The epidemiology of metastases in neuroendocrine tumors

Pancreatic Neuroendocrine Neoplasms: Does Sex Matter?

Genetic and molecular disparities between men and women have a role in the differing incidence, pathophysiology, clinical signs, and treatment outcome of several cancers. Sex differences in cancer incidence are attributed to regulation at the genetic/molecular level and to sex hormones that in turn modulate gene expression in various cancers. Sex differences in the incidence of cancer, its aggressiveness, and the disease prognosis have been reported for several types of cancer but little is known for pancreatic neuroendocrine neoplasms (PNENs). The aim of this Opinion article is to provide an overview of sex differences in PNENs in terms of epidemiology, pathophysiology, treatment responses, prognosis, and survival. This overview might allow better tailoring of the management of PNENs.

The Role of Interventional Radiology for the Treatment of Hepatic Metastases from Neuroendocrine Tumor: An Updated Review

Interventional radiology plays an important role in the management of patients with neuroendocrine tumor liver metastasis (NELM). Transarterial embolization (TAE), transarterial chemoembolization (TACE), and selective internal radiation therapy (SIRT) are intra-arterial therapies available for these patients in order to improve symptoms and overall survival. These treatment options are proposed in patients with NELM not responding to systemic therapies and without extrahepatic progression. Currently, available data suggest that TAE should be preferred to TACE in patients with NELM from extrapancreatic origin because of similar efficacy and better patient tolerance. TACE is more effective in patients with pancreatic NELM and SIRT has shown promising results along with good tolerance. However, large randomized controlled trials are still lacking in this setting. Available literature mainly consists in small sample size and retrospective studies with important technical heterogeneity. The purpose of this review is to provide an updated overview of the currently reported endovascular interventional radiology procedures that are used for the treatment of NELM.

Pancreatic neuroendocrine tumors G3 and pancreatic neuroendocrine carcinomas: Differences in basic biology and treatment

In 2017 the World Health Organization revised the criteria for classification of pancreatic neuroendocrine neoplasms (pNENs) after a consensus conference at the International Agency for Research on Cancer. The major change in the new classification was to subclassify the original G3 group into well-differentiated pancreatic neuroendocrine tumors G3 (pNETs G3) and poorly differentiated pancreatic neuroendocrine carcinomas (pNECs), which have been gradually proven to be completely different in biological behavior and clinical manifestations in recent years. In 2019 this major change subsequently extended to NENs involving the entire digestive tract. The updated version of the pNENs grading system marks a growing awareness of these heterogeneous tumors. This review discusses the clinicopathological, genetic and therapeutic features of poorly differentiated pNECs and compare them to those of well-differentiated pNETs G3. For pNETs G3 and pNECs (due to their lower incidence), there are still many problems to be investigated. Previous studies under the new grading classification also need to be reinterpreted. This review summarizes the relevant literature from the perspective of the differences between pNETs G3 and pNECs in order to deepen understanding of these diseases and discuss future research directions.

Cardiac Metastases in Neuroendocrine Tumors: 68Ga-DOTATATE PET/CT With Cardiac Magnetic Resonance Correlation

Neuroendocrine tumor (NET) cardiac metastases can be associated with complications including ventricular outflow obstruction, arrhythmias, heart failure, and cardiac arrest, warranting intervention. Anatomical characterization of these lesions via cardiac magnetic resonance (CMR) is helpful to assess and predict the risk of complications and guide therapy. Images of 2 patients with small bowel NET related cardiac metastases are described on Ga-DOTATATE PET/CT and CMR. The lesions were significantly smaller and more obscure on CMR compared with PET/CT. On CMR, T2-weighted dark blood images and late gadolinium enhancement images offered the most conspicuous detection of the NET myocardial metastases in these cases.

Incidence, treatment, and survival analysis in esophageal neuroendocrine carcinoma population

BACKGROUND

As a subtype of esophageal neuroendocrine neoplasms (ENENs), esophageal neuroendocrine carcinoma (ENEC) is rare. ENEC can be poorly differentiated and highly aggressive. This study aims to illustrate the incidence, treatment, and prognosis of ENEC by using a population-based database.

METHODS

We collected clinicopathological data [1975-2016] of ENEC, esophageal adenocarcinoma (EACA), and esophageal squamous cell carcinoma (ESqCC) from the Surveillance, Epidemiology and End Results (SEER) database, and analyzed their incidence, treatment, and prognosis.

RESULTS

A total of 60,238 cases were in our study cohort, including ENEC (n=686), EACA (n=26,575), and ESqCC (n=32,977). The incidence of ENEC in 2016 was 0.044 per 100,000 persons. The tumor grade of ENEC was significantly higher than that of EACA and ESqCC (P<0.001). Both cancer-specific survival (CSS) and overall survival (OS) of ENEC were significantly worse than those of EACA and ESqCC (P<0.001). Kaplan-Meier analysis showed significant improvement of CSS and OS by surgery, radiotherapy, and chemotherapy (all P<0.001). Besides, compared with monotherapies, combinational therapies brought more benefits to both CSS and OS of patients with ENEC.

CONCLUSIONS

Our population-based evidence revealed that ENEC, as a rare cancer, had a worse prognosis, compared with EACA and ESqCC. Surgery, chemotherapy, and radiotherapy can all improve the prognosis of ENEC patients. Combinational therapy can yield a better prognosis than monotherapy.

Liver metastases and the efficacy of the PD-1 or PD-L1 inhibitors in cancer: a meta-analysis of randomized controlled trials

Objective: To explore the relations between liver metastases (LM) and the efficacy of the treatments with programmed cell death 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors.

Method: Pubmed, Embase, American Society of Clinical Oncology and the European Society for Medical Oncology were searched to select eligible studies about PD-1 or PD-L1 inhibitors (Nivolumab, Pembrolizumab, Cemiplimab, Avelumab, Durvalumab, and Atezolizumab). We included only the original randomized controlled trials (RCTs), including the hazard ratios (HR) of death in both patients with LM and patients without LM. Then the data were extracted for the meta-analysis. Subgroup analyses of cancer types and drug types were also performed.

Results: 5293 patients [1246 (24%) patients with LM, and 4047 (76%) patients without LM] from the eight RCTs were included for the final analysis. The pooled hazard ratio (HR) of death in the patients with LM was 0.82 (95% CI, 0.71 to 0.93, P = .003) while the pooled HR in the patients without LM was 0.72 (95% CI, 0.66 to 0.79, P < .001). Additionally, no significant difference was found between the two groups (P = .137).

Conclusion: No statistically significant association of liver metastases with the efficacy of treatments with PD-1 or PD-L1 inhibitors in the treatment of advanced or metastatic cancer was found in the stratified analyses. Moreover, future studies about the safety of the PD-1 or PD-L1 inhibitors in patients with or without liver metastases are warranted.

Bone Metabolism and Vitamin D Implication in Gastroenteropancreatic Neuroendocrine Tumors

Patients affected by gastroenteropancreatic–neuroendocrine tumors (GEP–NETs) have an increased risk of developing osteopenia and osteoporosis, as several factors impact on bone metabolism in these patients. In fact, besides the direct effect of bone metastasis, bone health can be affected by hormone hypersecretion (including serotonin, cortisol, and parathyroid hormone-related protein), specific microRNAs, nutritional status (which in turn could be affected by medical and surgical treatments), and vitamin D deficiency. In patients with multiple endocrine neoplasia type 1 (MEN1), a hereditary syndrome associated with NET occurrence, bone damage may carry other consequences. Osteoporosis may negatively impact on the quality of life of these patients and can increment the cost of medical care since these patients usually live with their disease for a long time. However, recommendations suggesting screening to assess bone health in GEP–NET patients are missing. The aim of this review is to critically analyze evidence on the mechanisms that could have a potential impact on bone health in patients affected by GEP–NET, focusing on vitamin D and its role in GEP–NET, as well as on factors associated with MEN1 that could have an impact on bone homeostasis.

Workup of Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors of the gastrointestinal tract or pancreas are rare. Their presentation overlaps with other intra-abdominal neoplasms, but can have unique features. The workup involves recognition of unusual clinical features associated with the tumors, imaging, analysis of blood or urine concentrations, and biopsy. Functional imaging takes advantage of the neuroendocrine tumor-specific expression of somatostatin receptors. There are characteristic features supporting the diagnosis on contrast-enhanced cross-sectional imaging. The use of tumor markers for biochemical diagnosis requires an understanding of the confounding variables affecting these assays. There are unique and specific immunohistochemical staining and grading requirements for appropriate diagnosis of these tumors.

Impact of liver tumour burden, alkaline phosphatase elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate: an analysis of the NETTER-1 study

PURPOSE

To assess the impact of baseline liver tumour burden, alkaline phosphatase (ALP) elevation, and target lesion size on treatment outcomes with ¹⁷⁷Lu-Dotatate.

METHODS

In the phase 3 NETTER-1 trial, patients with advanced, progressive midgut neuroendocrine tumours (NET) were randomised to 177Lu-Dotatate (every 8 weeks, four cycles) plus octreotide long-acting release (LAR) or to octreotide LAR 60 mg. Primary endpoint was progression-free survival (PFS). Analyses of PFS by baseline factors, including liver tumour burden, ALP elevation, and target lesion size, were performed using Kaplan-Meier estimates; hazard ratios (HRs) with corresponding 95% CIs were estimated using Cox regression.

RESULTS

Significantly prolonged median PFS occurred with ¹⁷⁷Lu-Dotatate versus octreotide LAR 60 mg in patients with low (< 25%), moderate (25-50%), and high (> 50%) liver tumour burden (HR 0.187, 0.216, 0.145), and normal or elevated ALP (HR 0.153, 0.177), and in the presence or absence of a large target lesion (diameter > 30 mm; HR, 0.213, 0.063). Within the ¹⁷⁷Lu-Dotatate arm, no significant difference in PFS was observed amongst patients with low/moderate/high liver tumour burden (P = 0.7225) or with normal/elevated baseline ALP (P = 0.3532), but absence of a large target lesion was associated with improved PFS (P = 0.0222). Grade 3 and 4 liver function abnormalities were rare and did not appear to be associated with high baseline liver tumour burden.

CONCLUSIONS

¹⁷⁷Lu-Dotatate demonstrated significant prolongation in PFS versus high-dose octreotide LAR in patients with advanced, progressive midgut NET, regardless of baseline liver tumour burden, elevated ALP, or the presence of a large target lesion. Clinicaltrials.gov : NCT01578239, EudraCT: 2011-005049-11.

CT texture analysis of liver metastases in PNETs versus NPNETs: Correlation with histopathological findings

PURPOSE

To compare CT and Texture features of liver metastases in Pancreatic Neuroendocrine Tumors (PNETs) and in Non-Pancreatic Neuroendocrine Tumors (NPNETs) according to tumor grading, overall survival (OS), time to progression (TTP) and Ki67 index.

METHODS

23 patients with PNETs and 25 patients with NPNETs affected by liver metastases were compared. The lesions were G1 and G2 according to WHO classification of tumors. Texture parameters (Mean, Standard Deviation, Entropy, Kurtosis, Skewness, Mean of Positive Pixel) at different spatial scale image filtration (SSF) were evaluated in both arterial and portal phase using a dedicated software for volumetric analysis. All CT images were acquired before the beginning of any medical treatment.

RESULTS

The following significant results (P < 0.05) were found: in the arterial phase for value of Skewness between PNETs G2 and NPNETs G2; in the portal phase between PNETs versus NPNETs, PNETs G1 versus NPNETs G1, PNETs G2 versus NPNETs G2; value of Mean in portal phase in PNETs vs NPNETs. Regarding PNETs, a P < 0.05 was found in: inverse correlation between Entropy and TTP; direct correlation between Mean and OS; correlating Kurtosis and high risk of death; correlating Skewness and low risk of death. Regarding NPNETs, P < 0.05 was found in: inverse correlation between Entropy and OS; correlating Entropy and high risk of dying.

CONCLUSIONS

This study shows that CT texture features are significantly different in PNETs from NPNETs. Additionally, textural features such as Entropy, Kurtosis and Skewness, were found to have significant correlation with higher mortality risk.

Residual tumor volume discriminates prognosis after surgery for neuroendocrine liver metastasis

BACKGROUND AND OBJECTIVES

We developed objective measurements of preoperative and residual tumor volume, and debulking rate, to evaluate their prognostic value for neuroendocrine liver metastasis (NELM).

METHODS

Seventy-three patients who underwent surgery for NELM were analyzed retrospectively. Indices of preoperative and postoperative residual tumor volume (pre-volume index [VI] and post-VI) were calculated as the sum of the cubes of individual tumor diameters on preoperative and postoperative imaging, respectively. The debulking rate (%) was calculated as 100 - 100 × post-VI/pre-VI. The classification and regression trees method was used to classify pre-VI and post-VI.

RESULTS

Overall survival (OS) was discriminated by preoperative tumor volume (5-year OS rates, 87.8% for low pre-VI and 60.1% for high pre-VI; P = .037) and residual tumor volume (5-year OS rates, 88.1% for low post-VI and 24.8% for high post-VI; P < .001). In contrast, debulking rates of 100%, ≥90%, and <90% did not discriminate OS (5-year OS rates, 88.0%, 61.9%, and 58.9%, respectively, not significant). In multivariate analysis, residual tumor volume (high post-VI, hazard ratio, 6.40; 95% confidence interval, 1.45-32.3) was an independent prognostic factor for OS.

CONCLUSIONS

Objective measurement of tumor volume demonstrates that residual tumor volume is prognostic after surgery for NELM.

Radiographic characteristics of neuroendocrine liver metastases do not predict clinical outcomes following liver resection

Background

Previous research has demonstrated that specific radiographic criteria, including the presence of calcifications and the enhancement pattern on computed tomography (CT) imaging, correlates with clinicopathologic features and outcomes of patients with gastroenteropancreatic neuroendocrine tumors (NET). We sought to investigate whether these radiographic characteristics were prognostic among patients with neuroendocrine liver metastases (NELM) undergoing surgical resection.

Methods

The preoperative contrast-enhanced CT scans of all patients who underwent resection of NELM at a single institution between 2000-2015 were retrospectively reviewed. The presence of calcifications was determined on non-contrast phase imaging. Enhancement on the arterial phase scan was categorized as hyperenhancing, hypoenhancing, or mixed. Relevant clinicopathologic characteristics as well as recurrence-free survival (RFS) and overall survival (OS) were compared between groups.

Results

Among 82 patients who underwent resection of NELM, 57 had available data on calcifications while 51 had data available on arterial enhancement patterns. Among all patients, median age was 58 (IQR: 47-63) and the majority were female (N=48, 59.5%). The most common primary tumor locations were pancreas (N=25, 30.5%) and small bowel (N=27, 32.9%). The most commonly performed operations were right hepatectomy (N=29, 35.4%), bisegmentectomy (N=15, 18.3%), and segmentectomy (N=14, 17.1%). Median tumor number was 4 (IQR: 2-9), median Ki-67 was 5% (IQR: 2-10%), and median size of the largest liver metastasis was 4.5 (IQR: 2.8-7.7) cm. Twelve (21%) patients had tumor calcifications. Among patients with and without calcifications there were no differences in demographics, clinicopathologic characteristics, RFS (P=0.772) or OS (P=0.095). Arterial enhancement was hypoenhancing in 23 (45.1%), hyperenhancing in 10 (19.6%), and mixed in 18 (35.3%). Similarly, there were no differences between arterial enhancement groups in demographics, clinicopathologic characteristics, RFS (P=0.618) or OS (P=0.268).

Conclusions

Radiographic characteristics on contrast-enhanced CT are not associated with the outcomes of patients undergoing resection of NELM. Future investigations should evaluate the prognostic impact of functional neuroendocrine imaging.

Prognostic impact of tumour burden in stage IV neuroendocrine neoplasia: A comparison between pancreatic and gastrointestinal localizations

BACKGROUND

Although prognosis of NENs is affected by several features including tumour burden, the specific role of this factor in pancreatic NENs (PanNENs) and gastrointestinal NENs (GI NENs) is not well established.

AIM

To compare the prognostic role of tumour burden in PanNENs and GI NENs.

PATIENTS AND METHODS

This study was a retrospective analysis of stage IV PanNENs and GI NENs. Tumours were classified based on liver tumour volume (<25% or >25%). Overall survival as assessed by Kaplan-Meier curves, and Cox proportional hazards method was used to perform risk factor analysis.

RESULTS

The analysis included 300 patients, including 166 panNENs (55.3%) and 134 GI NENs (44.7%). A total of 158 patients (52.7%) had G2 tumours, 107 had G1 tumours (35.7%), and 35 had G3 tumours (11.6%). Tumour liver involvement >25% was observed in 187 patients (62.3%): 106 PanNENs (56.7%), and 81 GI NENs (43.3%) (p = 0.551). Bone metastases were present in 45 patients (15%): 22 PanNENs (13.2%) and 23 GI NENs (17.1%) (p = 0.416). Characteristics of the PanNENs, including: grading (G2 vs G1, HR = 3.7; G3 vs G1, HR = 16.40), liver involvement > 25% (HR = 3.09), and bone metastases (HR = 2.27) were independent predictors for poor survival, whereas the only significant risk factor in GI NENs was grading (G2 vs G1, HR = 4.36; G3 vs G1, HR = 8.60).

CONCLUSIONS

PanNENs and GI NENs have different risk profiles. Liver tumour volume and the presence of bone metastases significantly affect survival in patients with PanNENs but has no impact on the clinical outcomes of GI NENs.

Early Prediction of Treatment Response of Neuroendocrine Hepatic Metastases after Peptide Receptor Radionuclide Therapy with 90Y-DOTATOC Using Diffusion Weighted and Dynamic Contrast-Enhanced MRI

The purpose of this study was to determine if parameters derived from diffusion-weighted (DW-) and dynamic contrast-enhanced (DCE-) magnetic resonance imaging (MRI) can help to assess early response to peptide receptor radionuclide therapy (PRRT) with ⁹⁰Y-DOTATOC in neuroendocrine hepatic metastases (NET-HM). Twenty patients (10 male; 10 female; mean age: 59.2 years) with NET-HM were prospectively enrolled in this single-center imaging study. DW-MRI and DCE-MRI studies were performed just before and 48 hours after therapy with ⁹⁰Y-DOTATOC. Abdominal SPECT/CT was performed 24 hours after therapy. This MRI imaging and therapy session was repeated after a mean interval of 10 weeks. Up to four lesions per patient were evaluated. Response to therapy was evaluated using metastasis sizes at the first and second therapy session as standard for comparison (regressive, stable, and progressive). DW-MRI analysis included the apparent diffusion coefficient (ADC) and parameters related to intravoxel incoherent motion (IVIM), namely, diffusion (D), perfusion fraction (f) and pseudo-diffusion (D ^∗ ). DCE-MRI analysis comprised K_trans, v _e and k _ep. For statistical analysis of group differences, one-way analysis of variance (ANOVA) and appropriate post hoc testing was performed. A total of 51 lesions were evaluated. Seven of 51 lesions (14%) showed size progression, 18/51 (35%) regression, and 26/51 (51%) remained stable. The lesion-to-spleen uptake ratio in SPECT showed a decrease between the two treatment sessions that was significantly stronger in regressive lesions compared with stable (p = 0.013) and progressive lesions (p = 0.021). ANOVA showed significant differences in mean ADC after 48 h (p = 0.026), with higher ADC values for regressive lesions. Regarding IVIM, highest values for D at baseline were seen in regressive lesions (p = 0.023). In DCE-MRI, a statistically significant increase in v _e after 10 weeks (p = 0.046) was found in regressive lesions. No differences were observed for the transfer constants K_trans and k _ep. Diffusion restriction quantified as ADC was able to differentiate regressive from progressive NET-HMs as early as 48 hours after PRRT. DW-MRI therefore may complement scintigraphy/SPECT for early assessment of response to PRRT. Assessment of perfusion parameters using IVIM and DCE-MRI did not show an additional benefit.

Management of Gastrointestinal Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are derived from neuroendocrine cell system and can have benign or malignant characteristics. They are rare tumors, but have been increasing in incidence over the past 40 years. Patients with NENs may develop symptoms due to primary tumor invasion, metastasis, or from secretion of hormonally active tumor substances. Multiple imaging modalities are used for diagnosis and staging, including specialty scans such as ¹¹¹In pentetreotide (Octreoscan) and ⁶⁸Gallium-DOTATATE, along with endoscopy, endoscopic ultrasound, and biochemical marker testing. Treatment involves both surgical approach, for both primary and metastatic lesions, as well as medical management for symptom management and disease progression. This article will review the current clinical knowledge regarding the diagnosis, treatment, and prognosis of these fascinating neoplasms and the associated hormonal syndromes.

Poorly differentiated neuroendocrine rectal carcinoma with uncommon immune-histochemical features and clinical presentation with a subcutaneous metastasis, treated with first line intensive triplet chemotherapy plus bevacizumab FIr-B/FOx regimen: an experience of multidisciplinary management in clinical practice

Background

Neuroendocrine tumors (NETs) are heterogeneous, widely distributed tumors arising from neuroendocrine cells. Gastrointestinal (GI)-NETs are the most common and NETs of the rectum represent 15, 2% of gastrointestinal malignancies. Poorly differentiated neuroendocrine carcinomas of the GI tract are uncommon. We report a rare case of poorly differentiated locally advanced rectal neuroendocrine carcinoma with nodal and a subcutaneous metastasis, with a cytoplasmic staining positive for Synaptophysin and Thyroid Transcription Factor-1.

Case presentation

A 72-year-old male presented to hospital, due to lumbar, abdominal, perineal pain, and severe constipation. A whole-body computed tomography scan showed a mass of the right lateral wall of the rectum, determining significant reduction of lumen caliber. It also showed a subcutaneous metastasis of the posterior abdominal wall. Patient underwent a multidisciplinary evaluation, diagnostic and therapeutic plan was shared and defined. The pathological examination of rectal biopsy and subcutaneous nodule revealed features consistent with small-cell poorly differentiated neuroendocrine carcinoma. First line medical treatment with triplet chemotherapy and bevacizumab, according to FIr-B/FOx intensive regimen, administered for the first time in this young elderly patient affected by metastatic rectal NEC was highly active and tolerable, as previously reported in metastatic colo-rectal carcinoma (MCRC). A consistent rapid improvement in clinical conditions were observed during treatment. After 6 cycles of treatment, CT scan and endoscopic evaluation showed clinical complete response of rectal mass and lymph nodes; patient underwent curative surgery confirming the pathologic complete response at PFS 9 months.

Discussion and conclusions

This case report of a locally advanced rectal NEC with an unusual subcutaneous metastasis deserves further investigation of triplet chemotherapy-based intensive regimens in metastatic GEP NEC.

Incidence and risk factors of gastrointestinal neuroendocrine neoplasm metastasis in liver, lung, bone, and brain: A population-based study

Background

Neuroendocrine neoplasm is a rare solid tumor. Metastatic pattern of the gastrointestinal neuroendocrine neoplasm (GI‐NEN) has not been fully explored.

Methods

Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database (SEER‐9 registry) from 1973 to 2015. Incidence was estimated by Joinpoint regression analyses. Data with additional treatment fields of GI‐NEN were extracted from the SEER‐18 registry from 1 January 2010 to 31 December 2015. A total of 14 685 GI‐NEN patients were included in this study. Statistical analyses were performed with SPSS 25.0, the Intercooled Stata SE 15.0, and GraphPad Prism 7.

Results

Incidence of GI‐NENs increased from 0.51 per 100 000 patients in 1973 to 6.20 per 100 000 patients in 2015. Of them, 2003 patients were stage IV GI‐NEN at the time of diagnosis, including 1459 (72.84%) patients with liver metastasis, 144 (7.19%) lung metastasis, 115 (5.74%) bone metastasis, and 27 (1.35%) brain metastasis. Esophageal NEN had the highest risk of metastasis (52.68%). The median survival for patients with liver, lung, bone, and brain metastasis was 38, 6, 9, and 2 months, respectively. The presence of lung or liver metastasis indicated higher risk of concurrent existence of bone and brain metastasis than those without.

Conclusion

Bone and brain metastasis should be screened in the GI‐NEN patients if they had lung or liver metastasis. Findings of the current study could help clinicians to identify distant metastasis of GI‐NENs as early as possible, and by which, to improve survival rate of GI‐NENs.

Current Practices and Novel Techniques in the Diagnosis and Management of Neuroendocrine Tumors of Unknown Primary

Neuroendocrine tumors (NETs) comprise a heterogeneous group of neoplasms in which tumor staging/prognosis and response to treatments depend heavily on accurate and timely identification of the anatomic primary site or NET subtype. Despite recent technological advancements and use of multiple diagnostic modalities, 10% to 14% of newly diagnosed NETs are not fully characterized based on subtype or anatomic primary site. Inability to fully characterize NETs of unknown primary may cause delays in surgical intervention and limit potential treatment options. To address this unmet need, clinical validity and utility are being demonstrated for novel approaches that improve NET subtype or anatomic primary site identification. Functional imaging using Ga-radiolabeled DOTATATE positron emission tomography/computed tomography has been shown to overcome some false-positive and resolution issues associated with octreotide scanning and computed tomography/magnetic resonance imaging. Using a genomic approach, molecular tumor classification based on differential gene expression has demonstrated high diagnostic accuracy in blinded validation studies of different NET types and subtypes. Given the widespread availability of these technologies, we propose an algorithm for the workup of NETs of unknown primary that integrates these approaches. Including these technologies in the standard workup will lead to better NET subtype identification and improved treatment optimization for patients.

PET/MRI for neuroendocrine tumors: a match made in heaven or just another hype?

Purpose

To evaluate the current literature on technical feasibility and diagnostic value of PET/MRI in management of patients with neuroendocrine tumors (NETs).

Methods

A systematic literature search of the PubMed/MEDLINE database identified studies that evaluated the role of simultaneous PET/MRI for the evaluation of neuroendocrine tumors in human subjects. Exclusion criteria included studies lacking simultaneous PET/MRI, absence of other than attenuation-correction MRI pulse sequences, and case reports. No data-pooling or statistical analysis was performed due to the small number of articles and heterogeneity of the methodologies.

Results

From the 21 identified articles, five were included, which demonstrated successful technical feasibility of simultaneous PET/MRI through various imaging protocols in a total of 105 patients. All articles demonstrated equal or superior detection of liver lesions by PET/MRI over PET/CT. While one study reported superior detection of bone lesions by PET/MRI, two demonstrated favorable detection by PET/CT. Two studies demonstrated superiority of PET/CT in detection of nodal metastases; three studies reported the pitfall of PET/MRI in detection of lung lesion.

Conclusion

The current literature reports successful technical feasibility of PET/MRI for imaging of NETs. While whole-body PET/CT in conjunction with an abdominal MRI may serve as a comprehensive approach for baseline staging, follow up with PET/MRI may be preferred for those with liver-only disease. Another possible role for PET/MRI is to provide a multiparametric approach to follow up of response to treatment. With further advances in MRI imaging acquisitions and post-processing techniques, PET/MRI may become more applicable to a broader group of patients with NETs, and possibly the imaging modality of choice for this patient population.

Bone Metastases in Neuroendocrine Neoplasms: From Pathogenesis to Clinical Management

Bone represents a common site of metastases for several solid tumors. However, the ability of neuroendocrine neoplasms (NENs) to localize to bone has always been considered a rare and late event. Thanks to the improvement of therapeutic options, which results in longer survival, and of imaging techniques, particularly after the introduction of positron emission tomography (PET) with gallium peptides, the diagnosis of bone metastases (BMs) in NENs is increasing. The onset of BMs can be associated with severe skeletal complications that impair the patient’s quality of life. Moreover, BMs negatively affect the prognosis of NEN patients, bringing out the lack of curative treatment options for advanced NENs. The current knowledge on BMs in gastro-entero-pancreatic (GEP) and bronchopulmonary (BP) NENs is still scant and is derived from a few retrospective studies and case reports. This review aims to perform a critical analysis of the evidence regarding the role of BMs in GEP- and BP-NENs, focusing on the molecular mechanisms underlining the development of BMs, as well as clinical presentation, diagnosis, and treatment of BMs, in an attempt to provide suggestions that can be used in clinical practice.

Salvage PRRT with 177Lu-DOTA-octreotate in extensively pretreated patients with metastatic neuroendocrine tumor (NET): dosimetry, toxicity, efficacy, and survival

Background

NETTER-1 trial demonstrated high efficacy and low toxicity of four cycles of Peptide Receptor Radionuclide Therapy (PRRT) in patients with metastasized NET. The present study evaluates the outcome of further PRRT cycles in the so called salvage setting in patients after initial response to four therapy cycles and later progression.

Methods

Thirty five patients (pat.) (25 male, 10 female, 63 ± 9 years) with progressive, metastasized NET (23 small intestinal, 5 lung, 4 CUP, 1 rectal, 1 gastric and 1 paraganglioma) were included. All patients previously received 4 PRRT cycles with ¹⁷⁷Lu-DOTATATE and showed initial response. SPECT based dosimetry was applied to determine kidney and tumor doses. Therapy response was evaluated using ⁶⁸Ga-DOTATATE PET/CT (with high dose CT), CT alone or MRI (RECIST 1.1), toxicity was defined using CTCAE 5.0 criteria. ^99mTc99-MAG3 scintigraphy was used to assess potential renal tubular damage. Progression free survival (PFS) and Overall survival (OS) analysis was performed with the Kaplan-Meier-method.

Results

The median PFS after initial PRRT was 33 months (95% CI: 30–36). The mean cumulative dose for including salvage PRRT was 44 GBq (range 33.5–47). One pat. (2.9%) showed grade 3 hematotoxicity. Kidney dosimetry revealed a mean cumulative kidney dose after a median of 6 PRRT cycles of 23.8 Gy. No grade 3 / 4 nephrotoxicity or relevant decrease in renal function was observed. Follow-up imaging was available in 32 patients after salvage therapy. Best response according to RECIST 1.1. was PR in one patient (3.1%), SD in 26 patients (81.3%) and PD in 5 patients (15.6%). PFS after salvage therapy was 6 months (95% CI: 0–16; 8 patients censored). Mean OS after initial PRRT was 105 months (95% CI: 92–119) and 51 months (95% CI: 41–61) after start of salvage therapy. Median OS was not reached within a follow-up of 71 months after initial PRRT and 25 months after start of salvage PRRT, respectively.

Conclusions

Salvage therapy with ¹⁷⁷Lu-DOTATATE is safe and effective even in patients with extensive previous multimodal therapies during disease progression and represents a feasible and valuable therapy option for progressive NET.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6000-y) contains supplementary material, which is available to authorized users.

Evaluation and Management of Neuroendocrine Tumors of the Pancreas

Pancreatic neuroendocrine tumors are a diverse group of neoplasms with a generally favorable prognosis. Although they exhibit indolent growth, metastases are seen in roughly 60% of patients. Pancreatic neuroendocrine tumors may produce a wide variety of hormones, which are associated with dramatic symptoms, but the majority are nonfunctional. The diagnosis and treatment of these tumors is a multidisciplinary effort, and management guidelines continue to evolve. This review provides a concise summary of the presentation, diagnosis, surgical management, and systemic treatment of pancreatic neuroendocrine tumors.

Radioembolisation with 90Y microspheres for neuroendocrine liver metastases: an institutional case series, systematic review and meta-analysis

BACKGROUND

Neuroendocrine liver metastases are clinically challenging due to their frequent disseminated distribution. This study aims to present a British experience with an emerging modality, radioembolisation with yttrium-90 labelled microspheres, and embed this within a meta-analysis of response and survival outcomes.

METHODS

A retrospective case series of patients treated with SIR-Spheres (radiolabelled resin microspheres) was performed. Results were included in a systematic review and meta-analysis of published results with glass or resin microspheres. Objective response rate (ORR) was defined as complete or partial response. Disease control rate (DCR) was defined as complete/partial response or stable disease.

RESULTS

Twenty-four patients were identified. ORR and DCR in the institutional series was 14/24 and 21/24 at 3 months. Overall survival and progression-free survival at 3-years was 77.6% and 50.4%, respectively. There were no grade 3/4 toxicities post-procedure. A fixed-effects pooled estimate of ORR of 51% (95% CI: 47%-54%) was identified from meta-analysis of 27 studies. The fixed-effects weighted average DCR was 88% (95% CI: 85%-90%, 27 studies).

CONCLUSION

Current data demonstrate evidence of the clinical effectiveness and safety of radioembolisation for neuroendocrine liver metastases. Prospective randomised studies to compare radioembolisation with other liver directed treatment modalities are needed.

Stage IV lung carcinoids: spectrum and evolution of proliferation rate, focusing on variants with elevated proliferation indices

The spectrum and evolution of proliferation rates in stage IV lung carcinoids is poorly defined. In particular, there are limited data on the prevalence and characteristics of tumors exceeding the standard upper proliferative criteria-as defined largely based on early-stage carcinoids-in metastatic setting. Sixty-six patients with stage IV lung carcinoids were identified, and all evaluable samples (n = 132; mean 2 samples per patient) were analyzed for mitotic counts and Ki-67 rate. Clinicopathologic and genomic features associated with elevated proliferation rates (>10 mitoses per 2 mm2 and/or >20% hot-spot Ki-67), and evolution of proliferation rates in serial specimens were analyzed. We found that mitoses and/or Ki-67 exceeded the standard criteria in 35 of 132 (27%) samples, primarily (31/35 cases) at  metastatic sites. Although neuroendocrine neoplasms with >10 mitoses per 2 mm2 are currently regarded as de facto neuroendocrine carcinomas, the notion that these cases are part of the spectrum of carcinoids was supported by (1) well-differentiated morphology, (2) conventional proliferation rates in other samples from same patient, (3) genetic characteristics, including the lack of RB1/TP53 alterations in all tested samples (n = 19), and (4) median overall survival of 2.7 years, compared to <1 year survival of stage IV neuroendocrine carcinomas in the historic cohorts. In patients with matched primary/metastatic specimens (48 pairs), escalation of mitoses or Ki-67 by ≥10 points was observed in 35% of metastatic samples; clonal relationship in one pair with marked proliferative progression was confirmed by next-generation sequencing. Notably, escalation of proliferation rate was documented in a subset of metastases arising from resected typical carcinoids, emphasizing that the diagnosis of typical carcinoid in primary tumor does not assure low proliferation rate at metastatic sites. In conclusion, stage IV lung carcinoids frequently exceed the standard proliferative criteria established for primary tumors, and commonly exhibit proliferative escalation at metastatic sites. Despite the overlap of proliferation rates, these tumors show fundamental morphologic, genomic and clinical differences from neuroendocrine carcinomas, and should be classified separately from those tumors. Awareness of the increased proliferative spectrum in metastatic carcinoids is critical for their accurate diagnosis. Further studies are warranted to explore the impact of proliferation indices on prognosis and therapeutic responses of patients with metastatic carcinoids.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) with liver metastases

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) is a rare pulmonary disorder characterised by classic radiological findings and symptoms of obstructive lung disease. DIPNECH is considered a precursor to carcinoid tumours in the lungs. In this case, we describe a patient with years of unexplained dry cough presenting with 2 weeks of progressive nausea and vomiting, and found to have massive hepatomegaly on examination. By CT-PE, she was diagnosed with DIPNECH, and abdominal MRI revealed metastatic carcinoid tumours. Despite its non-specific presentation, DIPNECH has characteristic radiological findings of mosaic attenuation with numerous pulmonary nodules. DIPNECH requires early identification and close surveillance to prevent progression to carcinoid tumours. Thus, it is critical for frontline providers to consider this diagnosis as part of their differential when other common causes of obstructive lung disease have been ruled out.

Effects of novel somatostatin-dopamine chimeric drugs in 2D and 3D cell culture models of neuroendocrine tumors

Control of symptoms related to hormonal hypersecretion by functioning neuroendocrine tumors (NETs) is challenging. New therapeutic options are required. Since novel in vitro tumor models seem to better mimic the tumor in vivo conditions, we aimed to study the effect of somatostatin and dopamine receptor agonists (octreotide and cabergoline, respectively) and novel somatostatin-dopamine chimeric multi-receptor drugs (BIM-065, BIM-23A760) using 2D (monolayer) and 3D (spheroids) cultures. Dose-response studies in 2D and 3D human pancreatic NET cell cultures (BON-1 and QGP-1) were performed under serum-containing and serum-deprived conditions. Cell proliferation, somatostatin and dopamine receptor expression (SSTs and D2R), apoptosis, lactate dehydrogenase, as well as serotonin and chromogranin A (CgA) release were assessed. The following results were obtained. 3D cultures of BON-1/QGP-1 allowed better cell survival than 2D cultures in serum-deprived conditions. SSTs and D2R mRNA levels were higher in the 3D model vs 2D model. Octreotide/cabergoline/BIM-065/BIM-23A760 treatment did not affect cell growth or spheroid size. In BON-1 2D-cultures, only BIM-23A760 significantly inhibited CgA release -this effect being more pronounced in 3D cultures. In BON-1 2D cultures, cabergoline/BIM-065/BIM-23A760 treatment decreased serotonin release (maximal effect up to 40%), being this effect again more potent in 3D cultures (up to 67% inhibition; with BIM-23A760 having the most potent effects). In QGP-1, cabergoline/BIM-065 treatment decreased serotonin release only in the 3D model. In conclusion, cultures of NET 3D spheroids represent a promising method for evaluating cell proliferation and secretion in NET cell-line models. Compared to 2D models, 3D models grow relatively serum independent. In 3D model, SST-D2R multi-receptor targeting drugs inhibit CgA and serotonin secretion, but not NET cell growth.

Semi-quantitative visual assessment of hepatic tumor burden can reliably predict survival in neuroendocrine liver metastases treated with transarterial chemoembolization

OBJECTIVES

To evaluate the accuracy and reproducibility of semi-quantitative visual assessment of hepatic tumor burden (HTB) on MRI and to investigate its prognostic value in predicting overall survival (OS) in neuroendocrine liver metastases (NELMs) treated with transarterial chemoembolization (TACE).

METHODS

Three independent readers blinded to the quantitative HTB measurement reviewed baseline MRI in 111 NELM patients treated with TACE. Readers visually assessed and semi-quantitatively categorized HTB using the European Neuroendocrine Tumor Society (ENETS) guidelines. Quantitative HTB measured by manual segmentation was used as the reference standard. Agreements between quantitative and semi-quantitative measurement of HTB, as well as intra- and inter-reader reproducibility, were evaluated using weighted kappa coefficient and intraclass correlation coefficient (ICC). Survival analysis included the Kaplan-Meier curves and Cox regression. Harrell C-index was calculated to evaluate the prognostic value of semi-quantitative HTB for predicting OS.

RESULTS

According to quantitative HTB, 41, 29, 25, and 16 patients were categorized into ≤ 10%, 11-25%, 26-50%, and > 50% groups, respectively. Agreements between quantitative and semi-quantitative measurement of HTB by each reader (weighted kappa, 0.82-0.96), intra-reader agreement (weighted kappa, 0.95), and inter-reader agreements (weighted kappa, 0.84-0.91; ICC, 0.98) were at least substantial to almost perfect. Semi-quantitative HTB was an independent prognostic factor in NELMs treated with TACE (multivariate Cox regression, p < 0.001), with prognostic value comparable to that of quantitative HTB (Harrell C-index, 0.735 for both semi-quantitative and quantitative HTB in multivariate regression).

CONCLUSION

Semi-quantitative visual assessment of HTB using MRI is accurate and reproducible and could reliably predict OS in NELMs treated with TACE.

KEY POINTS

• Semi-quantitative visual assessment of HTB using MR imaging is considerably accurate, reproducible, and efficient. • Visually assessed semi-quantitative HTB serves as an independent predictor of OS in NELMs treated with TACE.

The Pancreas as a Site of Metastasis or Second Primary in Patients with Small Bowel Neuroendocrine Tumors

BACKGROUND

The small bowel and pancreas are the most common primary sites of neuroendocrine tumors (NETs) giving rise to metastatic disease. Some patients with small bowel NETs (SBNETs) present with synchronous or metachronous pancreatic NETs (PNETs), and it is unclear whether these are separate primaries or metastases from one site to the other.

METHODS

A surgical NET database including patients undergoing operations for SBNETs or PNETs was reviewed. Patients with synchronous or metachronous tumors in both the small bowel and pancreas were identified, and available tissues from primary tumors and metastases were examined using a 4-gene quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) panel developed for evaluating NETs of unknown primary.

RESULTS

Of 338 patients undergoing exploration, 11 had NETs in both the small bowel and pancreas. Tissues from 11 small bowel tumors, 9 pancreatic tumors, and 10 metastases were analyzed. qPCR and IHC data revealed that three patients had separate SBNET and PNET primaries, and five patients had SBNETs that metastasized to the pancreas. Pancreatic tissue was unavailable in two patients, and qPCR and IHC gave discrepant results in one patient.

CONCLUSIONS

NETs in both the small bowel and pancreas were found in 3% of our patients. In nearly two-thirds of evaluable patients, the pancreatic tumor was a metastasis from the SBNET primary, while in the remaining one-third of patients it represented a separate primary. Determining the origin of these tumors can help guide the choice of systemic therapy and surgical management.

Pathologic differential diagnosis of metastatic carcinoma in the liver

The liver is one of the most common sites to which malignancies preferentially metastasize. Although a substantial number of liver malignancies are primary tumors, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, the metastasis of carcinomas to the liver is relatively common and frequently encountered in clinical settings. Representative carcinomas that frequently metastasize to the liver include colorectal carcinoma, breast carcinoma, neuroendocrine tumors, lung carcinoma, and gastric carcinoma. The diagnostic confirmation of suspected metastatic lesions in the liver is generally achieved through a histopathologic examination of biopsy tissues. Although morphology is the most important feature for a pathologic differential diagnosis of metastatic carcinomas, immunohistochemical studies facilitate the differentiation of metastatic carcinoma origins and subtypes. Useful immunohistochemical markers for the differential diagnosis of metastatic carcinomas in the liver include cytokeratins (CK7, CK19, and CK20), neuroendocrine markers (CD56, synaptophysin, and chromogranin A), and tissue-specific markers (CDX2, SATB2, TTF-1, GCDFP-15, mammaglobin, etc.). Here, we provide a brief review about the pathologic differential diagnosis of major metastatic carcinomas in the liver.

Circulating tumour cells and their association with bone metastases in patients with neuroendocrine tumours

Background

Bone metastases are associated with a worse outcome in patients with neuroendocrine tumours (NETs). Tumour overexpression of C-X-C chemokine receptor 4 (CXCR4) appears predictive of skeletal involvement. We investigated the role of circulating tumour cells (CTCs) and CXCR4 expression on CTCs as potential predictors of skeleton invasion.

Methods

Blood from patients with metastatic bronchial, midgut or pancreatic NET (pNET) was analysed by CellSearch. CXCR4 immunohistochemistry was performed on matched formalin-fixed paraffin-embedded (FFPE) samples.

Results

Two hundred and fifty-four patients were recruited with 121 midgut and 119 pNETs, of which 51 and 36% had detectable CTCs, respectively. Bone metastases were reported in 30% of midgut and 23% of pNET patients and were significantly associated with CTC presence (p = 0.003 and p < 0.0001). In a subgroup of 40 patients, 85% patients with CTCs had CTCs positive for CXCR4 expression. The proportion of CXCR4-positive CTCs in patients with bone metastases was 56% compared to 35% in those without (p = 0.18) it. Staining for CXCR4 on matched FFPE tissue showed a trend towards a correlation with CXCR4 expression on CTCs (p = 0.08).

Conclusions

CTC presence is associated with bone metastases in NETs. CXCR4 may be involved in CTC osteotropism and present a therapeutic target to reduce skeletal morbidity.

Large Cell Neuroendocrine Carcinoma of the Cervix with Sequential Metastasis to Different Sites: A Case Report

Neuroendocrine carcinoma of the cervix is rare, and prognosis is very poor. Because of its rarity, effective treatment of neuroendocrine carcinoma of the cervix has not been established. It has distinct patterns of metastasis, but can be successfully treated with radical surgery and platinum-based chemotherapy. We report a 50-year-old woman who was diagnosed with large cell neuroendocrine carcinoma of the cervix and underwent radical surgery followed by adjuvant chemoradiation therapy. She experienced recurrence several times and to different sites, with sequential metastasis to the lung, breast, and retroperitoneum, but nevertheless survived more than 5 years.

LP1 from Lentinula edodes C91-3 Induces Autophagy, Apoptosis and Reduces Metastasis in Human Gastric Cancer Cell Line SGC-7901

Present study aimed to elucidate the anticancer effect and the possible molecular mechanism underlying the action of Latcripin 1 (LP1), from the mushroom Lentinula edodes strain C91-3 against gastric cancer cell lines SGC-7901 and BGC-823. Cell viability was measured by Cell Counting Kit-8 (CCK-8); morphological changes were observed by phase contrast microscope; autophagy was determined by transmission electron microscope and fluorescence microscope. Apoptosis and cell cycle were assessed by flow cytometer; wound-healing, transwell migration and invasion assays were performed to investigate the effect of LP1 on gastric cancer cell's migration and invasion. Herein, we found that LP1 resulted in the induction of autophagy by the formation of autophagosomes and conversion of light chain 3 (LC3I into LC3II. LP1 up-regulated the expression level of autophagy-related gene (Atg7, Atg5, Atg12, Atg14) and Beclin1; increased and decreased the expression level of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) proteins respectively, along with the activation of Caspase-3. At lower-doses, LP1 have shown to arrest cells in the S phase of the cell cycle and decreased the expression level of matrix metalloproteinase MMP-2 and MMP-9. In addition, it has also been shown to regulate the phosphorylation of one of the most hampered gastric cancer pathway, that is, protein kinase B/mammalian target of rapamycin (Akt/mTOR) channel and resulted in cell death. These findings suggested LP1 as a potential natural anti-cancer agent, for exploring the gastric cancer therapies and as a contender for further in vitro and in vivo investigations.

Right Ventricular Outflow Obstruction Due to Metastatic Neuroendocrine Tumor

Neuroendocrine tumors (NETs) are rare malignant tumors that arise from neuroendocrine cells of the gastrointestinal tract and often metastasize to the liver, lung, and bone. Cardiac metastasis of NETs is uncommon. We report a patient with a past medical history of a neuroendocrine tumor of the left femur presenting with signs and symptoms of new onset heart failure. Transthoracic echocardiogram and cardiac magnetic resonance showed a large mass within the right ventricle causing right ventricular outflow obstruction. A positron emission tomographic/computed tomographic scan (PET-CT) revealed increased uptake of fluorodeoxyglucose (FDG) activity within the right ventricle consistent with metastasis. Cardiac biopsy of the right ventricular mass revealed metastatic nonfunctioning neuroendocrine tumor. In view of the fact that it was a tumor that caused the right ventricular obstruction, the patient was started on chemotherapy with improvement of symptoms. This case highlights that in patients with a history of neuroendocrine tumor presenting with heart failure, cardiac metastasis should be included in the differential.

Surgical Approaches to the Management of Neuroendocrine Liver Metastases

Surgical approaches to hepatic metastases occupy an important role in the management of patients with neuroendocrine neoplasms and may have curative or palliative intentions. Resection of hepatic disease with curative intent is the only modality offering potential cure for patients with liver metastases; however, only a minority of patients are eligible. Regardless of resection margin, disease recurrence almost invariably occurs and novel adjuvant/neoadjuvant therapies are mandated to be included within multimodal treatment concepts. Liver transplantation in meticulously selected patients may be associated with excellent outcomes, but unfortunately demands on donated organs limit the wider utilization of this approach.

Liver transplantation and multivisceral transplantation in the management of patients with advanced neuroendocrine tumours

Orthotopic liver transplantation (OLT) represents a generally accepted albeit somewhat controversially discussed therapeutic strategy in highly selected patients with non-resectable hepatic metastases from neuroendocrine tumours (NET). Whilst there are some exclusion criteria, these are not universally followed, and the optimal set of inclusion parameters for deeming patients eligible has not yet been elucidated. This is due to heterogeneity in the study populations, as well differing approaches employed and also divergences in selection criteria between centres. Recent data have suggested that OLT may represent the most efficacious approach in terms of overall and disease-free survival to the management of NET metastatic to the liver when conducted in accordance with the modified Milan criteria. Therefore, a consensus set of selection criteria requires definition to facilitate stringent and fair allocation of deceased-donor organs, as well as consideration for living-donor organs. In the context of classically non-resectable metastatic tumour bulk, multivisceral transplantation with or without the liver may also be indicated, yet experience is very limited. In this review, we discuss the diagnostic work-up of patients in whom the aforementioned transplantation approaches are being considered, critically analyse the published experience and also anticipate future developments in this field, including a discussion of immediate and longer-term research priorities.

Pattern and risk factors for distant metastases in gastrointestinal neuroendocrine neoplasms: a population-based study

An increased incidence of gastrointestinal neuroendocrine neoplasms (GI‐NENs) has been reported worldwide, and metastasis is the leading cause of GI‐NEN‐related death. Studies of different metastatic patterns in patients with different primary sites are limited. A population‐based retrospective cohort study was conducted with the Surveillance, Epidemiology, and End Results (SEER) database. Patients with a GI‐NEN diagnosis between 2010 and 2014 were included. All statistical analyses were performed using Intercooled Stata 12.0 software. There were 12,501 patients eligible for analysis. The metastatic status, primary sites, and histology types affected the patients’ overall survival. The liver was the most common metastasis site (65.21% of patients with metastases). Esophageal NENs had the highest risk of metastasis (49.35%), whereas appendiceal NENs had the lowest risk of metastasis (2.79%). Neuroendocrine carcinomas (NECs) were more likely to develop metastatic disease than were neuroendocrine tumors (NETs); 7.12% of patients with NET and 30.20% of patients with NEC developed metastatic disease. The metastatic patterns varied according to the different primary sites and histology types. NECs had a higher potential to develop extrahepatic metastasis at all primary sites than did NETs. Regarding the choice of treatment, surgical resection of primary lesions lowered the risk of tumor‐specific death (HR = 0.37, CI: 0.30–0.46, P < 0.01), but surgical resection of metastatic sites did not confer an extra survival benefit (HR = 0.82, CI: 0.63–1.06, P = 0.14). Different primary sites and histology types of GI‐NENs have different metastatic patterns and survival. This knowledge could help clinicians to identify patients who require extra surveillance, provide insight for future studies on the mechanisms of metastasis, and establish a prognostic prediction model.

Global burden of neuroendocrine tumors and changing incidence in Kentucky

Background

Neuroendocrine tumors (NETs) have a low incidence but relatively high prevalence. Over the last three decades, the incidence of NETs has risen 6-fold in the United States. We conducted an observational study to compare the incidence of NETs reported to the Kentucky Cancer Registry (KCR) versus that reported to Surveillance, Epidemiology, and End Results Program (SEER). We also provide a systematic review of the state of neuroendocrine tumors worldwide, and compare the available global and local published data.

Methods

KCR and SEER databases were queried for NET cases between 1995 and 2015. A detailed literature review of epidemiological data for various nations worldwide summarize epidemiological data from various countries.

Results

KCR recorded 6179 individuals with newly diagnosed NETs between 1995 and 2015. Between 1995-2012, the incidence of NETs in KCR increased from 3.1 to 7.1 per 100,000 cases, while it increased from 3.96 to 6.61 in the SEER database. The incidence rates in both KCR and SEER databases were linear. 90.57% were Caucasians with 54.74% females. 27.67% of the Kentucky population was from the Appalachian region. Patients aged 50-64 years had the highest prevalence (38%). Lung NET (30.60%) formed the bulk of cases, followed by small intestine (16.82%), rectum/anus (11.35%) and colon (9.71%).

Conclusions

NETs incidence between 1995 and 2015 show a linear increase in both KCR and SEER databases. Because of this increased incidence it is imperative for community oncologists to familiarize themselves with this entity, which until recently was under-studied and with few viable treatment options.

Vertebral metastases from neuroendocrine tumours: How to avoid false positives on 68Ga-DOTA-TOC PET using CT pattern analysis?

OBJECTIVES

To develop criteria to improve discrimination between vertebral metastases from neuroendocrine tumours (NETs) and benign bone lesions on PET combined with CT using DOTA-D-Phe¹-Tyr³-octreotide labelled with gallium-68 (⁶⁸Ga-DOTA-TOC).

METHODS

In 535 NET patients, ⁶⁸Ga-DOTA-TOC PET/CT examinations were reviewed retrospectively for vertebral CT lesions and/or PET foci. For each vertebral PET abnormality, appearance on CT, biological volume (BV), standardized uptake value (SUV_max) and ratios to those of reference organs were determined. All vertebral abnormalities were characterized as a metastasis, a typical vertebral haemangioma (VH) or other benign lesion.

RESULTS

In 79 patients (14.8 %), we found 107 metastases, 34 VHs and 31 other benign lesions in the spine. The optimal cut-off values to differentiate metastases from benign lesions were BV ≥0.72 cm³, SUVmax ≥2, SUVmax ratio to a reference vertebra ≥2.1, to liver ≥0.28 and to spleen ≥0.14. They corresponded to lesion-based ⁶⁸Ga-DOTA-TOC PET/CT sensitivity of 87 %, 98 %, 97 %, 99 % and 94 %, and specificity of 55 %, 100 %, 90 %, 97 %, 100 %, respectively.

CONCLUSIONS

The high sensitivity of ⁶⁸Ga-DOTA-TOC-PET/CT in detecting NET vertebral metastases was confirmed; this study showed that specificity could be improved by combining CT features and quantifying ⁶⁸Ga-DOTA-TOC uptake.

KEY POINTS

• Bone metastases in neuroendocrine tumours correlate with prognosis. • Benign bone lesions may mimic metastases on ⁶⁸ Ga-DOTA-TOC PET/CT imaging. • The specific polka-dot CT pattern may be missing in some vertebral haemangiomas. • Lesion atypical for haemangiomas can be better characterized by quantifying ⁶⁸ Ga-DOTA-TOC uptake.

Whole-Body 68Ga-DOTANOC PET/MRI Versus 68Ga-DOTANOC PET/CT in Patients With Neuroendocrine Tumors: A Prospective Study in 28 Patients

PURPOSE

The aim of this study was to assess the diagnostic performance of simultaneous whole-body Ga-DOTANOC PET/MRI compared with Ga-DOTANOC PET/CT for detection of distant metastatic disease in patients with well-differentiated neuroendocrine tumors (NETs).

METHODS

Patients with histologically proven, well-differentiated NET (G1 or G2) were included in this prospective, institutional review board-approved study. Patients underwent Ga-DOTANOC PET/CT and subsequent Ga-DOTANOC PET/MRI after a single tracer injection on the same day for staging or restaging purposes. Images were evaluated for the presence of NET lesions by 2 rater teams, each consisting of a nuclear medicine physician and a radiologist, in an observer-blinded fashion. Overall agreement, accuracy, sensitivity, and specificity, relative to a composite reference standard (consensus review including follow-up data), were calculated.

RESULTS

Between July 2014 and June 2016, 28 patients were enrolled. Overall agreement and accuracy between the 2 rater teams were 91.7% (95% confidence interval [CI], 87.5%-95.9%) and 97% (95% CI, 94.4%-99.6%) for PET/MRI and 92.3% (95% CI, 88.3%-96.3%) and 94.6% (95% CI, 91.2%-98.1%) for PET/CT, respectively (P = 1.00).Overall, PET/MRI reached 89.8% sensitivity (95% CI, 77.8%-96.6%) and 100% specificity (95% CI, 97%-100%); PET/CT showed 81.6% sensitivity (95% CI, 68%-91.2%) and 100% specificity (95% CI, 97%-100%) for the detection of metastatic disease in NETs.

CONCLUSIONS

Whole-body Ga-DOTANOC PET/MRI appears to be comparable to Ga-DOTANOC PET/CT for lesion detection in patients with well-differentiated NETs.

The place of liver transplantation in the treatment of hepatic metastases from neuroendocrine tumors: Pros and cons

Liver metastases occur in nearly half of NET patients (MNETs) and heavily affect prognosis, with 5-yr. OS around 19-38%. Although it is difficult to show outcome differences for available treatments, due to the long course of disease, surgery for MNETs remains the most effective option in terms of survival and symptom control. Since MNETs frequently present as an oligo-metastatic, liver-limited disease, unresectable in 80% of cases, liver transplantation (LT) has emerged as a potential curative treatment. Nevertheless, experience with LT for MNETs is limited and burdened by highly heterogeneous outcomes and significant recurrence rate, mostly explained by the variability of selection criteria. Several prognostic factors have been identified: extended surgery on primary tumor associated to LT, elderly patients, pancreatic primary (pNET), extensive liver involvement, poorly differentiated tumors, high Ki67 levels and short wait time to LT. A proper patients' selection based on these data (Milan NET criteria) allows a significant survival advantage over non-transplant strategies, with excellent outcomes in recent series (69-97.2% 5-yr. OS) as opposed to patients undergoing non-surgical treatments (34-50.9%). Evidence indicates LT as the best option for selected patients with MNETs. The use of organs for MNETs is therefore justified.

Diagnosis of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are relatively rare; however, the incidence has increased over the last few decades. They are classified as functional or non-functional tumors according to the presence of associated clinical symptoms. The majority are non-functional tumors. For classification and staging, the World Health Organization 2010 classification system is the most commonly accepted. Chromogranin A is the most sensitive marker but has insufficient specificity. In general, PNETs are hypervascular tumors, and multiphasic contrast-enhanced computed tomography is considered the first choice for imaging study. Multiphasic magnetic resonance imaging can detect PNETs smaller than 2 cm and small liver metastasis compared with other modalities. Somatostatin receptor scintigraphy is often used in cases where functional PNETs are suspected. Positron emission tomography (PET) scan with 18F-fluorodeoxyglucose cannot visualize PNETs, but PET with 68-Ga DOTATATE can. Endoscopic ultrasonography can characterize smaller PNETs using contrast and confirm histology through fine needle aspiration or biopsy. In this article, we review the characteristics of grading systems and diagnostic modalities commonly used for PNETs.

Osteotropism of neuroendocrine tumors: role of the CXCL12/ CXCR4 pathway in promoting EMT in vitro

Neuroendocrine tumors (NETs) metastasize to the skeleton in approximately 20% of patients. We have previously shown that the epithelial-mesenchymal transition (EMT) regulates the NET osteotropism and that CXCR4 overexpression predicts bone spreading. Here, we unravel the molecular mechanisms linking the activation of the CXCL12/CXCR4 axis to the bone colonization of NETs using cell lines representative of pancreatic (BON1, CM, QGP1), intestinal (CNDT 2.5), and bronchial origin (H727). By combining flow cytometry and ELISA, BON1, CM and QGP1 cells were defined as CXCR4^high/CXCL12^low, while H727 and CNDT 2.5 were CXCR4^low/CXCL12^high. CXCL12 was inert on cell proliferation, but significantly increased the in vitro osteotropism of CXCR4^high/CXCL12^low cells, as assessed by transwell assays with or without Matrigel membranes. In these cells, CXCL12 induced in vitro a marked EMT-like transcriptional shift with acquirement of a mesenchymal shape. The nuclei of CXCR4^high/CXCL12^low NET cells were typically enriched in non-phosphorylated CXCR4, particularly upon agonist stimulation. Silencing of CXCR4 via siRNA prevented the CXCL12-induced EMT in CXCR4^high/CXCL12^low NET cell lines resulting in the abrogation of both migration and transcriptional mesenchymal patterns. Our data suggest that CXCL12 conveys EMT-promoting signals in NET cells through CXCR4, which in turn regulates transcriptional, morphologic and functional modifications resulting in enhanced in vitro osteotropism of NET cells. Unique functions of CXCR4 may be segregated in relation to its subcellular localization and may acquire potential relevance in future in vivo studies.

Freezing Fort Knox: Mesenteric Carcinoid Cryoablation

BACKGROUND

Neuroendocrine malignancy is indolent, yet relentless in its propensity to metastasize to the liver, where it may cause bizarre paraneoplastic syndromes. The pathophysiologic mechanism behind this predilection for hepatic metastasis is twofold: the portal venous system drains the most likely primary sites for neuroendocrine tumors, and the relatively immunosuppressed environment within the hepatic parenchyma is permissive for tumor growth. The standard of care for patients with metastatic neuroendocrine tumor is surgical resection of at least 90% of the tumor burden.

METHODS

This report describes CT-guided percutaneous cryoablation of an inoperable mesenteric carcinoid tumor that had previously demonstrated hepatic metastases utilizing hydrodissection to safely and effectively prevent further metastasis while priming the immune system to eradicate this malignancy systemically.

RESULTS

CT-guided percutaneous cryoablation is minimally invasive, has intrinsic analgesic properties, and may contribute to sensitization of the immune system against tumor antigens.

CONCLUSION

Percutaneous cryoablation with hydrodissection can be used to target intraabdominal malignancy in poor surgical candidates. This procedure is safe, effective, and minimally invasive.