higher De Ritis ratio (HR: 2.64; p = 0.047) were associated with shorter PFS after salvage PRRT in univariable Cox regression. PFS after initial PRRT was not associated with PFS following salvage PRRT. In multivariable Cox regression, only LLS remained a significant predictor. (4) Conclusions: the size of the largest lesion is easy to obtain and might help identify patients at risk of early disease progression after salvage PRRT. Validation is required.

Ramucirumab in combination with dacarbazine in patients with progressive well-differentiated metastatic pancreatic neuroendocrine tumors (RamuNET): study protocol for a multicenter single-arm trial

BACKGROUND

Cytotoxic chemotherapy combinations and targeted agents represent established treatment concepts in advanced pancreatic neuroendocrine tumors (PNETs). However, response rates, side effects and outcome data strongly vary among these therapeutic approaches. Head-to-head comparisons between chemo- and molecular therapies are missing and secondary resistances frequently occur. The RamuNET trial aims to identify the effectiveness of dual treatment with DTIC and ramucirumab in progressive advanced PNET patients.

METHODS

The RamuNET study is an investigator-initiated multicenter prospective single-arm trial to evaluate the efficacy of ramucirumab in combination with dacarbazine (DTIC) over a period of at least 6 months. Patients with progressive well-differentiated and metastatic pancreatic neuroendocrine tumors are eligible. The study aims to include 45 patients over a period of 24 months with a minimum follow-up of 24 months. The primary endpoint is disease control after 6 months. Secondary endpoints include progression-free survival, biochemical response, overall survival, quality of life and toxicity. Based on the hypothesis that 80% of the patients can achieve a disease control after 6 months, the sample size calculation follows an exact binomial single-stage design. H0: p < =p0 = 60% versus H1: p > =p1 = 80%, alpha = 0.05, beta = 0.1.

DISCUSSION

This study investigates a new therapeutic approach using the combination of cytotoxic and targeted antiangiogenic therapy in advanced PNET. If positive, this trial will be the basis for a randomized two-arm study to investigate the combination of ramucirumab and DTIC against other established therapies in PNET.

TRIAL REGISTRATION

EudraCT: 2017-001207-68 . Date of registration: 2018.01.03.

29 Elevated Flt3L predicts long-term survival in patients with high-grade gastroenteropancreatic neuroendocrine neoplasms

Background

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) are a rare and heterogeneous family of tumors arising from the disseminated neuroendocrine system of the gastrointestinal tract and pancreas. Clinical management of high-grade GEP-NEN is challenging due to disease heterogeneity, illustrating the need for reliable biomarkers facilitating patient stratification and guiding treatment decisions. FMS-like tyrosine kinase 3 ligand (Flt3L) is emerging as a prognostic or predictive surrogate marker of host tumoral immune response and might enable stratification of patients with otherwise comparable tumor features.

Methods

We used RNAseq data from human foregut-derived pancreatic and gastric GEP-NEN to evaluate Flt3L gene expression in tumor tissue. The data set (n=54) represented the full range of NEN grades and differentiation, and expression levels were compared to healthy control tissue as well. We also analyzed circulating Flt3L levels in serum samples of a separate cohort of G2/G3 GEP-NEN (n=59) an healthy controls (n=4). The study was approved by the local ethics committee at Charité Universitätsmedizin Berlin, Germany (ethical approval number EA1/229/17) and patient informed consent was obtained.

Results

We detected a prominent induction of Flt3L gene expression in individual G2 and G3 NEN, but not in G1 neuroendocrine tumors (NET). Flt3L mRNA expression levels in tumor tissue predicted disease related survival of patients with highly proliferative G2 and G3 NEN more accurately than the conventional criteria of grading or NEC/NET differentiation. High level Flt3L mRNA expression was associated with increased expression of genes related to immunogenic cell death, lymphocyte effector function and dendritic cell maturation, suggesting a less tolerogenic (more proinflammatory) phenotype of tumors with Flt3L induction. Importantly, circulating levels of Flt3L were also elevated in high grade NEN and correlated with patients´ progression-free and disease-related survival, thereby reflecting the results observed in tumor tissue.

Conclusions

Our results suggest Flt3L as a surrogate marker of an inflammatory tumor microenvironment. Therefore, we propose Flt3L as a prognostic biomarker for high grade GEP-NEN. Flt3L measurements in serum, which can be easily be incorporated into clinical routine, may hold the promise to guide patient stratification and tailor treatment decisions and should be further evaluated, especially in the context of immunotherapies.

Ethics Approval

The study was approved by the local ethics committee at Charité Universitätsmedizin Berlin, Germany (ethical approval number EA1/229/17) and patient informed consent was obtained.

Elevated Flt3L Predicts Long-Term Survival in Patients with High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms

BACKGROUND

The clinical management of high-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) is challenging due to disease heterogeneity, illustrating the need for reliable biomarkers facilitating patient stratification and guiding treatment decisions. FMS-like tyrosine kinase 3 ligand (Flt3L) is emerging as a prognostic or predictive surrogate marker of host tumoral immune response and might enable the stratification of patients with otherwise comparable tumor features.

METHODS

We evaluated Flt3L gene expression in tumor tissue as well as circulating Flt3L levels as potential biomarkers in a cohort of 54 patients with GEP-NEN.

RESULTS

We detected a prominent induction of Flt3L gene expression in individual G2 and G3 NEN, but not in G1 neuroendocrine tumors (NET). Flt3L mRNA expression levels in tumor tissue predicted the disease-related survival of patients with highly proliferative G2 and G3 NEN more accurately than the conventional criteria of grading or NEC/NET differentiation. High level Flt3L mRNA expression was associated with the increased expression of genes related to immunogenic cell death, lymphocyte effector function and dendritic cell maturation, suggesting a less tolerogenic (more proinflammatory) phenotype of tumors with Flt3L induction. Importantly, circulating levels of Flt3L were also elevated in high grade NEN and correlated with patients' progression-free and disease-related survival, thereby reflecting the results observed in tumor tissue.

CONCLUSIONS

We propose Flt3L as a prognostic biomarker for high grade GEP-NEN, harnessing its potential as a marker of an inflammatory tumor microenvironment. Flt3L measurements in serum, which can be easily be incorporated into clinical routine, should be further evaluated to guide patient stratification and treatment decisions.

Everolimus-induced pneumonitis in neuroendocrine neoplasms: correlation of CT findings and clinical signs

BACKGROUND

Everolimus, a mammalian target of rapamycin (mTOR)-inhibitor, is approved for the treatment of advanced neuroendocrine neoplasms (NEN). A rare major adverse event is the occurrence of drug-induced pneumonitis.

PURPOSE

To evaluate the correlation between clinical signs and computed tomography (CT) findings in everolimus-induced pneumonitis in patients with NEN.

MATERIAL AND METHODS

Ninety patients with NEN treated with everolimus were retrospectively enrolled (approved by our Institutional Review Board). All patients received chest CTs before the initiation of everolimus and during the treatment along with physical examinations. Clinical signs of pneumonitis were scored (symptomatic score) according to CTCAE v5.0. Pulmonary function tests (PFT) were evaluated if available. CT images were analyzed based on the severity of interstitial lung disease (ILD), the overall pneumonitis extent (PnE), and regarding presence of typical lung opacification patterns. Follow-up examinations of patients with pneumonitis were analyzed.

RESULTS

Pneumonitis was diagnosed in 18 (20%) patients. There was no significant correlation between symptomatic score or PFT and ILD score or PnE. In case of a cryptogenic organizing pneumonia pattern (n = 14), symptomatic scores were significantly lower (P = 0.035) than in case of other opacification patterns (n = 4). In the follow-up analysis, we could identify four different clinical courses.

CONCLUSION

CT detects everolimus-induced pneumonitis at a subclinical stage. In this setting, CT findings, clinical severity, and PFT do not clearly correlate. Opacification pattern analysis seems to be of importance when assessing the severity of CT findings. Asymptomatic patients with positive CT findings should be closely monitored to timely initiate specific treatment.

Automatized Hepatic Tumor Volume Analysis of Neuroendocrine Liver Metastases by Gd-EOB MRI-A Deep-Learning Model to Support Multidisciplinary Cancer Conference Decision-Making

BACKGROUND

Rapid quantification of liver metastasis for diagnosis and follow-up is an unmet medical need in patients with secondary liver malignancies. We present a 3D-quantification model of neuroendocrine liver metastases (NELM) using gadoxetic-acid (Gd-EOB)-enhanced MRI as a useful tool for multidisciplinary cancer conferences (MCC).

METHODS

Manual 3D-segmentations of NELM and livers (149 patients in 278 Gd-EOB MRI scans) were used to train a neural network (U-Net architecture). Clinical usefulness was evaluated in another 33 patients who were discussed in our MCC and received a Gd-EOB MRI both at baseline and follow-up examination (n = 66) over 12 months. Model measurements (NELM volume; hepatic tumor load (HTL)) with corresponding absolute (ΔabsNELM; ΔabsHTL) and relative changes (ΔrelNELM; ΔrelHTL) between baseline and follow-up were compared to MCC decisions (therapy success/failure).

RESULTS

Internal validation of the model's accuracy showed a high overlap for NELM and livers (Matthew's correlation coefficient (φ): 0.76/0.95, respectively) with higher φ in larger NELM volume (φ = 0.80 vs. 0.71; p = 0.003). External validation confirmed the high accuracy for NELM (φ = 0.86) and livers (φ = 0.96). MCC decisions were significantly differentiated by all response variables (ΔabsNELM; ΔabsHTL; ΔrelNELM; ΔrelHTL) (p < 0.001). ΔrelNELM and ΔrelHTL showed optimal discrimination between therapy success or failure (AUC: 1.000; p < 0.001).

CONCLUSION

The model shows high accuracy in 3D-quantification of NELM and HTL in Gd-EOB-MRI. The model's measurements correlated well with MCC's evaluation of therapeutic response.

Multicenter Analysis of Treatment Outcomes for Systemic Therapy in Well Differentiated Grade 3 Neuroendocrine Tumors (NET G3)

Well-differentiated grade 3 neuroendocrine tumors (NET G3) have been distinguished from poorly differentiated neuroendocrine carcinomas (NEC) in the most current WHO classifications. Commonly applied first-line chemotherapy protocols with cisplatin or carboplatin in combination with etoposide (PE) are less effective in NET G3 than NEC. Suggested alternative treatment protocols have not been studied in first-line therapy of NET G3 so far. We performed a retrospective analysis of patients with NET G3 in the databases of 3 German cancer centers. Out of 142 patients, 136 patients received palliative first-line therapy: overall response rate (ORR) was 35.1% for PE (n = 37), 56.4% for FOLFOX (n = 39), 27.3% for temozolomide/capecitabine (TEM/CAP) (n = 22), 45.0% for streptozotocin/5-fluorouracil (STZ/5-FU) (n = 20), and 16.7% for other (n = 18). Median progression-free survival (PFS) for PE was 6.9 months. Compared to PE, PFS in the other treatment groups was 6.9 months for FOLFOX (p = 0.333), 12.0 months for TEM/CAP (p = 0.093), 4.8 months for STZ/5-FU (p = 0.919), and 14.1 months for other (p = 0.014). In a univariate setting, all non-PE patients combined showed a significantly prolonged PFS vs. PE (9.0 months; p = 0.049) which could not be confirmed in a multivariate analysis. In conclusion, NET G3 with FOLFOX showed the highest ORR, and with TEM/CAP showed the longest PFS. Further prospective evaluation of the optimal therapeutic strategy for this tumor entity is needed.

Leptomeningeal Carcinomatosis: A Clinical Dilemma in Neuroendocrine Neoplasms

Central nervous system (CNS) involvement by paraneoplastic syndromes, brain metastases, or leptomeningeal carcinomatosis (LC) in patients with neuroendocrine neoplasms (NEN) has only been described in individual case reports. We evaluated patients with LC in four neuroendocrine tumor (NET) centers (Halle/Saale, Hamburg, Heidelberg, and Marburg) and characterized them clinically. In the study, 17 patients with a LC were defined with respect to diagnosis, clinic, and therapy. The prognosis of a LC is very poor, with 10 months in median overall survival (mOS). This is reflected by an even worse course in neuroendocrine carcinoma (NEC) G3 Ki-67 >55%, with a mOS of 2 months. Motor and sensory deficits together with vigilance abnormalities were common symptoms. In most cases, targeted radiation or temozolomide therapy was used against the LC. LC appears to be similarly devastating to brain metastases in NEN patients. Therefore, the indication for CNS imaging should be discussed in certain cases.

PD-L1 - inhibitors in neuroendocrine neoplasia: Results from a real-life study

Immune check-point inhibitors (ICIs) have changed our view on how to treat cancer. Despite their approval in treatment of many different cancers, efficacy of immune check-point inhibitors (ICI) in neuroendocrine neoplasia is limited and poorly understood. Established treatment options of neuroendocrine tumors (NET) and neuroendocrine carcinomas (NECs) are based on surgery, tumor-targeted medical treatments, Peptide Receptor Radionuclide Therapy (PRRT), and locoregional therapies. However, in many patients these treatments lose efficacy over time, and novel therapies are urgently needed. We report on 8 patients diagnosed with neuroendocrine neoplasms (NEN) that were treated with ICI (pembrolizumab, avelumab, nivolumab plus ipilimumab) as salvage therapy. In this cohort, we observed tumor response with partial remission in 3 patients and stable disease in 1 patient. Four patients showed progressive disease. Of note, responses were observed both in PD-L1 positive and PD-L1 negative patients. Here, we discuss clinical courses of these patients in the context of available literature to highlight limitations and drawbacks currently preventing the use of ICI in routine management of patients with NEN.

Models of Gastroenteropancreatic Neuroendocrine Neoplasms: Current Status and Future Directions

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare, heterogeneous group of tumors that originate from the endocrine system of the gastrointestinal tract and pancreas. GEP-NENs are subdivided according to their differentiation into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Since GEP-NENs represent rare diseases, only limited data from large prospective, randomized clinical trials are available, and recommendations for treatment of GEP-NEN are in part based on data from retrospective analyses or case series. In this context, tractable disease models that reflect the situation in humans and that allow to recapitulate the different clinical aspects and disease stages of GEP-NET or GEP-NEC are urgently needed. In this review, we highlight available data on mouse models for GEP-NEN. We discuss how these models reflect tumor biology of human disease and whether these models could serve as a tool for understanding the pathogenesis of GEP-NEN and for disease modeling and pharmacosensitivity assays, facilitating prediction of treatment response in patients. In addition, open issues applicable for future developments will be discussed.

Serum levels of miR-223 but not miR-21 are decreased in patients with neuroendocrine tumors

Background and aims

MicroRNAs (miRNAs) are profoundly involved into the pathophysiology of manifold cancers. Recent data suggested a pivotal role of miRNAs as biomarkers in different biological processes including carcinogenesis. However, their role in neuroendocrine tumors (NETs) is only poorly understood.

Methods

We determined circulating levels of miR-21 and miR-223 in 45 samples from patients with NET treated between 2010 and 2019 at our department and compared them to healthy controls. Results were correlated with clinical records.

Results

In the total cohort of Patients with NET, miR-223 presented significantly lower levels compared to healthy control samples. In contrast, levels of miR-21 indicated no significant changes between the two groups. Interestingly, despite being significantly downregulated in all NET patients, concentrations of miR-223 were independent of clinical or histopathological factors such as proliferation activity according to Ki-67 index, tumor grading, TNM stage, somatostatin receptor expression, presence of functional/ non-functional disease or tumor relapse. Moreover, in contrast to data from recent publications analyzing other tumor entities, levels of miR-223 serum levels did not reflect prognosis of patients with NET.

Conclusion

Lower concentrations of circulating miR-223 rather reflect the presence of NET itself than certain tumor characteristics. The value of miR-223 as a biomarker in NET might be limited to diagnostic, but not prognostic purposes.

A rare case of a patient with a high grade neuroendocrine tumor developing neutropenic sepsis after receiving PRRT combined with Capecitabine or Temozolomide: A case report

Neuroendocrine tumors (NET) are rare and demonstrate variable clinical behavior depending on the degree of tumor differentiation. Patients with poorly differentiated tumors (NET G3) have a poor prognosis. Systemic treatment with cytotoxic chemotherapy is considered to be the treatment of choice. In patients that are refractory or intolerant to first-line therapy, experts recommend peptide receptor radionuclide therapy (PRRT) in tumors that express somatostatin receptors. Recently, combinations of PRRT and chemotherapy were tested in patients with NET. Available data have reported promising tumor control rates and an excellent toxicity profile in cases where PRRT had been administered with capecitabine/temozolomide, even when administered as salvage therapy. The current study reported an exceptional case of advanced NET G3 with severe toxicity upon receiving PRRT in combination with capecitabine/temozolomide as third line therapy. The patient developed a life-threatening neutropenic fever, fungal pneumonia and necrotizing mastitis 23 days after the first cycle of therapy was administered. However, the treatment led to a significant reduction in tumor size. A total of 5 months after treatment initiation, the patient was alive and in excellent clinical condition with sustained tumor response. In summary, the current study presented a rare case of high grade NET exhibiting an almost complete response to PRRT in combination capecitabine/temozolomide, despite facing unexpected severe toxicity.

A case report of an excellent response to interferon- α in a patient with functional metastasized neuroendocrine tumor refractory to other treatments

INTRODUCTION

Interferon alpha (IFNα) has been used for a long time in patients with functionally active neuroendocrine tumors (NET). However, due to the unfavorable toxicity profile of interferon, the perceived limited efficacy as well as the development of novel substances, IFNα is only used sparingly in the treatment of NET to date.

PATIENTS CONCERNS AND DIAGNOSIS

We describe the case of a 63-year-old male patient with highly differentiated, functional NET of the ileum and synchronous liver metastasis.

INTERVENTIONS

After failure of classical therapies including dose-intensified somatostatin analog treatment and palliative primary tumor resection, a therapy with pegylated IFNα2a (135 μg/wk) was initiated. Following this treatment, the patient fully recovered from signs of hypersecretion and demonstrated an impressive tumor response.

OUTCOMES

Thirty months after initiating IFNα, the patient is still free of clinical symptoms and shows a sustained tumor response. Notably, no relevant side effects were observed.

CONCLUSION

Our case report supports the use of IFNα in patients with functional NET refractory to classical treatments.

Multicenter analysis of treatment outcomes for well differentiated grade 3 neuroendocrine tumors (NET G3)

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Background: Well differentiated grade 3 neuroendocrine tumors (NET G3) have been distinguished from poorly differentiated neuroendocrine carcinomas (NEC) in the most current WHO classifications from 2017 and 2019. Retrospective data suggest that commonly applied first-line chemotherapy protocols with cisplatin or carboplatin in combination with etoposide (PE) are less effective in NET G3 than NEC. Therefore, current treatment guidelines suggest alternative first-line treatment protocols like temozolomide-based (TEM), streptozotocin-based (STZ) and FOLFOX which have only been studied in second-line so far. The aim of this multicenter analysis was to evaluate treatment outcomes for NET G3 with a focus on the efficacy of different first-line regimens. Methods: We performed retrospective analysis of all patients with NET G3 in the NEN databases of 3 German cancer centers. All histopathological findings were reviewed by the investigators in order to comply with the most current WHO classification. Results: A total of 131 patients could be identified. Median Ki67 was 30 %, primary tumors were located in the pancreas in 71 % of cases, 20 patients had a history of prior NET G1/G2 diagnosis. Median overall survival (OS) was 138.1 months with a median follow-up of 20.4 months. 125 patients received palliative first-line therapy: PE n = 34, FOLFOX n = 36, TEM (mostly temozolomide+capecitabine) n = 21, STZ n = 19, other (including targeted agents, somatostatin analogues, PRRT and multimodal combination approaches) n = 15. Overall response (ORR) and disease control rate was 35.3 % and 67.6 % for PE, 52.8 % and 80.6 % for FOLFOX, 28.6 % and 66.7 % for TEM, 47.4 % and 68.4 % for STZ, 20.0 % and 73.3 % for other respectively. Median progression-free survival for PE was 5.2 months. Compared to PE, PFS in the other treatment groups was 6.0 months for FOLFOX (p = 0.164), 12.0 months for TEM (p = 0.059), 5.7 months for STZ (p = 0.519), 14.1 months for other (p = 0.003). All non-PE patients combined showed a significantly prolonged PFS vs. PE (9.0 vs. 5.2 months; p = 0.011). 89 patients received second-line systemic therapy with a median PFS of 5.3 months. Conclusions: In this first multicenter analysis of different treatment strategies for NET G3, patients receiving upfront treatment with non-PE regimens had a significantly prolonged PFS. Of the single defined protocols, FOLFOX showed the highest ORR, and TEM the longest PFS. Further prospective evaluation of the optimal therapeutic strategy for this newly defined tumor entity is needed.

Primary Neuroendocrine Neoplasms of the Breast: Case Series and Literature Review

Primary neuroendocrine carcinoma of the breast (NECB) as defined by the World Health Organization (WHO) in 2012 is a rare, but possibly under-diagnosed entity. It is heterogeneous as it entails a wide spectrum of diseases comprising both well-differentiated neuroendocrine tumors of the breast as well as highly aggressive small cell carcinomas. Retrospective screening of hospital charts of 612 patients (2008–2019) from our specialized outpatient unit for neuroendocrine neoplasia revealed five patients diagnosed with NECB. Given the low prevalence of these malignancies, correct diagnosis remains a challenge that requires an interdisciplinary approach. Specifically, NECB may be misclassified as carcinoma of the breast with neuroendocrine differentiation, carcinomas of the breast of no special type/invasive ductal carcinoma, or a metastasis to the breast. Therefore, this study presents multifaceted characteristics as well as the clinical course of these patients and discusses the five cases from our institution in the context of available literature.

Influence of Gender on Therapy and Outcome of Neuroendocrine Tumors of Gastroenteropancreatic Origin: A Single-Center Analysis

Introduction

Gender-specific treatment is gaining growing attention in various fields of medicine. In gastrointestinal cancer, influence of sex on outcome has been discussed, while this has not been the case in neuroendocrine tumors. Overall, the incidence of neuroendocrine neoplasms is rising, especially for appendiceal neuroendocrine neoplasms in women. Also, women seem to have a slight advantage in response to therapy, especially for liver metastases.

Objectives

This single-center analysis aimed to investigate gender-specific differences in our cohort related to distribution, therapy, and outcome.

Methods

Patients from the NET registry as well as the clinic database were evaluated retrospectively concerning overall survival and response to therapy with respect to gender. A subgroup analysis was carried out for patients with low grading and response to chemotherapy, as well as for patients with good and moderate grading receiving peptide receptor radionuclide therapy and for a group of patients with liver surgery.

Results

No specific differences could be detected for overall survival or response to therapy between male and female patients. Mean survival was estimated with 242.2 months (±10.39 SD) altogether and 221.7 months (± 13.02 SD) for male patients and 253.5 months (±15.24 SD) for female patients from the NET registry from initial diagnosis. There was no significant difference between female and male patients (p = 0.136). For patients receiving chemotherapy, overall survival from initial diagnosis was calculated with 26 months (±2.59) and did not show any significant differences between female and male patients 24.8 months (±2.81 SD) vs. 27.8 months (±3.86 SD, p = 0.87). Patients undergoing peptide receptor radionuclide therapy showed a median progression-free survival of 26.9 months (±2.82 SD), with 16.9 (±5.595 SD) and 26.9 months (±3.019 SD) for male and female patients, respectively (p = 0.2). In the group of patients with liver surgery, female patients reached an estimated overall survival of 64.7 months (±4.16 SD), male patients 65.1 months (±2.79 SD, p = 0.562).

Conclusion

Our cohort did not reveal significant differences in outcome and response to therapy with regards to gender.

Treatment outcomes of patients with G3 neuroendocrine neoplasms

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Background: Extra-pulmonary neuroendocrine carcinomas (NEC) and neuroendocrine tumors (NET) G3 are aggressive neoplasia that are associated with a limited prognosis. Data on this entity is scarce and optimal treatments are only poorly defined. Methods: 105 patients (♀ = 46; 43.8% and ♂ = 59; 56.2%) with histologically confirmed neuroendocrine carcinoma (NEC; n = 83) or neuroendocrine tumor G3 (NET G3; n = 12) or mixed neuroendocrine non-neuroendocrine neoplasms G3 (MiNEN G3; n = 10) were included into this study. Clinical and pathological characteristics at diagnosis, therapies, outcomes and survival data were recorded. Results: Primary tumor localizations included esophagus/stomach (n = 9; 8.7%), pancreas/duodenum (n = 29; 27.9%), appendix/colon/rectum (n = 25; 24.0%), the genitourinary tract (n = 9; 8.7%) and CUP (n = 32; 30.8%). Median Ki-67 across all patients was 70% (range 25-95) with a statistically significant difference in NEC G3 vs. NET G3 (74%, range 25-95 vs. 33.5%, range 25-69; p < .001). Median overall survival (mOS) was 19.2 (±1.6)months and was significantly higher in NET G3 (38 vs. 16.8 months in NEC; p = .012). First-line therapy in most patients was cisplatin or carboplatin in combination with etoposide (n = 64; 61.0%), followed by FOLFOX (n = 29; 27.6%). Twelve Patients (11.4%) received other chemotherapies. Best overall response to first-line chemotherapy was CR (5.7%), PR (52.4%) SD (17.1%) and PD (21%). In patients with Ki-67 < 55% (n = 40) no significant difference between the different regimens was found. In analyzing median PFS (mPFS) in patients with Ki-67 > 55% (n = 65) the combination of cis- or carboplatin with etoposide (mPFS 6.1±0.5 months) was superior to FOLFOX (mPFS 2.8±1.4 months; p = 0.038). Strikingly, in patients with small-cell NEC (n = 28) the combination of cisplatin/etoposide (mPFS 12.3±3months) showed a superior outcome compared to carboplatin/etoposide (mPFS: 6±1.4months; p = .022). Conclusions: Patients with non resectable NEN G3 should be treated with chemotherapy. In cases with proliferative index > 55% the 1st-line regimen of choice should be platinum in combination with etoposide. The difference in efficacy between carboplatin and cisplatin in our data should be evaluated in a prospective setting.

Surgery with Radical Intent: Is There an Indication for G3 Neuroendocrine Neoplasms?

BACKGROUND

While platinum-based chemotherapy represents the standard treatment for advanced grade 3 (G3) neuroendocrine neoplasms (NENs) according to the European Neuroendocrine Tumor Society guidelines, the role of radical-intended surgery in these patients, as well as the use of adjuvant chemotherapy, are still controversial. The aim of the present work is to describe, in a retrospective series of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) G3, the overall survival (OS) rate and risk factors for death after radical surgery. Secondary aims are the description of median recurrence-free survival (RFS) and of the role of adjuvant chemotherapy.

PATIENTS AND METHODS

Multicenter analysis of a series of stage I-III GEP-NEN G3 patients receiving radical surgery (R0/R1) with/without adjuvant chemotherapy was performed.

RESULTS

Sixty patients from eight neuroendocrine tumor (NET) referral centers, with median follow-up of 23 months (5-187 months) were evaluated. While 28.6% of cases had NET G3, 71.4% had neuroendocrine carcinoma G3 (NEC G3). The 2-year OS rate after radical surgery was 64.5%, with a statistically significant difference in terms of Ki67 threshold (cut-off 55%, P = 0.03) and tumor differentiation (NEC G3 vs. NET G3, P = 0.03). Median RFS after radical surgery was 14 months, and 2-year RFS rate was 44.9%. Use of adjuvant chemotherapy provided no benefit in terms of either OS or RFS in this series.

CONCLUSIONS

Surgery with radical intent might represent a valid option for GEP-NEN G3 patients with locoregional disease, especially with Ki67 value ≤ 55%.

Gastric neuroendocrine neoplasias: manifestations and comparative outcomes

Although gastric neuroendocrine neoplasias (gNEN) are an orphan disease, their incidence is rising. The heterogeneous clinical course powers the ongoing discussion of the most appropriate classification system and management. Prognostic relevance of proposed classifications was retrospectively analysed in 142 patients from a single tertiary referral centre. Baseline, management and survival data were acquired for statistical analyses. The distribution according to the clinicopathological typification was gNEN-1 (n = 86/60.6%), gNEN-2 (n = 7/4.9%), gNEN-3 (n = 24/16.9%) and gNEN-4 (n = 25/17.6%), while hypergastrinemia-associated gNEN-1 and -2 were all low-grade tumours (NET-G1/2), formerly termed sporadic gNEN-3 could be subdivided into gNEN-3 with grade 1 or 2 and gNEN-4 with grade 3 (NEC-G3). During follow-up 36 patients died (25%). The mean overall survival (OS) of all gNEN was 14.2 years. The OS differed statistically significant across all subgroups with either classification system. According to UICC 2017 TNM classification, OS differed for early and advanced stages, while WHO grading indicated poorer prognosis for NEC-G3. Cox regression analysis confirmed the independent prognostic validity of either classification system for survival. Particularly careful analysis of the clinical course of gNEN-1 (ECLomas, gastric carcinoids) confirmed their mostly benign, but recurrent and extremely slowly progressive behaviour with low risk of metastasis (7%) and an efficient long-term control by repetitive endoscopic procedures. Our study provides evidence for the validity of current classifications focusing on typing, grading and staging. These are crucial tools for risk stratification, especially to differentiate gNEN-1 as well as sporadic gNET and gNEC (gNEN-3 vs -4).

Abstract 919: Clinical relevance of comprehensive genomic analysis in patients with advanced-stage neuroendocrine neoplasms: Results from the MASTER trial of the German Cancer Consortium

Therapeutic options for neuroendocrine neoplasms (NEN) are limited. Within the MASTER program, a multi-institutional registry trial for prospective stratification of younger adults with advanced-stage cancer across all histologies and patients with rare tumors conducted under the auspices of NCT Heidelberg/Dresden and the German Cancer Consortium, we apply prospective whole-exome/genome sequencing (WES/WGS) and RNA sequencing (RNA-seq) to determine therapeutic choices for individual patients who have exhausted standard therapy options. We here report the clinical and molecular characteristics of the NEN cohort within this study. Between 2013 and 2018, 108 patients (male, n=65; female, n=43) were enrolled. Histologies according to the 2017 WHO Classification were neuroendocrine tumor grade 1 (NET G1), n=8; NET G2, n=31; NET G3, n=9; neuroendocrine carcinoma, n=49; and mixed neuroendocrine/non-neuroendocrine neoplasm, n=11. Primary tumor sites were gastrointestinal tract, n=30; pancreas, n=31; thorax, n=21; genitourinary system, n=11; head and neck, n=5; and other regions, n=10. All patients had advanced-stage disease and had received a median of 2 prior lines of systemic therapy. WES, WGS, and RNA-seq were performed in 69, 40, and 87 patients, respectively. Clinical evaluation of germline and somatic molecular data (single-nucleotide variants, small insertions and deletions, copy number variations, mutational burden, mutational signatures, homologous recombination deficiency scores, gene expression patterns, etc.) from 105 patients by a dedicated molecular tumor board yielded evidence-based recommendations for clinical management in 91 cases (87%). Treatment recommendations were grouped as follows: PARP inhibition, n=35; immunotherapy, n=27; mTOR inhibition, n=22; CDK4/6 inhibition, n=15; tyrosine or serine/threonine kinase inhibition, n=57 (ALK, n=1; ERBB, n=6; FGFR, n=10; MET, n=5; RET, n=12; VEGFR, n=4, MEK, n=9; other, n=10), DNA-crosslinking chemotherapy, n=16; anti-claudin18.2 antibody, n=5; BET inhibition, n=5; and DLL3 antibody, n=5. As of November 2018, at least 18 patients had received molecularly guided treatment (PARP inhibition, immunotherapy, mTOR inhibition, tyrosine or serine/threonine kinase inhibition) of which 11 were evaluable for response (partial response, n=4; stable disease, n=2; progressive diseases, n=5). Twenty-seven patients died before therapy could be started, 16 are currently receiving other regimens, and for the remaining patients no follow-up data are available yet. In conclusion, comprehensive molecular profiling offers valuable insight into to the genomic and transcriptomic landscape of NEN and creates additional therapeutic opportunities in a subset of patients.

Citation Format: Simon Kreutzfeldt, Leonidas Apostolidis, Malgorzata Oles, Peter Horak, Christoph E. Heilig, Christoph Heining, Barbara Hutter, Laura Gieldon, Barbara Klink, Mario Lamping, Damian T. Rieke, Sebastian Uhrig, Henning Jann, Ulrich F. Pape, Albrecht Stenzinger, Eva C. Winkler, Bertram Wiedenmann, Dirk Jäger, Benedikt Brors, Evelin Schröck, Ulrich Keilholz, Marianne Pavel, Hanno Glimm, Stefan Fröhling. Clinical relevance of comprehensive genomic analysis in patients with advanced-stage neuroendocrine neoplasms: Results from the MASTER trial of the German Cancer Consortium [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 919.

Somatostatin Analogues in the Treatment of Neuroendocrine Tumors: Past, Present and Future

In recent decades, the incidence of neuroendocrine tumors (NETs) has steadily increased. Due to the slow-growing nature of these tumors and the lack of early symptoms, most cases are diagnosed at advanced stages, when curative treatment options are no longer available. Prognosis and survival of patients with NETs are determined by the location of the primary lesion, biochemical functional status, differentiation, initial staging, and response to treatment. Somatostatin analogue (SSA) therapy has been a mainstay of antisecretory therapy in functioning neuroendocrine tumors, which cause various clinical symptoms depending on hormonal hypersecretion. Beyond symptomatic management, recent research demonstrates that SSAs exert antiproliferative effects and inhibit tumor growth via the somatostatin receptor 2 (SSTR2). Both the PROMID (placebo-controlled, prospective, randomized study in patients with metastatic neuroendocrine midgut tumors) and the CLARINET (controlled study of lanreotide antiproliferative response in neuroendocrine tumors) trial showed a statistically significant prolongation of time to progression/progression-free survival (TTP/PFS) upon SSA treatment, compared to placebo. Moreover, the combination of SSA with peptide receptor radionuclide therapy (PRRT) in small intestinal NETs has proven efficacy in the phase 3 neuroendocrine tumours therapy (NETTER 1) trial. PRRT is currently being tested for enteropancreatic NETs versus everolimus in the COMPETE trial, and the potential of SSTR-antagonists in PRRT is now being evaluated in early phase I/II clinical trials. This review provides a synopsis on the pharmacological development of SSAs and their use as antisecretory drugs. Moreover, this review highlights the clinical evidence of SSAs in monotherapy, and in combination with other treatment modalities, as applied to the antiproliferative management of neuroendocrine tumors with special attention to recent high-quality phase III trials.

Clinical impact of comprehensive versus targeted genomic analysis for precision oncology

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Background: Panel sequencing (PS) has become a standard-of-care in cancer diagnostics. More comprehensive analyses such as whole-exome (WES) or RNA sequencing (RNAseq) allow for the detection of rare and unknown genetic aberrations that are not covered by predefined assays. The clinical impact of targeted versus comprehensive genomic assays were analyzed in patients presented at the Charité Molecular Tumor Board (MTB). Methods: Patients (pts) with advanced and/or metastatic cancer for whom no standard therapy was available were discussed in the MTB to allocate diagnostic profiling and guide biomarker-based treatment (BBT). Pts had to be < 50 years of age or diagnosed with a rare tumor entity to undergo WES/RNAseq, performed on fresh tissue. If ineligible, standard PS was performed on archival tissue. BBT recommendations, ranked by pre-specified evidence levels, were made by the MTB and pts were followed up. Results: 228 patients (median age 49 years, 108 female and 120 male) were discussed in the MTB between January 2016 and February 2019. We assigned 73 and 155 pts to PS and WES/RNAseq and results were obtained for 78.1% (n = 57/73) and 54.8% (n = 85/155) pts, respectively. Sequencing failed for 11 (PS; 15.1%) and 62 (WES/RNAseq; 40%) pts, most commonly due to insufficient tissue (n = 29). Sequencing was ongoing in 5 (PS) and 8 (WES/RNAseq) pts at the time of analysis. A median of 2 BBTs were recommended for 75.4% (43/57) of PS (range r: 1-3) and 90.6% (77/85) of WES/RNAseq pts (r: 1-6) each. 22% (n = 17/77) of WES/RNAseq pts had ≥4 BBTs made by the MTB. Treatment was initiated in 30.2% (n = 13/43) of PS and 40.2% (n = 31/77) of WES/RNAseq pts. Clinical benefit rates (CBRs) were 23.1% (2 PR, 1 SD) for PS and 45.2% (2 CR, 3 PR, 9 SD) for WES/RNAseq pts. Overall survival data was immature at the time of analysis. Conclusions: Utilizing WES/RNAseq is a feasible approach to perform tumor profiling in a heterogeneous cohort. We here show a higher rate of pts receiving confident evidence-based treatment recommendations in the WES/RNAseq group and a higher rate of treatment initiation. The CBR nearly doubled in the WES/RNAseq cohort when compared to standard PS pts, thus emphasizing the need for larger comparative analyses to guide diagnostic decision-making.

Competitive Testing of the WHO 2010 versus the WHO 2017 Grading of Pancreatic Neuroendocrine Neoplasms: Data from a Large International Cohort Study

BACKGROUND

The World Health Organization (WHO) and the American Joint Cancer Committee (AJCC) modified the grading of pancreatic neuroendocrine neoplasms from a three-tier (WHO-AJCC 2010) to a four-tier system by introducing the novel category of NET G3 (WHO-AJCC 2017).

OBJECTIVES

This study aims at validating the WHO-AJCC 2017 and identifying the most effective grading system.

METHOD

A total of 2,102 patients were enrolled; entry criteria were: (i) patient underwent surgery; (ii) at least 2 years of follow-up; (iii) observation time up to 2015. Data from 34 variables were collected; grading was assessed and compared for efficacy by statistical means including Kaplan-Meier method, Cox regression analysis, Harrell's C statistics, and Royston's explained variation in univariable and multivariable analyses.

RESULTS

In descriptive analysis, the two grading systems demonstrated statistically significant differences for the major category sex but not for age groups. In Cox regression analysis, both grading systems showed statistically significant differences between grades for OS and EFS; however, no statistically significant difference was observed between the two G3 classes of WHO-AJCC 2017. In multivariable analysis for the two models fitted to compare efficacy, the two grading systems performed equally well with substantially similar optimal discrimination and well-explained variation for both OS and EFS. The WHO-AJCC 2017 grading system retained statistically significant difference between the two G3 classes for OS but not for EFS.

CONCLUSIONS

The WHO-AJCC 2017 grading system is at least equally performing as the WHO-AJCC 2010 but allows the successful identification of the most aggressive PanNET subgroup. Grading is confirmed as probably the most powerful tool for predicting patient survival.

Identifying Prognostic Factors for Well-Differentiated Metastatic Pancreatic Neuroendocrine Tumours: A Retrospective International Multicentre Cohort Study

Pancreatic neuroendocrine tumours (pNETs) represent rare neoplasms of all NETs often presenting without functional activity. Many sporadic non-functioning pNET patients are already metastatic at the time of diagnosis, and the therapeutic approach to such patients is mostly palliative. In this international, multicentre, retrospective cohort study, we assessed the prognostic value of a set of anthropometric, clinical, biochemical, radiological and pathological parameters at baseline and the impact of the therapeutic strategies on the survival of patients with sporadic grade 1/2, stage IV, non-functioning pNETs. Three hundred and twelve consecutive patients diagnosed between 1993 and 2010 were included. The median overall survival (OS) was 6.6 years and survival at 5 and 10 years was 62 and 34% respectively. On univariate analysis, Eastern Cooperative Oncology Group (ECOG) status ≥2, grade 2, bilobar hepatic metastases, synchronous metastases, and high chromogranin A, alkaline-phosphatase and lactic-dehydrogenase were associated with a significant reduction of OS. Palliative/curative surgery and loco-regional hepatic interventions were significant factors improving OS. On multivariate analysis, ECOG status ≥2, synchronous metastases, Ki-67 ≥10%, and high alkaline-phosphatase correlated significantly with an increased risk of death. Both palliative/curative surgery and loco-regional hepatic interventions had a positive impact on OS. Although most parameters did not prove to be independent OS predictors at multivariate analysis, they showed a tendency towards that. Future prospective studies including larger patient populations may give greater clarity. We believe the integration of these parameters has the potential to provide a reliable prognostic score for the stratification of patients with sporadic well-differentiated metastatic non-functioning pNETs.

Malnutrition Predicts Clinical Outcome in Patients with Neuroendocrine Neoplasia

Malnutrition is a common problem in oncological diseases, influencing treatment outcomes, treatment complications, quality of life and survival. The potential role of malnutrition has not yet been studied systematically in neuroendocrine neoplasms (NEN), which, due to their growing prevalence and additional therapeutic options, provide an increasing clinical challenge to diagnosis and management. The aim of this cross-sectional observational study, which included a long-term follow-up, was therefore to define the prevalence of malnutrition in 203 patients with NEN using various methodological approaches, and to analyse the short- and long-term outcome of malnourished patients. A detailed subgroup analysis was also performed to define risk factors for poorer outcome. When applying malnutrition screening scores, 21-25% of the NEN patients were at risk of or demonstrated manifest malnutrition. This was confirmed by anthropometric measurements, by determination of serum surrogate parameters such as albumin as well as by bioelectrical impedance analysis (BIA), particularly phase angle α. The length of hospital stay was significantly longer in malnourished NEN patients, while long-term overall survival was highly significantly reduced. Patients with high-grade (G3) neuroendocrine carcinomas, progressive disease and undergoing chemotherapy were at particular risk of malnutrition associated with a poorer outcome. Multivariate analysis confirmed the important and highly significant role of malnutrition as an independent prognostic factor for NEN besides proliferative capacity (G3 NEC). Malnutrition is therefore an underrecognized problem in NEN patients which should systematically be diagnosed by widely available standard methods such as Nutritional Risk Screening (NRS), serum albumin assessment and BIA, and treated to improve both short- and long-term outcomes.

NET Blood Transcript Analysis Defines the Crossing of the Clinical Rubicon: When Stable Disease Becomes Progressive

BACKGROUND/AIMS

A key issue in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is early identification and prediction of disease progression. Clinical evaluation and imaging are limited due to the lack of sensitivity and disease indolence. We assessed the NETest as a predictive and prognostic marker of progression in a long-term follow-up study.

METHODS

GEP-NETs (n = 34) followed for a median 4 years (2.2-5.4) were evaluated. WHO tumor grade/stage grade 1: n = 17, grade 2: n = 14, grade 3: n = 1 (for 2, no grade was available); 31 (91%) were stage IV. Baseline and longitudinal imaging and blood biomarkers were available in all, and progression was defined per standard clinical protocols (RECIST 1.0). The NETest was measured by quantitative PCR of blood and multianalyte algorithmic analysis (disease activity scaled 0-100% with low <40% and high activity risk cutoffs >80%); chromogranin A (CgA) was measured by radioimmunoassay (normal <150 µg/l); progression-free survival (PFS) was analyzed by Cox proportional-hazard regression and Kaplan-Meier analysis.

RESULTS

At baseline, 100% were NETest positive, and CgA was elevated in 50%. The only baseline variable (Cox modeling) associated with PFS was NETest (hazard ratio = 1.022, 95% confidence interval = 1.005-1.04; p < 0.012). Using Kaplan-Meier analyses, the baseline NETest (>80%) was significantly associated (p = 0.01) with disease progression (median PFS 0.68 vs. 2.78 years with <40% levels). The NETest was more informative (96%) than CgA changes (<under>></under>25%) in consistently predicting disease alterations (40%, p < 2 × 10-5, χ2 = 18). The NETest had an earlier time point change than imaging (1.02 ± 0.15 years). Baseline NETest levels >40% in stable disease were 100% prognostic of disease progression versus CgA (χ2 = 5, p < 0.03). Baseline NETest values <40% accurately (100%) predicted stability over 5 years (p = 0.05, χ2 = 3.8 vs. CgA).

CONCLUSION

The NETest correlated with a well-differentiated GEP-NET clinical status. The NETest has predictive and prognostic utility for GEP-NETs identifying clinically actionable alterations ∼1 year before image-based evidence of progression.

Increased Activity of the Immunoregulatory Enzyme Indoleamine-2,3-Dioxygenase with Consecutive Tryptophan Depletion Predicts Death in Patients with Neuroendocrine Neoplasia

BACKGROUND/AIMS

Data from a considerable number of malignancies demonstrate that depletion of the essential amino acid tryptophan via induction of the immunoregulatory enzyme indoleamine-2,3-dioxygenase (IDO) serves as an important tumour escape strategy and is of prognostic importance. Here we investigate the predictive value of the activity of IDO as well as levels of tryptophan and respective downstream catabolites in a large cohort of patients with neuroendocrine neoplasms (NEN).

METHODS

142 consecutive Caucasian patients (62 male, aged 60.3 ± 11.9 years) with histologically confirmed NEN were systematically analysed in a retrospective blinded end point analysis. Patients were followed up for a mean period of about 3.9 ± 1.9 years. Clinical outcome, levels of established biomarkers, and tryptophan degradation markers (assessed using tandem mass spectrometry) including estimated IDO activity were recorded. Cox proportional hazards regression models were performed for the assessment of prognostic power.

RESULTS

We found that baseline tryptophan levels were significantly lower and IDO activity was significantly increased in non-survivors. The risk for death inclined stepwise and was highest in patients in the upper tertile of IDO activity. Cox proportional regression models identified IDO activity as an independent predictor of death.

CONCLUSIONS

In this retrospective analysis, we observed that baseline activity of the immunoregulatory enzyme IDO was significantly increased in non-survivors. IDO activity was identified as an independent predictor of death in this cohort of NEN patients. Whether IDO activity or tryptophan depletion serves to guide future therapeutic interventions in NEN remains to be established.

Management of follow-up of neuroendocrine neoplasias

Neuroendocrine neoplasias (NEN) comprise heterogeneous epithelial neoplasms with a large variety of clinical presentations, treatment options and outcomes. Since potentially all NEN bear malignant potential it is important for long-term clinical management and improvement of outcome to decide on successful and oncologically and economically meaningful follow-up strategies. Evidence-based outcome data validating specific follow-up strategies are, however, not available to date and thus outcome data, known prognostic factors and clinical experience guide the decisions on follow-up regimens. The review summarizes general recommendations as well as specific considerations based on tumor entities, clinicopathological tumor characteristics and clinical experience. Follow-up shall serve the patient to improve outcome, benefit from more effective therapies and suffer less from unnecessary and/or toxic therapeutic interventions and finally preserve or gain a good quality of life.

Placental growth factor supports neuroendocrine tumor growth and predicts disease prognosis in patients

Placental growth factor (PlGF), a VEGF-homolog implicated in tumor angiogenesis and adaptation to antiangiogenic therapy, is emerging as candidate target in malignancies. Here, we addressed the expression, function, and prognostic value of PlGF in neuroendocrine tumors (NETs). PlGF was determined in NET patients' sera collected retrospectively (n=88) and prospectively (n=87) using Roche-Elecsys and correlated with clinicopathological data. Tumoral PlGF was evaluated by immunohistochemistry, effects of PlGF on proliferation and migration in vitro were assessed using different NET cell lines and effects on tumor growth in vivo in orthotopic xenografts. Circulating and tumoral PlGF was elevated in patients with pancreatic NETs (pNETs) compared with control sera and respective healthy tissue. De novo PlGF expression occurred primarily in the tumor stroma, suggesting paracrine stimulatory circuits. Indeed, PlGF enhanced NET proliferation and migration in vitro and, conversely, neutralizing antibodies to PlGF reduced tumor growth in vivo. Elevated circulating PlGF levels in NET patients correlated with advanced tumor grading and were associated with reduced tumor-related survival in pNETs. Subsequent determinations confirmed and extended our observation of elevated PlGF levels in a prospective cohort of grade 1 and grade 2 pNETs (n=30) and intestinal NETs (n=57). In low-grade pNETs, normal circulating PlGF levels were associated with better survival. In intestinal NETs, circulating PlGF above median emerged as an independent prognostic factor for shorter time-to-progression in multivariate analyses. These data assign to PlGF a novel function in the pathobiology of NETs and propose PlGF as a prognostic parameter and therapeutic target.

Impact of octreotide long-acting release on tumour growth control as a first-line treatment in neuroendocrine tumours of pancreatic origin

BACKGROUND

Somatostatin analogues (SSA) are widely used in the treatment of patients with functioning and non-functioning neuroendocrine tumours (NET). The aim of our investigation was to evaluate the antiproliferative effect of SSA in patients with pancreatic NET.

METHODS

We retrospectively analysed records of 43 patients with pancreatic NET treated at our clinic with octreotide long-lasting release as a first-line therapy. The aim of our study was to investigate the overall best response according to the RECIST criteria, overall best response defined as disease control rate (SD+PR), response and disease control rate at 12 months, and time to tumour progression (TTP).

RESULTS

The mean age (± SD) of the patients (16 female/27 male) at initial diagnosis was 54.7 ± 11.86 years. At the start of therapy, 39 of 43 patients were classified as stage IV according to ENETS-TNM. Tumours were graded, based on MiB-1/Ki67 staining, as G1 (n = 8), G2 (n = 30) or unknown (n = 5). The octreoscan was positive in 37 patients, negative in 2 and unknown in 4 cases. Nineteen patients had functioning tumours, 24 patients had non-functioning tumours. Median overall survival was 98 months, and median TTP was 13 months. Analysis of grading showed a statistically significant influence on TTP when comparing the median TTP for Ki67 >10% with Ki67 <5% (p = 0.009) and Ki67 5-10% (p = 0.036).

CONCLUSION

SSA may be considered as a first-line treatment for antiproliferative purposes in metastatic NET of the pancreas. Patients with a proliferation index <10% displayed a more durable response compared to those with a higher proliferation index.