Future directions in the treatment of neuroendocrine tumors: consensus report of the National Cancer Institute Neuroendocrine Tumor clinical trials planning meeting

Outcome prediction of SSTR-RADS-3A and SSTR-RADS-3B lesions in patients with neuroendocrine tumors based on 68Ga-DOTATATE PET/MR

PURPOSE

Somatostatin receptor (SSTR)-targeted PET imaging has emerged as a common approach to evaluating those patients with well-differentiated neuroendocrine tumors (NETs). The SSTR reporting and data system (SSTR-RADS) version 1.0 provides a means of categorizing lesions from 1 to 5 according to the likelihood of NET involvement, with SSTR-RADS-3A (soft-tissue) and SSTR-RADS-3B (bone) lesions being those suggestive of but without definitive NET involvement. The goal of the present study was to assess the ability of 68Ga-DOTATATE PET/MR imaging data to predict outcomes for indeterminate SSTR-RADS-3A and 3B lesions.

METHODS

NET patients with indeterminate SSTR-RADS-3A or SSTR-RADS-3B lesions who underwent 68Ga-DOTATATE PET/MR imaging from April 2020 through August 2023 were retrospectively evaluated. All patients underwent follow-up through December 2023 (median, 17 months; (3-31 months)), with imaging follow-up or biopsy findings ultimately being used to classify lesions as malignant or benign. Lesion maximum standardized uptake value (SUVmax) along with minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) values were measured and assessed for correlations with outcomes on follow-up.

RESULTS

In total, 33 indeterminate SSTR-RADS-3 lesions from 22 patients (19 SSTR-RADS-3A and 14 SSTR-RADS-3B) were identified based upon baseline 68Ga-DOTATATE PET/MR findings. Over the course of follow-up, 16 of these lesions (48.5%) were found to exhibit true NET positivity, including 9 SSTR-RADS-3A and 7 SSTR-RADS-3B lesions. For SSTR-RADS-3A lymph nodes, a diameter larger than 0.7 cm and an ADCmin of 779 × 10-6mm2/s or lower were identified as being more likely to be associated with metastatic lesions. Significant differences in ADCmin and ADCmean were identified when comparing metastatic and non-metastatic SSTR-RADS-3B bone lesions (P < 0.05), with these parameters offering a high predictive ability (AUC = 0.94, AUC = 0.86).

CONCLUSION

Both diameter and ADCmin can aid in the accurate identification of the nature of lesions associated with SSTR-RADS-3A lymph nodes, whereas ADCmin and ADCmean values can inform the accurate interpretation of SSTR-RADS-3B bone lesions.

New horizon of radiopharmaceuticals in management of neuroendocrine tumors

Neuroendocrine neoplasms are rare and heterogenous group of tumors with varying degrees of clinical presentations and involvement of multiple organ systems in the body. In the modern clinical practice somatostatin receptor molecular imaging and targeted radioligand therapy plays a vital role in the diagnosis and management of the disease. Several new and promising radiotracers for NET imaging and theranostics, belonging to various groups and classes are being studied and investigated. This exponential growth of radiotracers poses concerns about the indication, clinical benefit, and safety profile of the agents. We discuss the basis behind these radiotracers clinical use, receptor targeting and intra and inter tumor heterogeneity. Furthermore, role of dual tracer imaging, combination therapy and potential applications of dosimetry in predicting treatment outcome and safety profile is reviewed. Individualized precision medicine with better tumor characterization, maximum therapeutic benefit and minimum toxicity is the way forward for future medicine.

Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

Recent advances in targeted therapy for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is a fatal disease with a 5-year survival rate of 8% and a median survival of 6 mo. In PDAC, several mutations in the genes are involved, with Kirsten rat sarcoma oncogene (90%), cyclin-dependent kinase inhibitor 2A (90%), and tumor suppressor 53 (75%–90%) being the most common. Mothers against decapentaplegic homolog 4 represents 50%. In addition, the self-preserving cancer stem cells, dense tumor microenvironment (fibrous accounting for 90% of the tumor volume), and suppressive and relatively depleted immune niche of PDAC are also constitutive and relevant elements of PDAC. Molecular targeted therapy is widely utilized and effective in several solid tumors. In PDAC, targeted therapy has been extensively evaluated; however, survival improvement of this aggressive disease using a targeted strategy has been minimal. There is currently only one United States Food and Drug Administration-approved targeted therapy for PDAC – erlotinib, but the absolute benefit of erlotinib in combination with gemcitabine is also minimal (2 wk). In this review, we summarize current targeted therapies and clinical trials targeting dysregulated signaling pathways and components of the PDAC oncogenic process, analyze possible reasons for the lack of positive results in clinical trials, and suggest ways to improve them. We also discuss emerging trends in targeted therapies for PDAC: combining targeted inhibitors of multiple pathways. The PubMed database and National Center for Biotechnology Information clinical trial website (www.clinicaltrials.gov) were queried to identify completed and published (PubMed) and ongoing (clinicaltrials.gov) clinical trials (from 2003-2022) using the keywords pancreatic cancer and targeted therapy. The PubMed database was also queried to search for information about the pathogenesis and molecular pathways of pancreatic cancer using the keywords pancreatic cancer and molecular pathways.

Safety and Therapeutic Optimization of Lutetium-177 Based Radiopharmaceuticals

Peptide receptor radionuclide therapy (PRRT) using Lutetium-177 (¹⁷⁷Lu) based radiopharmaceuticals has emerged as a therapeutic area in the field of nuclear medicine and oncology, allowing for personalized medicine. Since the first market authorization in 2018 of [¹⁷⁷Lu]Lu-DOTATATE (Lutathera®) targeting somatostatin receptor type 2 in the treatment of gastroenteropancreatic neuroendocrine tumors, intensive research has led to transfer innovative ¹⁷⁷Lu containing pharmaceuticals to the clinic. Recently, a second market authorization in the field was obtained for [¹⁷⁷Lu]Lu-PSMA-617 (Pluvicto®) in the treatment of prostate cancer. The efficacy of ¹⁷⁷Lu radiopharmaceuticals are now quite well-reported and data on the safety and management of patients are needed. This review will focus on several clinically tested and reported tailored approaches to enhance the risk-benefit trade-off of radioligand therapy. The aim is to help clinicians and nuclear medicine staff set up safe and optimized procedures using the approved ¹⁷⁷Lu based radiopharmaceuticals.

Neuroendocrine Tumors: Genomics and Molecular Biomarkers with a Focus on Metastatic Disease

Neuroendocrine tumors (NETs) are considered rare tumors that originate from specialized endocrine cells. Patients often present with metastatic disease at the time of diagnosis, which negatively impacts their quality of life and overall survival. An understanding of the genetic mutations that drive these tumors and the biomarkers used to detect new NET cases is important to identify patients at an earlier disease stage. Elevations in CgA, synaptophysin, and 5-HIAA are most commonly used to identify NETs and assess prognosis; however, new advances in whole genome sequencing and multigenomic blood assays have allowed for a greater understanding of the drivers of NETs and more sensitive and specific tests to diagnose tumors and assess disease response. Treating NET liver metastases is important in managing hormonal or carcinoid symptoms and is imperative to improve patient survival. Treatment for liver-dominant disease is varied; delineating biomarkers that may predict response will allow for better patient stratification.

Evolving landscape of clinical trials in gastroenteropancreatic neuroendocrine neoplasms in the past two decades

BACKGROUND

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are heterogenous malignancies that require well-designed trials to develop effective management strategies. This cross-sectional study aimed to illustrate the current landscape of clinical trials in GEP-NENs to provide insights for future research.

MATERIALS AND METHODS

We reviewed all clinical trials registered on ClinicalTrials.gov between 1 January 2000 and 31 December 2021 with GEP-NEN in the 'condition or disease' field.

RESULTS

We included 206 eligible trials. Most trials enrolled less than 50 patients (59.8%) and were sponsored by institutions other than government or industry (67.0%). Most trials were conducted in high-income countries (86.6%) and countries located in Europe (30.1%) or Northern America (29.6%). The overall result reporting rates of GEP-NEN trials was 41.4%, and the median time from primary completion to result reporting was 101 months. Characteristics that improved the reporting of results included larger sample size, tumor differentiation specification for inclusion, progression-free survival as primary endpoint, industry sponsorship, and multicenter or multinational participation (all P < 0.05). Compared with trials registered between 2000 and 2011 (n = 28), trials registered between 2012 and 2021 (n = 178) were more likely to specify the Ki-67 index for inclusion (68.0% vs 35.7%, P = 0.002) and to be conducted outside Europe or Northern America (16.4% vs 3.7%, P = 0.02), while the sample size and the sponsorship did not change significantly.

CONCLUSIONS

Novel management options have been explored for GEP-NENs with more specific inclusion criteria during the past two decades. More efforts are needed to promote international collaborations in clinical trials and enhance timely result dissemination.

Bevacizumab plus FOLFIRI after failure of platinum-etoposide first-line chemotherapy in patients with advanced neuroendocrine carcinoma (PRODIGE 41-BEVANEC): a randomised, multicentre, non-comparative, open-label, phase 2 trial

BACKGROUND

There is no standard second-line treatment after platinum-etoposide chemotherapy for gastroenteropancreatic neuroendocrine carcinoma. We aimed to evaluate the efficacy of FOLFIRI plus bevacizumab, and FOLFIRI alone, in this setting.

METHODS

We did a randomised, non-comparative, open-label, phase 2 trial (PRODIGE 41-BEVANEC) at 26 hospitals in France. We included patients aged 18 years or older with locally advanced or metastatic gastroenteropancreatic neuroendocrine carcinoma or neuroendocrine carcinoma of unknown primary origin, documented progressive disease during or after first-line platinum-etoposide chemotherapy, and an Eastern Cooperative Oncology Group performance status of 0-2. Patients were randomly assigned (1:1; block size of three), without stratification, to receive FOLFIRI (irinotecan 180 mg/m², calcium folinate 400 mg/m² or levofolinate 200 mg/m², and fluorouracil 400 mg/m² bolus then 2400 mg/m² over 46 h) plus bevacizumab 5 mg/kg or FOLFIRI alone, intravenously, every 2 weeks until disease progression or unacceptable toxicity. Neither patients nor investigators were masked to group assignment. The primary outcome was overall survival at 6 months after randomisation, evaluated in the modified intention-to-treat population (all enrolled and randomly assigned patients who received at least one cycle of FOLFIRI). This study is now complete and is registered with ClinicalTrials.gov, NCT02820857.

FINDINGS

Between Sept 5, 2017, and Feb 8, 2022, 150 patients were assessed for eligibility and 133 were enrolled and randomly assigned: 65 to the FOLFIRI plus bevacizumab group and 68 to the FOLFIRI group. 126 patients (59 in the FOLFIRI plus bevacizumab group and 67 in the FOLFIRI group) received at least one cycle of FOLFIRI and were included in the modified intention-to-treat population, 83 (66%) of whom were male and 43 (34%) were female, and the median age of the patients was 67 years (IQR 58-73). The primary tumour location was colorectal in 38 (30%) of 126 patients, pancreatic in 34 (27%), gastro-oesophageal in 22 (17%), and unknown in 23 (18%). After a median follow-up of 25·7 months (95% CI 22·0-38·2), 6-month overall survival was 53% (80% CI 43-61) in the FOLFIRI plus bevacizumab group and 60% (51-68) in the FOLFIRI group. Grade 3-4 adverse events that occurred in at least 5% of patients were neutropenia (eight [14%] patients), diarrhoea (six [10%]), and asthenia (five [8%]) in the FOLFIRI plus bevacizumab group, and neutropenia (seven [10%]) in the FOLFIRI group. One treatment-related death (ischaemic stroke) occurred in the FOLFIRI plus bevacizumab group.

INTERPRETATION

The addition of bevacizumab did not seem to increase the benefit of FOLFIRI with regard to overall survival. FOLFIRI could be considered as a standard second-line treatment in patients with gastroenteropancreatic neuroendocrine carcinoma.

FUNDING

French Ministry of Health and Roche SAS.

Randomized Study of Temozolomide or Temozolomide and Capecitabine in Patients With Advanced Pancreatic Neuroendocrine Tumors (ECOG-ACRIN E2211)

PURPOSE

Patients with advanced pancreatic neuroendocrine tumors (NETs) have few treatment options that yield objective responses. Retrospective and small prospective studies suggest that capecitabine and temozolomide are associated with high response rates (RRs) and long progression-free survival (PFS).

PATIENTS AND METHODS

E2211 was a multicenter, randomized, phase II trial comparing temozolomide versus capecitabine/temozolomide in patients with advanced low-grade or intermediate-grade pancreatic NETs. Key eligibility criteria included progression within the preceding 12 months and no prior temozolomide, dimethyl-triazeno-imidazole-carboxamide or dacarbazine, capecitabine or fluorouracil. The primary end point was PFS; secondary endpoints were overall survival, RR, safety, and methylguanine methyltransferase (MGMT) by immunohistochemistry and promoter methylation.

RESULTS

A total of 144 patients were enrolled between April 2013 and March 2016 to temozolomide (n = 72) or capecitabine and temozolomide (n = 72); the primary analysis population included 133 eligible patients. At the scheduled interim analysis in January 2018, the median PFS was 14.4 months for temozolomide versus 22.7 months for capecitabine/temozolomide (hazard ratio = 0.58), which was sufficient to reject the null hypothesis for the primary end point (stratified log-rank P = .022). In the final analysis (May 2021), the median overall survival was 53.8 months for temozolomide and 58.7 months for capecitabine/temozolomide (hazard ratio = 0.82, P = .42). MGMT deficiency was associated with response.

CONCLUSION

The combination of capecitabine/temozolomide was associated with a significant improvement in PFS compared with temozolomide alone in patients with advanced pancreatic NETs. The median PFS and RR observed with capecitabine/temozolomide are the highest reported in a randomized study for pancreatic NETs. MGMT deficiency was associated with response, and although routine MGMT testing is not recommended, it can be considered for select patients in need of objective response (ClinicalTrials.gov identifier: NCT01824875).

Alpha-peptide receptor radionuclide therapy using actinium-225 labeled somatostatin receptor agonists and antagonists

Peptide receptor radionuclide therapy (PRRT) has over the last two decades emerged as a very promising approach to treat neuroendocrine tumors (NETs) with rapidly expanding clinical applications. By chelating a radiometal to a somatostatin receptor (SSTR) ligand, radiation can be delivered to cancer cells with high precision. Unlike conventional external beam radiotherapy, PRRT utilizes primarily β or α radiation derived from nuclear decay, which causes damage to cancer cells in the immediate proximity by irreversible direct or indirect ionization of the cells' DNA, which induces apoptosis. In addition, to avoid damage to surrounding normal cells, PRRT privileges the use of radionuclides that have little penetrating and more energetic (and thus more ionizing) radiations. To date, the most frequently radioisotopes are β^- emitters, particularly Yttrium-90 (⁹⁰Y) and Lutetium-177 (¹⁷⁷Lu), labeled SSTR agonists. Current development of SSTR-targeting is triggering the shift from using SSTR agonists to antagonists for PRRT. Furthermore, targeted α-particle therapy (TAT), has attracted special attention for the treatment of tumors and offers an improved therapeutic option for patients resistant to conventional treatments or even beta-irradiation treatment. Due to its short range and high linear energy transfer (LET), α-particles significantly damage the targeted cancer cells while causing minimal cytotoxicity toward surrounding normal tissue. Actinium-225 (²²⁵Ac) has been developed into potent targeting drug constructs including somatostatin-receptor-based radiopharmaceuticals and is in early clinical use against multiple neuroendocrine tumor types. In this article, we give a review of preclinical and clinical applications of ²²⁵Ac-PRRT in NETs, discuss the strengths and challenges of ²²⁵Ac complexes being used in PRRT; and envision the prospect of ²²⁵Ac-PRRT as a future alternative in the treatment of NETs.

Diagnosis and management of gastroenteropancreatic neuroendocrine neoplasms by nuclear medicine: Update and future perspective

Gastrointestinal (GI) cancers are the second most common cause of cancer related deaths in the World. Neuroendocrine neoplasms (NENs) is a rare tumor that originated from peptidergic neurons and neuroendocrine cells. NENs occurs in all parts of the body, especially in stomach, intestine, pancreas and lung. These rare tumors are challenging to diagnose at earlier stages because of their wide anatomical distribution and complex clinical features. Traditional imaging methods including magnetic resonance imaging (MRI) and computed tomography (CT) are mostly of useful for detection of larger primary tumors that are 1cm in size. A new medical imaging specialty called nuclear medicine uses radioactive substances for both diagnostic and therapeutic purposes. Nuclear medicine imaging relies on the tissue-specific uptake of radiolabeled tracers. Nuclear medicine techniques can easily identify the NENs tissues for their ability to absorb and concentrate amine, precursors, and peptides, whereas the traditional imaging methods are difficult to perform well. The somatostatin receptor (SSTR) is a targetable receptor frequently expressed in the gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), and is a promising target for tumor-targeted therapies and radiography. SSTR based somatostatin receptor imaging and peptide receptor radionuclide therapy (PRRT) has emerged as a new hot subject in the diagnosis and treatment of GEP-NENs due to the rapid development of somatostatin analogues (SSAs) and radionuclide. This review aims to provide an overview of the current status of nuclear medicine imaging modalities in the imaging of GEP-NENs, and puts them in perspective of clinical practice.

Long-term outcomes of resection versus transplantation for neuroendocrine liver metastases meeting the Milan criteria

Liver resection (LR) is considered the treatment of choice for resectable neuroendocrine liver metastases (NELM), while liver transplantation (LT) is currently reserved for highly selected unresectable patients. We retrospectively analyzed data from consecutive patients undergoing either curative resection or transplantation for liver-only NELM meeting Milan criteria at a single center between 1984 and 2019. Patients who fit Milan criteria were 48 in the transplantation group and 56 in the resection group. After a median follow-up of 158 months for the transplantation group and 126 for the resection group, the 10-year survival rate was 93% for transplantation and 75% for resection (p = .007). The 10-year disease-free survival rate was 52% for transplantation and 18% for resection (p < .001). Transplantation was associated with improved survival at univariate analysis. The median disease-free interval between surgery and recurrence was 78 months for transplantation vs. 24 months for resection (p < .001). The transplantation group had more multisite recurrences (12/25, 48% vs. 5/42, 12% in the resection group, p = .001), while most recurrences in the resection group were intra-hepatic (37/42, 88%, versus 2/25, 8% in the transplantation group). In conclusion, LT was associated with improved survival outcomes in NELM meeting the Milan criteria compared with LR.

International trends in pulmonary neuroendocrine cancer studies:a scientometric study

INTRODUCTION

Pulmonary neuroendocrine tumors account for approximately 20% of all primary lung tumors. Few studies summarize the current body of pulmonary neuroendocrine tumors studies worldwide.

OBJECTIVE

A quantitative scientometric analysis was conducted to evaluate the development of applications and innovations and to analyze their contribution to various areas of improvement in treatment and diagnosis of pulmonary neuroendocrine tumors.

METHODS

We searched for studies published in the last 20 years in the databases United States National Library of Medicine (PubMed), Scientific Electronic Library Online (SciELO), Scopus, and Web of Science, using the terms 'pulmonary neuroendocrine tumors', 'bronchial neuroendocrine tumors', 'bronchial carcinoid tumors', 'pulmonary carcinoid', 'typical pulmonary carcinoid', 'atypical pulmonary carcinoid', 'pulmonary carcinoid and diagnosis', 'pulmonary carcinoid and treatment', 'pulmonary carcinoid and epidemiology' and 'pulmonary carcinoid and prognosis'.

RESULTS

Our results showed the number of publications increased significantly over the study period and was strongly associated with the economic or financial situation of the publications' countries of origin. We observed a predominance of studies on histological diagnosis compared to treatment, and among the studies related to treatment, a predominance of retrospective studies relative to prospective studies was found.

CONCLUSION

Based on the published literature, we concluded research on pulmonary neuroendocrine tumors still seems to be incipient, because it favors studies related to histological characterization of the disease, and therapeutic studies are still predominantly of a retrospective nature.

Lanreotide Depot to Treat Gastroenteropancreatic Neuroendocrine Tumors in a US Community Oncology Setting: A Prospective, Observational Study

INTRODUCTION

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can result in symptoms such as diarrhea, flushing, abdominal pain, and fatigue and are often associated with a significant disease burden and poor prognosis. This non-interventional, prospective, observational study evaluated the real-world safety and effectiveness of lanreotide depot, a somatostatin analog (SSA) used to treat GEP-NETs, in a community setting.

METHODS

In this prospective, non-interventional study (NCT02730104), adult patients with locally advanced (inoperable), metastatic GEP-NETs treated with lanreotide depot were evaluated by their physician every 6 months from enrollment for 24 months. Clinically defined time to disease progression (TTDP) and overall survival (OS) were estimated for the total population and by primary tumor type (gastrointestinal [GI], pancreatic, unknown origin), and an exploratory analysis determined the rate of progression-free survival (PFS) at 12 and 24 months. Patient satisfaction was evaluated via the Treatment Satisfaction Questionnaire for Medication (TSQM-9), and safety information was recorded.

RESULTS

Of 99 patients, the 24-month PFS rate was 73.7% (95% confidence interval [CI] 63.1-81.7) and 24-month OS rate was 84.2% (95% CI 74.0-90.7). Median TTDP was not reached because few patients experienced disease progression during the study period. The majority of responding patients expressed satisfaction with treatment on each domain of the TSQM-9. Treatment-related adverse events (AEs) occurred in 19.2% of patients, while no serious AEs (SAEs) were related to the study drug.

CONCLUSIONS

Lanreotide depot is an effective and well-tolerated treatment for GEP-NETs in the real-world community setting.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02730104.

Apparent diffusion coefficients (ADC) in response assessment of transarterial radioembolization (TARE) for liver metastases of neuroendocrine tumors (NET): a feasibility study

Background

In patients with hepatic neuroendocrine tumors (NETs) locoregional therapies such as transarterial radioembolization (TARE) are increasingly applied. Response evaluation remains challenging and previous studies assessing response with diffusion-weighted imaging (DWI) have been inconclusive.

Purpose

To perform a feasibility study to evaluate if response assessment with quantitative apparent diffusion coefficient (ADC) in patients with liver metastases of NETs after TARE will be possible.

Material and Methods

Retrospectively, 43 patients with 120 target lesions who obtained abdominal magnetic resonance imaging (MRI) with DWI 39±28 days before and 74±46 days after TARE were included. Intralesional ADC (ADC_min, ADC_max, and ADC_mean) were measured for a maximum number of three lesions per patient on baseline and post-interventional DWI. Tumor response was categorized according to RECIST 1.1 and mRECIST.

Results

TARE resulted in partial remission (PR) in 23% (63%), in stable disease (SD) in 73% (23%), in progressive disease (PD) in 5% (7%) and in complete response (CR) in 0% (1%) according to RECIST 1.1 (mRECIST, respectively). ADC values increased significantly (P<0.005) after TARE in the PR group whereas there was no significant change in the PD group. Post-therapeutic ADC values of SD lesions increased significantly when evaluated by RECIST 1.1 but not if evaluated by mRECIST. Percentual changes of ADC_mean values were slightly higher for responders compared to non-responders (P<0.05).

Conclusion

ADC values seem to represent an additional marker for treatment response evaluation after TARE in patients with secondary hepatic NET. A conclusive study seems feasible though patient-based evaluation and overall survival and progression free survival as alternate primary endpoints should be considered.

CT-based radiomics for prediction of therapeutic response to Everolimus in metastatic neuroendocrine tumors

Aim

To test radiomic approach in patients with metastatic neuroendocrine tumors (NETs) treated with Everolimus, with the aim to predict progression-free survival (PFS) and death.

Materials and methods

Twenty-five patients with metastatic neuroendocrine tumors, 15/25 pancreatic (60%), 9/25 ileal (36%), 1/25 lung (4%), were retrospectively enrolled between August 2013 and December 2020. All patients underwent contrast-enhanced CT before starting Everolimus, histological diagnosis, tumor grading, PFS, overall survival (OS), death, and clinical data collected. Population was divided into two groups: responders (PFS ≤ 11 months) and non-responders (PFS > 11 months). 3D segmentation was performed on whole liver of naïve CT scans in arterial and venous phases, using a dedicated software (3DSlicer v4.10.2). A total of 107 radiomic features were extracted and compared between two groups (T test or Mann–Whitney), radiomics performance assessed with receiver operating characteristic curve, Kaplan–Meyer curves used for survival analysis, univariate and multivariate logistic regression performed to predict death, and interobserver variability assessed. All significant radiomic comparisons were validated by using a synthetic external cohort. P < 0.05 is considered significant.

Results

15/25 patients were classified as responders (median PFS 25 months and OS 29 months) and 10/25 as non-responders (median PFS 4.5 months and OS 23 months). Among radiomic parameters, Correlation and Imc1 showed significant differences between two groups (P < 0.05) with the best performance (internal cohort AUC 0.86–0.84, P < 0.0001; external cohort AUC 0.84–0.90; P < 0.0001). Correlation < 0.21 resulted correlated with death at Kaplan–Meyer analysis (P = 0.02). Univariate analysis showed three radiomic features independently correlated with death, and in multivariate analysis radiomic model showed good performance with AUC 0.87, sensitivity 100%, and specificity 66.7%. Three features achieved 0.77 ≤ ICC < 0.83 and one ICC = 0.92.

Conclusions

In patients affected by metastatic NETs eligible for Everolimus treatment, radiomics could be used as imaging biomarker able to predict PFS and death.

Perioperative Carcinoid Crisis: A Systematic Review and Meta-Analysis

Simple Summary

Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication for patients with neuroendocrine tumors (NET). Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting the use of perioperative octreotide to prevent CC. The aim of our meta-analysis was to evaluate the existing evidence characterizing CC and the efficacy of prophylactic octreotide. We found that CC occurs frequently in patients having midgut NETs surgery, specifically those with NET liver metastasis, and is associated with worse postoperative outcomes. Our findings did not show a decreased risk in CC with prophylactic octreotide and questioned the advantage of routine prophylactic octreotide.

Abstract

Background: Surgery is the only curative option for patients with neuroendocrine tumors (NET) and is also indicated for debulking of liver metastasis. Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication. Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting its use. We sought to evaluate existing evidence characterizing CC and evaluating the efficacy of prophylactic octreotide. Methods: A systematic review was performed on studies including patients having surgery for well-differentiated NET and/or NET liver metastasis (2000–2021), and reporting data on the incidence, risk factors, or prognosis of CC, and/or use of prophylactic octreotide. Meta-analysis was performed using random-effects models. Results: Eight studies met inclusion criteria (n = 943 operations). The pooled incidence of CC was 19% (95% CI [0.06–0.36]). Liver metastasis (odds ratio 2.85 [1.49–5.47]) and gender (male 0.58 [0.34–0.99]) were the only significant risk factors. The occurrence of CC was associated with increased risk of major postoperative complications (2.12 [1.03–4.35]). The use of prophylactic octreotide was not associated with decreased risk of CC (0.73 [0.32–1.66]). Notably, there was no standard prophylactic octreotide strategy used. Conclusions: Intraoperative carcinoid crisis is a common complication occurring in up to 20% of patients with midgut NET and/or liver metastasis undergoing surgery. Prophylactic octreotide may not provide an efficient way to prevent this complication. Future studies should focus on prospective evaluation of well-defined prophylactic protocols using a standardized definition for CC.

Early Complications of Radioisotope Therapy with Lutetium-177 and Yttrium-90 in Patients with Neuroendocrine Neoplasms-A Preliminary Study

Neuroendocrine neoplasms (NENs) constitute a heterogenous group of tumors originating from neuroendocrine cells scattered throughout the body. Peptide Receptor Radionuclide Therapy (PRRT) is a treatment of choice of unresectable metastasized progressive and well-differentiated NENs. The aim of the study was to assess early bone marrow and kidney injury after administration of Lutetium-177 or Lutetium-177 combined with Yttrium-90. Thirty-one patients received treatment with [¹⁷⁷Lu]Lu-DOTATATE with the activity of 7.4 GBq. Eleven patients received tandem treatment with [⁹⁰Y]Y-DOTATATE with the activity of 1.85 GBq + [¹⁷⁷Lu]Lu-DOTATATE with the activity of 1.85 GBq. After PRRT a significant decrease in leukocyte, neutrophil, and lymphocyte counts was noted. Tandem treatment demonstrated a more marked decrease in white blood cell count compared to Lutetium-177 therapy only. Conversely, no significant influence on glomerular filtration was found in this assessment. However, PRRT triggered acute renal tubule dysfunction, regardless of the treatment type. Regarding the acute complications, PRRT appeared to be a safe modality in the treatment of patients with NEN.

Perspectives on the diagnostic, predictive and prognostic markers of neuroendocrine neoplasms (Review)

Neuroendocrine neoplasms (NENs) are a heterogeneous group of rare tumors with different types of physiology and prognosis. Therefore, prognostic information, including morphological differentiation, grade, tumor stage and primary location, are invaluable and contribute to the formulation of treatment decisions. Biomarkers that are currently used, including chromogranin A (CgA), serotonin and neuron-specific enolase, are singular parameters that cannot be used to accurately predict variables associated with tumor growth, including proliferation, metabolic rate and metastatic potential. In addition, site-specific biomarkers, such as insulin and gastrin, cannot be applied to all types of NENs. The clinical application of broad-spectrum markers, as it is the case for CgA, remains controversial despite being widely used. Due to limitations of the currently available mono-analyte biomarkers, recent studies were conducted to explore novel parameters for NEN diagnosis, prognosis, therapy stratification and evaluation of treatment response. Identification of prognostic factors for predicting NEN outcome is a critical requirement for the planning of adequate clinical management. Advances in ‘liquid’ biopsies and genomic analysis techniques, including microRNA, circulating tumor DNA or circulating tumor cells and sophisticated biomathematical analysis techniques, such as NETest or molecular image-based biomarkers, are currently under investigation as potentially novel tools for the management of NENs in the future. Despite these recent findings yielding promising observations, further research is necessary. The present review therefore summarizes the existing knowledge and recent advancements in the exploration of biochemical markers for NENs, with focus on gastroenteropancreatic-neuroendocrine tumors.

Epigenetic-based targeted therapies for well-differentiated pancreatic neuroendocrine tumors: recent advances and future perspectives

INTRODUCTION

Well-differentiated pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of primary tumors of the endocrine pancreas. Dysregulation of chromatin remodeling, gene expression alteration, global DNA hypomethylation of non-coding regions, DNA hypermethylation and silencing of tumor suppressor gene promoters are frequent epigenetic changes in PanNETs. These changes exert a role in neoplastic transformation and progression. As epigenetic mechanisms, converse to genetic mutations, are potentially reversible, they are an interesting and promising therapeutic target for the treatment of PanNETs.

AREAS COVERED

We reviewed main epigenetic alterations associated with the development, biological and clinical features and progression of PanNETs, as well as emerging therapies targeting epigenetic changes, which may prove effective for the treatment of human PanNETs.

EXPERT OPINION

Constant advances in the PanNET medical approach, as reported in the clinical and therapeutic recommendations of ESMO, improved the overall survival of patients over the years. However, over 60% of the patients with metastatic disease still have poor prognosis. Epigenetic regulator drugs, currently approved to treat some human malignancies, that showed anti-tumoral activity also on PanNETs, in pre-clinical and clinical studies, could concur to ameliorate the prognosis and OS of advanced and metastatic PanNET, in combination with surgery and currently employed medical therapies.

Comparison of Design, Eligibility, and Outcomes of Neuroendocrine Neoplasm Trials Initiated From 2000 to 2009 vs 2010 to 2020

Importance

Neuroendocrine neoplasms (NENs) have historically been grouped homogenously in clinical trials, despite their heterogeneity. Given the adoption of a more advanced pathologic classification system and drug licensure of several targeted therapies over the last decade, information is needed on whether study characteristics of NEN studies have evolved.

Objective

To assess changes in study design, eligibility, accrual, sponsorship, and outcomes between phase II or III NEN clinical trials that began enrollment from 2000 to 2009 vs 2010 to 2020.

Design, Setting, and Participants

This quality improvement study used a systematic survey of completed studies published between January 1, 2000, and December 31, 2020. Therapeutic phase II and III NEN studies were identified through a database search of Medline (via PubMed), EMBASE (OvidSP), Cumulative Index of Nursing and Allied Health Literature (EBSCOhost), Web of Science (Clarivate), Cochrane Database of Systematic Reviews (Wiley), ClinicalTrials.gov (National Institutes of Health), EU Clinical Trials Register, and National Cancer Institute Clinical Trials. Data were analyzed between March and June 2021.

Main Outcomes and Measures

Study characteristic proportions between the 2 enrollment periods.

Results

Of 3243 identified studies, 119 studies met criteria for inclusion, of which 117 studies (54 studies that began enrollment between 2000-2009 and 63 studies that began enrollment between 2010-2020) included exact dates of enrollment and were compared. Studies that began enrollment after 2010, compared with studies that began enrollment from 2000 to 2009, were less likely to include all NENs (13 studies [21%] vs 34 studies [63%]; P < .001) and more likely to include select NENs (eg, gastrointestinal neuroendocrine tumors, 25 studies [40%] vs 11 studies [20%]; P = .02; pancreatic neuroendocrine tumors, 32 studies [51%] vs 16 studies [30%]; P = .02). Studies that began enrollment after 2010, compared with studies that began enrollment from 2000 to 2009, were more likely to specify tumor differentiation (59 studies [98%] vs 34 studies [63%]; P < .001) or Ki-67 index (23 studies [38%] vs 5 studies [9%]; P < .001) in inclusion criteria. Studies that began enrollment after 2010, compared with studies that began enrollment from 2000 to 2009, were more likely to use progression-free survival (22 studies [35%] vs 9 studies [18%]; P = .04) rather than objective response rate (19 studies [30%] vs 27 studies [53%]; P = .01) as a primary or coprimary end point.

Conclusions and Relevance

These findings suggest that NEN trials enrolling over the last decade were more focused on select tumor populations, compared with studies that began enrollment before 2010. Despite this shift, more than 20% of studies still included all NENs. Studying novel agents in specific disease populations may enhance drug development in the field.

90Y/177Lu-DOTATOC: From Preclinical Studies to Application in Humans

The PRRT (Peptide Receptor Radionuclide Therapy) is a promising modality treatment for patients with inoperable or metastatic neuroendocrine tumors (NETs). Progression-free survival (PFS) and overall survival (OS) of these patients are favorably comparable with standard therapies. The protagonist in this type of therapy is a somatostatin-modified peptide fragment ([Tyr3] octreotide), equipped with a specific chelating system (DOTA) capable of creating a stable bond with β-emitting radionuclides, such as yttrium-90 and lutetium-177. In this review, covering twenty five years of literature, we describe the characteristics and performances of the two most used therapeutic radiopharmaceuticals for the NETs radio-treatment: [90Y]Y-DOTATOC and [177Lu]Lu-DOTATOC taking this opportunity to retrace the most significant results that have determined their success, promoting them from preclinical studies to application in humans.

It's more than just cancer biology: Health disparities in patients with pancreatic neuroendocrine tumors

BACKGROUND AND OBJECTIVES

Pancreatic neuroendocrine tumors (PNETs) represent a rare form of pancreatic cancer. Racial/ethnic disparities have been documented in pancreatic ductal adenocarcinoma, but health disparities have not been well described in patients with PNETs.

METHODS

A retrospective review of patients with PNETs in the National Cancer Database was performed for 2004-2014. Approximately 16 605 patients with PNETs and available vital status were identified. Survival was compared by race/ethnicity and socioeconomic status using Kaplan-Meier methods and Cox regression.

RESULTS

There were no significant differences in survival between Non-Hispanic, White; Hispanic, White; or Non-Hispanic, Black patients on univariate analysis. Kaplan-Meier analysis showed that patients from communities with lower median household income and education level had worse survival (p < 0.001). Patients age less than 65 without insurance, similarly, had worse survival (p < 0.001). Multivariable modeling found no association between race/ethnicity and risk of mortality (p = 0.37). Lower median household income and lower education level were associated with increased mortality (p < 0.001).

CONCLUSIONS

Unlike most other malignancies, race/ethnicity is not associated with survival differences in patients with PNETs. Patients with lower socioeconomic status had worse survival. The presence of identifiable health disparities in patients with PNETs represents a target for intervention and opportunity to improve survival in patients with this malignancy.

The quality of clinical trials in neuroendocrine tumours; have we learnt from our mistakes? An evaluation of phase II and phase III clinical trials

The quality and reporting of neuroendocrine tumour (NET) clinical trials has previously been found to be heterogeneous impairing trial interpretability. We aimed to perform an updated review of the quality of phase II/III clinical trials in NET to assess if trial design and reporting have improved since 2011. We performed a PubMed search for phase II/III trials evaluating systemic anticancer therapies or liver-directed therapies published between 2011 and 2018. Data collected comprised administrative data, study population characteristics, endpoints, reporting and statistical design parameters, and results. Sixty studies were included (5218 patients): 50 phase II and 10 phase III trials. Study populations were heterogeneous: 52% of trials allowed tumours from various primary sites, 28% allowed both well- and poorly-differentiated tumour morphology or did not specify, and 57% did not report proliferative indices and/or tumour grade in ≥80% of the study population. Only 36% of trials mandated radiological disease progression on participant enrolment using a validated measure. Statistical design and primary endpoint were clearly defined in 67% and 88% of trials, respectively. Toxicity (88%), radiological response rate (85%) and progression-free survival/time to progression (82%) were well reported in a majority of trials, but health-related quality of life was included in the minority. Of the randomised trials (n = 11), study populations were more homogeneous and study design was more often clearly defined; however, only 45% mandated radiological progression at baseline as measured per Response Evaluation Criteria In Solid Tumours, and reporting of health-related quality of life (55%) remained suboptimal. The design and reporting of NET clinical trials, predominantly of single-arm phase II trials, remains suboptimal and has not considerably improved over time despite the growth in our knowledge of the biology and unique characteristics of NETs. Higher quality is seen in randomised trials, although certain design and reporting elements remain inadequate in some studies. We must prioritise the design and conduct of NET clinical trials to effectively inform future research and guide practice change.

Current status of medical treatment for gastroenteropancreatic neuroendocrine neoplasms and future perspectives

Neuroendocrine neoplasms (NENs) constitute a heterogeneous group of tumors. In this review, we summarize the results of various clinical trials that have been conducted to investigate the efficacy and safety of various therapeutic options for NENs. Based on the encouraging results obtained from these trials, various therapeutic options have been established for the treatment of NENs, including somatostatin analogs (SSAs), molecularly targeted drugs and cytotoxic agents. In addition, peptide receptor radionucleotide therapy has recently been evaluated for the treatment of various NENs. We also discuss the approach for selecting the appropriate drugs and sequence of treatment with the various drug classes, as recommended by different treatment guidelines. Finally, we discuss the scope for future research in this field, especially into the merits of combination therapy with molecularly targeted drugs plus SSAs, along with ongoing studies.

Antiproliferative Systemic Therapies for Metastatic Small Bowel Neuroendocrine Tumours

OPINION STATEMENT

Neuroendocrine neoplasms (NENs) are a heterogeneous group of malignancies with rising incidence and prevalence. Outcome and therapy of small bowel neuroendocrine tumours (SBNETs) is variable, depending on the grade, differentiation, tumour burden, as well as the site of the tumour origin. Because of this, multidisciplinary approach is essential. Large randomized clinical trials, with somatostatin analogues (PROMID, CLARINET) or with peptide receptor radionuclide therapy (PRRT) with 177-lutetium (NETTER-1 trial) as well as the mammalian target of rapamycin inhibitor (mTOR) everolimus (RADIANT trials), represent milestones for the medical management of unresectable grade 1 and 2 SBNETS over the last decade. Novel therapies, such as tyrosine kinase inhibitors (TKI), are on the cutting edge. However, multiple unsolved questions remain. This review provides a comprehensive review of the main systemic therapeutic options for advanced SBNETs and discusses the latest guideline recommendations for palliative treatment.

Lenvatinib in Patients With Advanced Grade 1/2 Pancreatic and Gastrointestinal Neuroendocrine Tumors: Results of the Phase II TALENT Trial (GETNE1509)

PURPOSE

Approved systemic therapies for advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have shown limited capacity to reduce tumor burden and no antitumor activity after progression to targeted agents (TAs). We investigated the efficacy and safety of lenvatinib in patients with previously treated advanced GEP-NETs.

PATIENTS AND METHODS

This was a multicenter, single-arm, open-label, phase II trial with two parallel cohorts (ClinicalTrials.gov identifier: NCT02678780) involving 21 institutions in 4 European countries. Eligible patients had histologically confirmed advanced grade 1-2 pancreatic (panNET) or GI (GI-NET) NETs with documented tumor progression after treatment with a TA (panNET) or somatostatin analogs (GI-NET). Patients were treated with lenvatinib 24 mg once daily until disease progression or treatment intolerance. The primary end point was overall response rate by central radiology review. Secondary end points included progression-free survival, overall survival, duration of response, and safety.

RESULTS

Between September 2015 and March 2017, a total of 111 patients were enrolled, with 55 (panNET) and 56 (GI-NET) patients in each cohort. The median follow-up was 23 months. The overall response rate was 29.9% (95% CI, 21.6 to 39.6): 44.2% (panNET) and 16.4% (GI-NET). The median (range) duration of response was 19.9 (8.4-30.8) and 33.9 (10.6-38.3) months in the panNET and GI-NET groups, respectively. The median progression-free survival was 15.7 months (95% CI, 14.1 to 19.5). The most common adverse events were fatigue, hypertension, and diarrhea; 93.7% of patients required dose reductions or interruptions.

CONCLUSION

We report the highest centrally confirmed response reported to date with a multikinase inhibitor in advanced GEP-NETs, with a particularly strong response in the panNET cohort. This study provides novel evidence for the efficacy of lenvatinib in patients with disease progression following treatment with other TAs, suggesting the potential value of lenvatinib in the treatment of advanced GEP-NETs.

Development of the Functional Assessment of Cancer Therapy-Carcinoid Syndrome Symptom Index

OBJECTIVE

To develop a symptom-focused index to evaluate representative symptoms, treatment side effects, and emotional and functional well-being of patients with carcinoid syndrome (CS).

METHODS

The development of the Functional Assessment of Cancer Therapy-Carcinoid Syndrome Symptom Index (FACT-CSI) followed US Food and Drug Administration guidelines for the development of patient-reported outcome (PRO) measures and involved the following: (a) literature review; (b) interviews with 14 CS patients; (c) interviews with 9 clinicians; and (d) instrument development involving input from a range of PRO measure development and CS experts. The resulting draft instrument underwent cognitive interviews with 7 CS patients.

RESULTS

Forty-six CS sources were reviewed. Analysis of patient interviews produced 23 patient-reported symptoms. The most frequently endorsed physical symptoms were flushing, diarrhea, abdominal pain, fatigue, and food sensitivity/triggers. Seven priority CS emotional and functional themes were also identified by patients. Expert interviews revealed 12 unique priority symptoms - the most common being diarrhea, flushing, wheezing, edema, abdominal pain/cramping, fatigue, and 8 emotional and functional concerns. Through an iterative process of team and clinical collaborator meetings, data review, item reduction and measure revision, 24 items were selected for the draft symptom index representing symptoms, emotional concerns, global assessment of treatment side effects, and functional well-being. Cognitive interview results demonstrated strong content validity, including positive endorsement of item clarity (>86% across items), symptom relevance (>70% for most items), and overall measure content (86%).

CONCLUSIONS

The FACT-CSI is a content-relevant, symptom-focused index reflecting the highest priority and clinically relevant symptoms and concerns of people with CS.

Treatment of ampullary neuroendocrine tumor by Capecitabine (Xeloda®) and Temozolomide (Temodal®)

Neuroendocrine tumors of the gastrointestinal tract and pancreas include a range of rare and diverse neoplasms with unique tumor biology, natural history, and clinical management. Neuroendocrine tumors of the ampulla of Vater are extremely uncommon cancers that account for only about 0.3%-1% of all gastrointestinal neuroendocrine tumors. Approximately 139 cases have been reported to date. In this paper, we describe two patients with low to intermediate grades of ampullary neuroendocrine tumors that underwent multiple courses of chemotherapy with Capecitabine (Xeloda®) and Temozolomide (Temodal®). Our two patients had a dramatic response to this regimen. According to our study, it seems that ampullary neuroendocrine tumors have behavior like pancreatic neuroendocrine tumors which requires further studies in more patients.

Costs of treatment change following first-line somatostatin analog monotherapy among patients with neuroendocrine tumors

BACKGROUND

This study describes treatment characteristics and healthcare costs prior to and following treatment change from somatostatin analog (SSA) monotherapy among a privately-insured NET patient population in the US.

METHODS

Patients with newly diagnosed NET and treated with SSA monotherapy were retrospectively identified in IBM MarketScan claims between 1/1/2014 and 3/31/2019. NET treatment change was captured ≥30 days after the SSA start date (earliest new treatment = index date). Healthcare costs (reimbursed amount in 2019 dollars) were reported for 1, 3, and 6 months pre- and post-index intervals.

RESULTS

A total of 305 patients were identified (mean age: 58 years; female: 52%; metastatic disease: 49%). Most patients started on octreotide (81%) vs. lanreotide (19%). Common treatment changes included alternate SSA (38%), targeted therapy (30%), or chemotherapy (23%). Total costs increased on average by $13,272 between the month preceding and following treatment change (p < .001), with the highest increase among patients changing to targeted therapy ($19,677, p < .001) vs. an alternate SSA ($10,240, p < .001) or chemotherapy ($4,057, p = .155). The trajectory in mean cost difference using a 1, 3, and 6-month time period followed an increasing trend for patients who changed to targeted therapy (Δ$19,677, Δ$34,856, Δ$58,387) but was flat for patients who changed to the alternate SSA (Δ$10,240, Δ$10,026, Δ$11,727).

CONCLUSIONS

Higher total healthcare costs were observed following treatment change from first-line SSA. Switching to the alternate SSA was associated with a fixed, one-time cost; whereas, switching to targeted therapy was associated with both an initial switching cost and a persistent monthly increase.

Association between objective response rate and overall survival in metastatic neuroendocrine tumors treated with radioembolization: a systematic literature review and regression analysis

OBJECTIVES

Neuroendocrine tumors (NETs) are a heterogeneous group of cancers arising from neuroendocrine cells. The aim was to evaluate objective response rate (ORR) as a predictor of overall survival (OS) in patients with metastatic NETs (mNETs) treated with radioembolization (RE).

METHODS

Randomized controlled trials and observational studies of RE treatment of mNETs were identified by systematic literature review (SLR). Pooled ORR and OS estimates were calculated and a weighted generalized linear model (GLM) of ORR as a predictor of OS was derived, stratified by ORR assessment criteria and RE type (Yttrium-90 resin or glass microspheres).

RESULTS

The SLR identified 32 observational studies. Mean ORR was 41% (95% confidence interval 38-45%). The Yttrium-90 resin and glass microsphere GLMs accounted for 59% and 57% of OS deviance, respectively. ORR was a significant predictor of OS in the resin microspheres model (p < 0.001), but not the glass microspheres model (p = 0.11).

CONCLUSIONS

A weighted GLM showed a significant relationship between ORR and OS in patients with mNETs treated with Yttrium-90 resin microspheres. ORR could therefore potentially be an OS surrogate in future trials of Yttrium-90 resin microspheres. Further research is needed to confirm the relationship between ORR and OS and the difference between resin and glass microspheres.

Clinical and Translational Research Challenges in Neuroendocrine Tumours

Neuroendocrine tumours (NETs) represent a range of neoplasms that may arise from any (neuro)endocrine cell situated in any part of the human body. As any other rare diseases, NETs face several difficulties in relation to research. This review will describe some of the main challenges and proposed solutions faced by researchers with expertise in rare malignancies. Some of the most common challenges in clinical and translational research are enumerated in this review, covering aspects from clinical, translational and basic research. NETs being a heterogeneous group of diseases and a limited sample size of clinical and translational research projects are the main challenges. Challenges with NETs lay over the disparities between healthcare models to tackle rare diseases. NETs add an extra layer of complexity due to a numerous group of different entities. Prospective real-world data trials are an opportunity for rare cancers with the revolution of electronic health technologies. This review explores potential solutions to these challenges that could be useful not only to the NET community but also to other rare tumours researchers.

Long-term outcome of "Sandwich" chemo-PRRT: a novel treatment strategy for metastatic neuroendocrine tumors with both FDG- and SSTR-avid aggressive disease

OBJECTIVE

The primary aims of this study were to evaluate the long-term outcome of a "sandwich chemo-PRRT (SCPRRT)" regimen with regard to therapeutic response rate, progression-free survival (PFS), and overall survival (OS) rates in metastatic neuroendocrine tumors (NETs) with both somatostatin receptor (SSTR)- and fluorodeoxyglucose (FDG)-avid aggressive disease. Additionally, health-related quality of life (HRQoL) scales, clinical toxicity, and association of PFS and disease control rate (DCR) with various variables were also evaluated.

MATERIALS AND METHODS

A total of 38 patients of the aforementioned cohort, who received SCPRRT (at least 2 cycles of each PRRT and chemotherapy) at our institute between January 2012 and December 2018, were included and analyzed in this retrospective study. Between two cycles of ¹⁷⁷Lu-DOTATATE peptide receptor radionuclide therapy (PRRT), two cycles of oral capecitabine and temozolomide (CAPTEM) were sandwiched. Therapeutic responses following SCPRRT were assessed by using pre-defined criteria. PFS and OS after first SCPRRT were determined. Eastern Cooperative Oncology Group (ECOG) and Karnofsky score were used for evaluation of HRQoL before and after SCPPRT in all 38 patients. Any adverse events were graded according to the Common Terminology Criteria for Adverse Events version 5.0 (CTCAE v5.0) of the National Cancer Institute. Associations of PFS and DCR with various variables were evaluated.

RESULTS

Response (complete response and partial response) to SCPRRT was seen in 28 patients (73%), 15 patients (39%), and 16 patients (42%) on symptomatic, biochemical, and molecular imaging response evaluation criteria respectively. A total of 17 patients (45%) had anatomical imaging response with DCR of 84% based upon the RECIST 1.1 criteria. Pre-therapy mean ECOG and KPS was 2.0 and 68, which changed to 1.0 and 75 respectively following SCPRRT. Long-term follow-up data was available and ranged from 12 to 65 months after the first SCPRRT. Median PFS and OS were not reached at a median follow-up of 36 months. An estimated PFS rate of 72.5% and OS rate of 80.4% was found at 36 months. Longer PFS was dependent upon high SSTR uptake and number of CAPTEM cycle (≥ 7 cycles), absence of skeletal metastasis, and no previous external beam radiotherapy (EBRT) exposure with significant P value. Higher DCR was dependent upon absence of skeletal metastasis with significant P value. SCPRRT was tolerated well with none developing grade 4 hematotoxicity and nephrotoxicity of any grade. Anemia (grade 3), thrombocytopenia (grade 3), and leukopenia (grade 3) were noticed in 1 patient (2.5%), 2 patients (5%), and 1 patient (2.5%) respectively in this study.

CONCLUSION

Thus, favorable response rates with effective control of symptoms and longer PFS and OS without high-grade or life-threatening toxicities were important observations in the present study following SCPRRT in NET patients with aggressive, both FDG- and SSTR-avid, metastatic progressive disease. The study results indicate the potential role of "sandwich chemo-PRRT" in future therapeutic algorithms of aggressive, both SSTR- and FDG-positive subset of neuroendocrine tumors.

THE ROLE OF CONVENTIONAL ECHOENDOSCOPY (EUS) IN THERAPEUTIC DECISIONS IN PATIENTS WITH NEUROENDOCRINE GASTROINTESTINAL TUMORS

Background:

Gastrointestinal neuroendocrine tumors are rare, usually presented as subepithelial or polypoid tumors. Accurate diagnosis and indication of the type of resection are still challenging.

Aim:

To determine the effectiveness of echoendoscopy in determining the depth of the lesions (T) identified by endoscopy in order to evaluate surgical and/or endoscopic indication, and to evaluate the results of endoscopic removal in the medium term.

Methods:

Twenty-seven patients were included, all of whom underwent echoendoscopy for TN tumor staging and the evaluation of possible endoscopic resection. The parameters were: lesion size, origin layer, depth of involvement and identified perilesional adenopathies. The inclusion criteria for endoscopic resection were: 1) high surgical risk; 2) those with NET <2 cm; 3) absence of impairment of the muscle itself; and 4) absence of perilesional adenopathies in echoendoscopy and in others without distant metastases. Exclusion criteria were TNE> 2 cm; those with infiltration of the muscle itself; with perilesional adenopathies and distant metastases. The techniques used were: resection with polypectomy loop; mucosectomy with saline injection; and mucosectomy after ligation with an elastic band. The anatomopathological study of the specimens included evaluation of the margins and immunohistochemistry (chromogranin, synaptophysin and Ki 67) to characterize the tumor. Follow-up was done at 1, 6 and 12 months.

Results:

Resections with polypectomy loop were performed in 15 patients; mucosectomy in five; mucosectomy and ligation with elastic band in three and the remaining four were referred for surgery. The anatomopathological specimens and immunohistochemical analyzes showed positive chromogranin and synaptophysin, while Ki 67 was less than 5% among all cases. The medium-term follow-up revealed three recurrences. The average size of tumors in the stomach was 7.6 mm and in the duodenum 7.2 mm. Well-demarcated, hypoechoic, homogeneous lesions occurred in 75%; mucous layer in 80%; and the deep and submucosal mucosa in 70%.

Conclusions:

Echoendoscopy proved to be a good method for the study of subepithelial lesions, being able to identify the layer affected by the neoplasm, degree of invasion, echogenicity, heterogeneity, size of the lesion and perilesional lymph node involvement and better indicate the treatment option.

Liver-directed therapies for liver metastases from neuroendocrine neoplasms: Can laser ablation play any role?

Aggressive cytoreduction can prolong survival in patients with unresectable liver metastases (LM) from neuroendocrine neoplasms (NEN), and minimally invasive, liver-directed therapies are gaining increasing interest. Catheter-based treatments are used in disseminated disease, whereas ablation techniques are usually indicated when the number of LM is limited. Although radiofrequency ablation (RFA) is by far the most used ablative technique, the goal of this opinion review is to explore the potential role of laser ablation (LA) in the treatment of LM from NEN. LA uses thinner needles than RFA, and this is an advantage when the tumors are in at-risk locations. Moreover, the multi-fiber technique enables the use of one to four laser fibers at once, and each fiber provides an almost spherical thermal lesion of 12-15 mm in diameter. Such a characteristic enables to tailor the size of each thermal lesion to the size of each tumor, sparing the liver parenchyma more than any other liver-directed therapy, and allowing for repeated treatments with low risk of liver failure. A recent retrospective study reporting the largest series of LM treated with LA documents both safety and effectiveness of LA, that can play a useful role in the multimodality approach to LM from NEN.

Adjuvant therapy following resection of gastroenteropancreatic neuroendocrine tumors provides no recurrence or survival benefit

BACKGROUND AND OBJECTIVES

Lack of high-level evidence supporting adjuvant therapy for patients with resected gastroenteropancreatic neuroendocrine tumors (GEP NETs) warrants an evaluation of its non-standard of care use.

METHODS

Patients with primary GEP NETs who underwent curative-intent resection at eight institutions between 2000 and 2016 were identified; 91 patients received adjuvant therapy. Recurrence-free survival (RFS) and overall survival (OS) were compared between adjuvant cytotoxic chemotherapy and somatostatin analog cohorts.

RESULTS

In resected patients, 33 received cytotoxic chemotherapy, and 58 received somatostatin analogs. Five-year RFS/OS was 49% and 83%, respectively. Cytotoxic chemotherapy RFS/OS was 36% and 61%, respectively, lower than the no therapy cohort (P < .01). RFS with somatostatin analog therapy (compared to none) was lower (P < .01), as was OS (P = .01). On multivariable analysis, adjuvant cytotoxic therapy was negatively associated with RFS but not OS controlling for patient/tumor-specific characteristics (RFS P < .01).

CONCLUSIONS

Our data, reflecting the largest reported experience to date, demonstrate that adjuvant therapy for resected GEP NETs is negatively associated with RFS and confers no OS benefit. Selection bias enriching our treatment cohort for individuals with unmeasured high-risk characteristics likely explains some of these results; future studies should focus on patient subsets who may benefit from adjuvant therapy.

The clinical applications of a multigene liquid biopsy (NETest) in neuroendocrine tumors

PURPOSE

There are few effective biomarkers for neuroendocrine tumors. Precision oncology strategies have provided liquid biopsies for real-time and tailored decision-making. This has led to the development of the first neuroendocrine tumor liquid biopsy (the NETest). The NETest represents a transcriptomic signature of neuroendocrine tumor (NETs) that captures tumor biology and disease activity. The data have direct clinical application in terms of identifying residual disease, disease progress and the efficacy of treatment. In this overview we assess the available published information on the metrics and clinical efficacy of the NETest.

MATERIAL AND METHODS

Published data on the NETest have been collated and analyzed to understand the clinical application of this multianalyte biomarker in NETs.

RESULTS

NETest assay has been validated as a standardized and reproducible clinical laboratory measurement. It is not affected by demographic characteristics, or acid suppressive medication. Clinical utility of the NETest has been documented in gastroenteropancreatic, bronchopulmonary NETs, in paragangliomas and pheochromocytomas. The test facilitates accurate diagnosis of a NET disease, and real-time monitoring of the disease status (stable/progressive disease). It predicts aggressive tumor behavior, identifies operative tumor resection, and efficacy of the medical treatment (e.g. somatostatin analogues), or peptide receptor radionuclide therapy (PRRT). NETest metrics and clinical applications out-perform standard biomarkers like chromogranin A.

CONCLUSIONS

The NETest exhibits clinically competent metrics as an effective biomarker for neuroendocrine tumors. Measurement of NET transcripts in blood is a significant advance in neuroendocrine tumor management and demonstrates that blood provides a viable source to identify and monitor tumor status.

Three-dimensional Monte Carlo-based voxel-wise tumor dosimetry in patients with neuroendocrine tumors who underwent 177Lu-DOTATOC therapy

Background

Patients with advanced neuroendocrine tumors (NETs) of the midgut are suitable candidates for ¹⁷⁷Lu-DOTATOC therapy. Integrated SPECT/CT systems have the potential to help improve the accuracy of patient-specific tumor dosimetry. Dose estimations to target organs are generally performed using the Medical Internal Radiation Dose scheme. We present a novel Monte Carlo-based voxel-wise dosimetry approach to determine organ- and tumor-specific total tumor doses (TTD).

Methods

A cohort of 14 patients with histologically confirmed metastasized NETs of the midgut (11 men, 3 women, 62.3 ± 11.0 years of age) underwent a total of 39 cycles of ¹⁷⁷Lu-DOTATOC therapy (mean 2.8 cycles, SD ± 1 cycle). After the first cycle of therapy, regions of interest were defined manually on the SPECT/CT images for the kidneys, the spleen, and all 198 tracer-positive tumor lesions in the field of view. Four SPECT images, taken at 4 h, 24 h, 48 h and 72 h after injection of the radiopharmaceutical, were used to determine their effective half-lives in the structures of interest. The absorbed doses were calculated by a three-dimensional dosimetry method based on Monte Carlo simulations. TTD was calculated as the sum of all products of single tumor doses with single tumor volumes divided by the sum of all tumor volumes.

Results

The average dose values per cycle were 3.41 ± 1.28 Gy (1.91–6.22 Gy) for the kidneys, 4.40 ± 2.90 Gy (1.14–11.22 Gy) for the spleen, and 9.70 ± 8.96 Gy (1.47–39.49 Gy) for all ¹⁷⁷Lu-DOTATOC-positive tumor lesions. Low- and intermediate-grade tumors (G 1–2) absorbed a higher TTD compared to high-grade tumors (G 3) (signed-rank test, p =  < 0.05). The pre-therapeutic chromogranin A (CgA) value and the TTD correlated significantly (Pearson correlation:  = 0.67, p = 0.01). Higher TTD resulted in a significant decrease of CgA after therapy.

Conclusion

These results suggest that Monte Carlo-based voxel-wise dosimetry is a very promising tool for predicting the absorbed TTD based on histological and clinical parameters.

Everolimus after hepatic arterial embolisation therapy of metastases from gastrointestinal neuroendocrine tumours: The FFCD 1104-EVACEL-GTE phase II study

BACKGROUND

Hepatic arterial embolisation therapy (HAET) is a treatment of liver metastases of gastrointestinal neuroendocrine tumours (GI-NETs). HAET increases circulating vascular endothelial growth factor levels. Everolimus is a treatment in NETs that may have antiangiogenic activity.

METHODS

This phase II study was conducted in patients with predominant and progressive liver metastases from GI-NETs. Everolimus was initiated 7-30 days after HAET. The hypothesis was that everolimus after HAET would increase hepatic progression-free survival (hPFS) rate at 24 months from 35% to 50%.

RESULTS

Among the 74 patients included, 88% had small-bowel primary tumour, 43% had grade I and 57% grade II tumour, and 51% had extrahepatic metastases. Patients underwent one (n = 19), two (n = 54), or three (n = 1) HAET procedures. hPFS at 24 months was 33% (95% confidence interval [CI], 22.5-43.7); 40 (54%) patients had objective response. Median (95% CI) hPFS, PFS, and overall survival were 19 (14-23), 17 (13-22), and 51 (33-60) months. The most common grade III-IV toxicities (>5%) in patients receiving both HAET and everolimus (n = 67) were elevated liver enzymes (55%), fatigue (18%), diarrhoea (16%), anaemia (12%), hypertriglyceridaemia (7%) and mucositis (6%).

CONCLUSIONS

The primary end-point was not reached. This sequence allows high liver response with HAET, and everolimus controls the extrahepatic disease.

TRIAL REGISTRATION

NCT01678664 (clinicaltrials.gov).

Therapy of Patients with Neuroendocrine Neoplasia-Evidence-Based Approaches and New Horizons

Neuroendocrine tumors (NETs) show low but increasing incidence and originate in multiple organs, including the pancreas, midgut, caecum, rectum, appendix, colon, and lungs. Due to their stunning genetic, histological, and clinical variability, diagnosis and treatment of NETs are challenging. In addition, low incidence and high variability hamper the implementation of high evidence trials. Therefore, guidelines do not cover the complexity of NETs and, frequently, treatment decisions are taken by interdisciplinary tumor conferences at comprehensive cancer centers. Treatment aims are (i) control of tumor growth, (ii) symptom control, as well as (iii) the improvement of progression-free survival (PFS) and overall survival (OS). Here, we discuss high evidence trials facilitating the achievement of these treatment aims. The majority of the evidence exists for treatment with somatostatin analogue, everolimus, peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE, sunitinib, and telotristat. Among those, PRRT is the only treatment option that has the potential to control symptoms, stop tumor growth, and to improve PFS and OS. In contrast, only a low level of evidence exists for treatment with cytotoxic drugs such as streptozotocin and doxorubicine. Finally, we discuss novel treatment options by a combination of cytotoxic drugs, 177Lu-DOTATATE, and tyrosine kinase inhibitors to be tested in randomized prospective trials in the future. In addition, the application of innovative isotopes, such as 225Ac, for PRRT is discussed.

Systemic treatment for lung carcinoids: from bench to bedside

In the huge spectrum of lung neuroendocrine neoplasms, typical and atypical carcinoids should be considered as a separate biological entity from poorly differentiated forms, harboring peculiar molecular alterations. Despite their indolent behavior, lung carcinoids correlate with a worse survival. To date, only limited therapeutic options are available and novel drugs are strongly needed. In this work, we extensively reviewed scientific literature exploring available therapeutic options, new molecular targets and future perspectives in the management of well differentiated neoplasms of bronchopulmonary tree. Systemic therapy represents the main option in advanced and unresectable disease; accepted choices are somatostatin analogs, peptide receptor radionuclide therapy, everolimus and chemotherapy. To date, an univocal treatment strategy has not been identified yet, thus tailored therapeutic algorithms should consider treatment efficacy as well as safety profiles. Several molecular alterations found in carcinoid tumors might act as molecular targets leading to development of new therapeutic options. Further studies are necessary to identify new potential “druggable” molecular targets in the selected subset of low-grade lung carcinoids. Furthermore, evaluating the available therapies in more homogeneous population might improve their efficacy through a perfect tailoring of treatment options.

Genomic characterization of a well-differentiated grade 3 pancreatic neuroendocrine tumor

Pancreatic neuroendocrine neoplasms (PanNENs) represent a minority of pancreatic neoplasms that exhibit variability in prognosis. Ongoing mutational analyses of PanNENs have found recurrent abnormalities in chromatin remodeling genes (e.g., DAXX and ATRX), and mTOR pathway genes (e.g., TSC2, PTEN PIK3CA, and MEN1), some of which have relevance to patients with related familial syndromes. Most recently, grade 3 PanNENs have been divided into two groups based on differentiation, creating a new group of well-differentiated grade 3 neuroendocrine tumors (PanNETs) that have had a limited whole-genome level characterization to date. In a patient with a metastatic well-differentiated grade 3 PanNET, our study utilized whole-genome sequencing of liver metastases for the comparative analysis and detection of single-nucleotide variants, insertions and deletions, structural variants, and copy-number variants, with their biologic relevance confirmed by RNA sequencing. We found that this tumor most notably exhibited a TSC1-disrupting fusion, showed a novel CHD7–BEND2 fusion, and lacked any somatic variants in ATRX, DAXX, and MEN1.

Dehydrocostus lactone inhibits in vitro gastrinoma cancer cell growth through apoptosis induction, sub-G1 cell cycle arrest, DNA damage and loss of mitochondrial membrane potential

INTRODUCTION

The purpose of the present study was to evaluate the antiproliferative activity of dehydrocostus lactone against human BON-1 cancer cell lines and to explore the possible underlying mechanism.

MATERIAL AND METHODS

MTT cell viability assay was used to determine cytotoxic effects of dehydrocostus lactone in BON-1 cells. Fluorescence and transmission electron microscopic (TEM) techniques were used to study the effect of the compound on cellular morphology and apoptosis. Flow cytometry was used to assess the effect on cell cycle phase distribution. Effects of the drug on cell apoptosis and mitochondrial membrane potential were analyzed by flow cytometry using annexin v and rhodamine-123 as fluorescent probes.

RESULTS

The results of the present study indicated that dehydrocostus lactone significantly (p < 0.01) inhibited the growth of BON-1 cancer cells. These growth inhibitory effects of dehydrocostus lactone on BON-1 were found to be time and concentration-dependent. The IC50 of dehydrocostus lactone were found to be 71.9 μM and 52.3 μM at 24 and 48 h time intervals respectively. The growth inhibitory effects of dehydrocostus lactone were found to be due to loss of mitochondrial membrane potential, the induction of apoptosis and sub-G1 cell cycle arrest.

CONCLUSIONS

Dehydrocostus inhibits in vitro gastrinoma cancer cell growth and therefore may prove beneficial in the management of gastrinoma cancer.

Current concepts in the diagnosis and management of neuroendocrine neoplasms of unknown primary origin

Neuroendocrine neoplasms (NENs) of unknown primary origin (UPO-NENs) are advanced neoplasms constituting 11-22% of all NENs that by definition their primary tissue of origin has not been identified with standard diagnostic work-up. Delineating the primary site of origin of UPO-NENs has important implications for selecting the appropriate treatment and overall prognosis. The small bowel, followed by the lung and pancreas are the most prevalent primary sites of origin of UPO-NENs that are uncovered during an extensive and prolonged diagnostic work-up; however, a number of UPO-NENs may still remain occult even after prolonged follow-up. A number of diagnostic algorithms that incorporate histopathological, molecular, imaging (either morphological or functional imaging), and serum biomarkers can help to identify the primary tumor origin. It is expected that advances in these fields will help reduce significantly the number of UPO-NENs.

Predicting Survival of Small Intestine Neuroendocrine Tumors: Experience From a Major Referral Center

OBJECTIVE

Neuroendocrine tumors (NETs) comprise 41.8% of small intestine malignancies. The NET nomogram is a 15-item prognostic tool that includes relevant factors for guiding management decisions. This is the first external validation of this tool among American patients at a tertiary treatment center.

METHODS

Patients who underwent surgical intervention from 2005 to 2017 were screened by retrospective chart review. Nomogram scores were calculated following the methods outlined by Modlin et al (Neuroendocrinology. 2010;92:143-157). Validation assessed the association between nomogram scores and survival using Wilcoxon test and Cox regression.

RESULTS

Among the 121 patients selected, the NET nomogram significantly predicted survival as a continuous variable (P < 0.01) and when dichotomized using 83 points to distinguish low-risk versus high-risk groups (P < 0.01). However, the nomogram was not universally applicable as even at our specialty center, variables such as chromogranin A and urinary 5-hydroxyindoleacetic acid are not routinely collected, whereas others, like tumor grade, do not reflect the most recently updated classifications.

CONCLUSION

The NET nomogram accurately identified patients at low and high risk of death. However, revision to update prognosticators could improve its usefulness for predicting survival of small intestine NETs.

FGD4 (Frabin) Overexpression in Pancreatic Neuroendocrine Neoplasms

OBJECTIVE

The pathogenesis of pancreatic neuroendocrine tumors (PNETs) is still unclear. We propose Frabin as a new molecular alteration in PNETs. Frabin is a guanine nucleotide exchange factor playing a role in mediating actin cytoskeleton changes during cell migration, morphogenesis, polarization, and division.

METHODS

Patients with PNETs of different grades were assessed for Frabin expression using immunohistochemistry and tissue microarray. The tissue microarray included 12 grade 1 and 3 grade 2 PNETs and 14 grade 3 pancreatic neuroendocrine carcinomas (PECAs). Frabin immunostain was scored with Allred system. Statistical analysis used SAS and R software. Immunohistochemistry scores were correlated with tumor grade and stage. The Spearman correlation coefficient was calculated with P values.

RESULTS

Pancreatic neuroendocrine tumors were graded according to the World Health Organization 2017 guidelines. Frabin was expressed by 24 (82.7%) of the PNET/PECA studied. Only 5 (17.2%) of the 29 PNETs/PECA evaluated were Frabin negative. Frabin expression was cytoplasmic in all cases. We found a significant positive correlation (ρ = 0.47) between Frabin immunohistochemistry score and tumor grade (P = 0.01). No correlation was found between Frabin expression and tumor stage (P = 0.91).

CONCLUSIONS

We report Frabin overexpression as a novel molecular alteration occurring in PNETs/PECAs.