Epidemiology, Incidence, and Prevalence of Neuroendocrine Neoplasms: Are There Global Differences?

Surufatinib in advanced neuroendocrine tumours: Final overall survival from two randomised, double-blind, placebo-controlled phase 3 studies (SANET-ep and SANET-p)

BACKGROUND

SANET-ep (NCT02588170) and SANET-p (NCT02589821) demonstrated the efficacy and safety of surufatinib versus placebo in patients with advanced extra-pancreatic and pancreatic neuroendocrine tumours (NETs). Here, we present a pooled analysis of final overall survival (OS) from two randomised phase 3 studies.

METHODS

The SANET studies were randomised, placebo-controlled, double-blind, phase 3 studies in China, comparing the efficacy and safety of oral 300-mg surufatinib (n = 265) versus placebo (n = 133) in patients with unresectable/metastatic, well-differentiated NETs (grade 1/2). After progression of disease or study unblinding, patients receiving placebo crossed over/switched to open-label surufatinib. By pooling the data from the two studies, OS analysis was completed using Kaplan-Meier methodology and a Cox proportional hazards model in the intention-to-treat population. Exploratory analyses were performed using different models to correct the confounding effect introduced by crossover. Long-term safety was assessed.

RESULTS

At study termination, 69 % of the placebo group had crossed over/switched to surufatinib. Median OS was 50.1 versus 46.8 months for patients initially on surufatinib versus those initially on placebo (stratified hazard ratio [HR] 0.935, 95 % confidence interval [CI] 0.684-1.278; p = 0.6727). After correcting the confounding effect introduced by crossover/switching, the HR ranged from 0.558 to 0.825. Commonly (≥10 %) reported treatment-related adverse events (grade 3/4) included hypertension and proteinuria.

CONCLUSION

OS of patients initially on surufatinib was not significantly longer versus patients initially on placebo, likely due to the high amount of crossover from placebo to surufatinib. No new safety signals were observed.

CLINICAL TRIALS REGISTRATION

SANET-ep (NCT02588170) and SANET-p (NCT02589821).

Accuracy of 177Lu activity quantification using MCNP5-Modeled SPECT imaging

The present study was conducted to assess the accuracy of 177Lu quantification using Monte Carlo N-Particle Transport Code, Version 5 MCNP5. The developed code was verified against calibration factor (CF) measured experimentally. The CF for converting SPECT data into units of activity concentration was determined by modeling two phantom configurations: (1) a uniform 177Lu concentration of 5.3600 ± 0.0005 MBq/mL in 20 mL Petri dish, resulting in a CF1 of 12.5 ± 1.5 cps/MBq, and (2) a 65.4 mL radioactive sphere (5.0 cm diameter) within a non-radioactive background in a cylindrical Jaszczak phantom, yielding a CF2 of 16.0 ± 2.0 cps/MBq. The significant difference between CF1 and CF2 (21.26 %) highlights the impact of phantom size and geometry on the calibration process. The quantification error was evaluated using recovery coefficient (RC) of the spherical inserts in a NEMA phantom. The established CFs and RCs provide a reliable framework for accurate activity quantification in 177Lu SPECT imaging using the established MCNP5 code. Our findings suggest that MCNP5 simulations can effectively model the SPECT imaging process, accounting for factors such as photon attenuation and scatter, offering the potential for improved dosimetry calculations in radionuclide therapy.

Novel framework for response evaluation criteria in grade 1/2 neuroendocrine tumors (RECIN) following [177Lu]Lu-DOTATATE therapy: post-hoc analysis of the phase 2 LuCAP trial

PURPOSE

Treatment response assessment in grade 1/2 neuroendocrine tumors (NETs) has been a key challenge due to their indolent nature. Here, we propose the novel response evaluation criteria with [68Ga]Ga-somatostatin analogue (SSA)-PET/CT in grade 1/2 NETs (RECIN) following [177Lu]Lu-DOTATATE therapy and evaluate its survival impact vis-à-vis conventional radiographic response assessment.

METHODS

This was a post-hoc analysis of the phase 2 LuCAP trial, wherein somatostatin receptor-positive, advanced grade 1/2 gastroenteropancreatic NET patients were treated with [177Lu]Lu-DOTATATE ± capecitabine. Tumor response assessment was done with serial [68Ga]Ga-DOTANOC-PET/CECT. Up to five target lesions were evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST 1.1) for radiographic response. Summed SULpeak of maximum five hottest lesions were evaluated for molecular response. Associations with progression-free survival (PFS) were evaluated using hazard ratios (HRs) and their 95% confidence intervals (95%CIs) along with Harrell's C-index.

RESULTS

Seventy-two patients were included with 23/72 (32%) patients achieving RECIST-partial response (PR). The novel RECIN-PR was defined as ≥ 25% decrease in summed SULpeak or conventional RECIST-PR with no signs of radiographic progression. Based on this, 40/72 (56%) patients achieved RECIN-PR. In particular, of the 42 patients with RECIST-stable disease, 17 (40%) had RECIN-PR. RECIN-PR was associated with significantly better PFS (HR: 0.33, 95%CI: 0.15-0.76; C-index: 0.67) and had better predictive ability compared to RECIST-PR (HR: 0.52, 95%CI: 0.21-1.29; C-index: 0.60).

CONCLUSION

In advanced grade 1/2 NETs treated with [177Lu]Lu-DOTATATE, [68Ga]Ga-SSA-PET/CT-based novel RECIN framework proved superior to conventional radiographic response assessment in terms of early response detection in indolent disease and better predictive ability.

CLINICAL TRIAL REGISTRATION

Clinical Trials Registry-India, CTRI/2020/01/022636.

The geographical distribution of neuroendocrine neoplasms in England (2012-2018)

Neuroendocrine Neoplasms (NEN) are increasing in incidence in England over the past two decades. Geographic and socio-economic disparities influence both incidence and survival rates. This study explores the relationship between environmental factors, access to specialised care in Centres of Excellence (CoE), and survival outcomes for NEN patients across England using Geographical Information Systems (GIS) to visualise disease distribution. Data on 19,958 NEN cases diagnosed between 2012 and 2018 were retrieved from the National Cancer Registry and Analysis Service (NCRAS) in England. GIS was used to analyse patient data, including spatial units, environmental factors, and travel times to CoE. Statistical analyses, including age-standardised rates, spatial autocorrelation, and survival analyses, were performed using QGIS, SPSS, R, and Stata software. Regional distribution showed the highest age-standardised rates (ASR) in the North-East, with lung NEN demonstrating significant spatial clustering. Environmental exposures, such as PM2.5 pollution, did not show a strong correlation with NEN distribution. Longer travel times to specialised centres were associated with worse overall survival, particularly in rural areas and among patients with higher socio-economic deprivation. Minor variations in survival rates were observed across different geographical regions when compared to London. This study highlights the uneven burden of disease across different regions in England. We have demonstrated variation in the country relating to anatomical sites and significant differences within rural or urban environments. Proximity to specialist centres was associated with better overall survival, highlighting the need for improved access to care.

Are epigenetic-targeting approaches ready for prime time in neuroendocrine neoplasms?

PURPOSE OF REVIEW

The purpose of this review is to evaluate the role of epigenetic-targeting approaches in the management of neuroendocrine neoplasms (NENs), particularly as a priming strategy for subsequent therapies. We explore the molecular basis of epigenetic modifications in NENs, and we review preclinical and clinical studies on DNA methyltransferase and histone deacetylase (HDAC) inhibitors.

RECENT FINDINGS

DNA methyltransferase and HDAC inhibitors can upregulate SSTR2 expression, thereby improving radioligand uptake and treatment response in NENs. The LANTana study investigates ASTX727 as a strategy to restore SSTR2 expression in metastatic NENs, allowing previously ineligible patients to receive PRRT. Preclinical studies demonstrate that combining epigenetic agents with radiotherapy, chemotherapy, or targeted inhibitors can enhance tumour sensitivity and overcome resistance.

SUMMARY

Epigenetic modifications play a crucial role in NENs, influencing tumour progression, therapy resistance, and SSTR2 expression. Epigenetic priming with DNA methyltransferase and HDAC inhibitors can enhance SSTR2 expression, improving the efficacy of PRRT in NENs. The LANTana study and other trials are investigating whether epigenetic-targeting approaches can be integrated into NEN treatment to optimize PRRT and overcome therapeutic limitations.

Survival Benefits of GLP-1 Receptor Agonists in Patients with Neuroendocrine Neoplasms: A Large-Scale Propensity-Matched Cohort Study

Background: Neuroendocrine neoplasms (NENs) represent a heterogeneous group of malignancies that consist of two major subtypes: neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs). Glucagon-like peptide-1 receptor agonists (GLP-1Ra) have demonstrated favorable results in preclinical studies, but their impact on NEN outcomes remains unexplored. Methods: Using the TriNetX US Research Network, we identified adult patients with NEN and either diabetes or obesity. After 1:1 propensity score matching based on demographics, comorbidities, procedures, and medication use, we compared survival outcomes between patients who received GLP-1Ra after NEN diagnosis and those who did not. Results: Among 32,464 eligible patients, 3139 received GLP-1Ra and 29,325 did not. After propensity matching, each cohort included 3043 patients with well-balanced baseline characteristics. During follow-up periods extending up to 15 years, all-cause mortality occurred in 356 (11.7%) GLP-1Ra users versus 753 (24.7%) non-users, representing a 13.0% absolute risk reduction (p < 0.001). GLP-1Ra use was associated with significantly improved survival (HR = 0.56, 95%CI = 0.49-0.63, p < 0.001). Both well-differentiated (HR = 0.52) and poorly differentiated tumors (HR = 0.56) showed significant improvement. Among primary sites, lung NENs demonstrated the most pronounced benefit (HR = 0.42). Tirzepatide showed the strongest association with reduced mortality (HR = 0.16), followed by semaglutide (HR = 0.27) and dulaglutide (HR = 0.52). Results: In this large propensity-matched study, GLP-1Ra use was associated with a 44.3% reduction in mortality risk among NEN patients with diabetes or obesity. The magnitude of the observed benefit suggests a potential role for GLP-1Ra as adjunctive therapy in this patient population. Prospective clinical trials are warranted to confirm these findings and explore underlying mechanisms.

Imaging of the Small Bowel Tumors

Small bowel tumors are rare gastrointestinal tumors. Neuroendocrine tumors are the most common and demonstrate unique subtypes depending on their location. Adenocarcinomas are most common in the duodenum demonstrating luminal narrowing and irregularity. Gastrointestinal stromal tumors are heterogeneously enhancing lesions with endophytic and/or exophytic growth patterns. Immunotherapy is a unique treatment of these tumors with tumoral response best assessed with both routine computed tomography (CT) and PET/CT. Primary small bowel lymphoma has many imaging patterns, most commonly being aneurysmal dilation and thickening of the small bowel. Metastases are common and may present as polypoid lesions, focal wall thickening, or serosal deposits.

Impact of multidisciplinary discussion on pancreatic neuroendocrine tumours, experience of a tertiary centre

BACKGROUND

Pancreatic neuroendocrine tumours (pNETs) are rapidly increasing. Their management implies considerable resources. Multidisciplinary discussion of tumours has become a cornerstone in clinical oncology but no studies demonstrate a clear clinical benefit. The aim of the present study is to evaluate whether the systematic discussion of patients with pNET in multidisciplinary meeting (MM) has changed their management.

METHODS

This retrospective single-centre study was held from 2004 to 2023. Since 2018 all patients were discussed in MM; thus, they were divided into two groups (board and no board) to evaluate clinical and surgical outcomes and whether multidisciplinary discussion improved adherence to guidelines.

RESULTS

A total of 128 patients were enrolled (55 board group and 73 no board). Groups were comparable for gender (36.4% female vs. 45.2%), mean age (60.3 vs. 61.7 years), mean American Society of Anesthesiologists score (2.66 vs. 2.71), Charlson Comorbidity Index (CCI) (CCI < 6, 80 vs. 79.45%), rate of functioning tumours (7.3 vs. 16.4%, P = 0.2), and pre/postoperative grading. Endoscopic ultrasound (EUS) was used more in board vs. no board (EUS: 90.9 vs. 71.2%, P = 0.005, EUS with fine-needle aspiration 89.1 vs. 65.8%, P = 0.002). More patients underwent surgery in no board (78.1 vs. 61.8%, P = 0.045). Postoperative complications were comparable as well as mortality (9.1 vs. 9.6%) and adherence to guidelines (board vs no board adherents: 90.3 vs. 87.6%, P = 0.9).

CONCLUSION

Systematic multidisciplinary discussion does not result in significant clinical impact in terms of surgical complications, recurrences, and reinterventions. A selective approach in multidisciplinary discussion would be worth considering.

Cancer Incidence and Mortality in Familial Adenomatous Polyposis Syndrome

BACKGROUND

Risk-reducing colectomy in familial adenomatous polyposis syndrome is the standard of care. This has increased the importance of surveillance for extracolonic malignancies in postcolectomy individuals.

OBJECTIVE

We sought to define the present-day incidence of all cancers and mortality in familial adenomatous polyposis.

DESIGN

Retrospective longitudinal cohort study.

SETTINGS

Two large academic hospitals.

PATIENTS

Eligible patients carried an APC pathogenic variant or met clinical criteria for familial adenomatous polyposis.

MAIN OUTCOME MEASURES

Cancer diagnosis, mortality, and associated risk factors.

RESULTS

A total of 358 patients were identified. The percentage who exhibited a classic familial adenomatous polyposis phenotype was 63.7%; 21.2% were de novo, and 82.7% had a colectomy. Colorectal cancer was the most common cancer (n = 59; 16.5%). Colorectal cancer diagnoses were associated with de novo familial adenomatous polyposis (OR 7.8 [95% CI, 3.51-17.35]; p < 0.001). Thyroid, duodenal/small bowel, gastric, and neuroendocrine tumors were reported in 7.5%, 3.1%, 2.8%, and 2.5% of patients, respectively. Rates of cancer were similar in classic and attenuated familial adenomatous polyposis. Thirty-nine patients (10.9%) died at a mean age of 49.6 ± 17.1 years. Twenty-six deaths were malignancy-related, and colorectal cancer was the leading cause (n = 10). All colorectal cancer-related deaths occurred in individuals with classic familial adenomatous polyposis, and 9 of 10 individuals were not previously diagnosed with the syndrome. Gastric and duodenal/small bowel cancers were the second leading causes (4 deaths each), and all occurred after colectomy. Fifty-nine percent of all deaths were attributable to a familial adenomatous polyposis-related malignancy or morbidity.

LIMITATIONS

Retrospective clinical data.

CONCLUSIONS

Colorectal cancer remains the most common malignancy and cause of death in familial adenomatous polyposis. However, nearly all colorectal cancer-related deaths occurred in individuals unaware of their familial adenomatous polyposis diagnosis, and none occurred in the attenuated syndrome. In patients who had a colectomy, gastric and duodenal/small bowel cancers are now the leading causes of death. See Video Abstract .

INCIDENCIA Y MORTALIDAD POR CNCER EN EL SNDROME DE POLIPOSIS ADENOMATOSA FAMILIAR

ANTECEDENTES:La colectomía para reducir el riesgo en el síndrome de poliposis adenomatosa familiar es el estándar de atención. Esto ha aumentado la importancia de la vigilancia de las neoplasias malignas extracolónicas en individuos post-colectomía.OBJETIVO:Buscamos definir la incidencia actual de todos los cánceres y la mortalidad en la poliposis adenomatosa familiar.DISEÑO:Estudio de cohorte longitudinal retrospectivo.ESCENARIO:Dos grandes hospitales académicos.PACIENTES:Los pacientes elegibles portaban una variante patogénica de APC o cumplían los criterios clínicos para la poliposis adenomatosa familiar.PRINCIPALES MEDIDAS DE RESULTADOS:Diagnóstico de cáncer, mortalidad,y factores de riesgo asociados.RESULTADOS:Se identificaron 358 pacientes. El 63,7% presentaban un fenotipo clásico de poliposis adenomatosa familiar, el 21,2% eran de novo y el 82,7% se había sometido a una colectomía. El cáncer colorrectal fue el cáncer más común (n = 59, 16,5%). Los diagnósticos de cáncer colorrectal se asociaron con poliposis adenomatosa familiar de novo (odds ratio 7,8 (IC del 95 % 3,51-17,35; p < 0,001)). Se informaron tumores de tiroides, duodenales/intestino delgado, gástricos y neuroendocrinos en el 7,5 %, 3,1 %, 2,8 % y 2,5 % de los pacientes, respectivamente. Las tasas de cáncer fueron similares en la poliposis adenomatosa familiar clásica y atenuada. 39 pacientes (10,9 %) murieron a una edad media de 49,6 ± 17,1 años. 26 muertes estuvieron relacionadas con neoplasias malignas y el cáncer colorrectal fue la causa principal (n = 10). Todas las muertes relacionadas con cáncer colorrectal ocurrieron en individuos con poliposis adenomatosa familiar clásica y 9/10 no habían sido diagnosticados previamente con el síndrome. El cáncer gástrico y de duodeno/intestino delgado fueron las segundas causas principales (4 muertes cada uno), y todas ocurrieron después de una colectomía. El 59% de todas las muertes fueron atribuibles a una neoplasia maligna o morbilidad relacionada con la poliposis adenomatosa familiar.LIMITACIONES:Datos clínicos retrospectivos.CONCLUSIONES:El cáncer colorrectal sigue siendo la neoplasia maligna y la causa de muerte más común en la poliposis adenomatosa familiar. Sin embargo, casi todas las muertes relacionadas con el cáncer colorrectal ocurrieron en personas que desconocían su diagnóstico de poliposis adenomatosa familiar, y ninguna ocurrió en el síndrome atenuado. En los pacientes que se sometieron a una colectomía, los cánceres gástrico y de duodeno/intestino delgado son ahora las principales causas de muerte. (Traducción-Dr Yolanda Colorado ).

A convolutional neural network-based system for identifying neuroendocrine neoplasms and multiple types of lesions in the pancreas using EUS (with videos)

BACKGROUND AND AIMS

EUS is sensitive in detecting pancreatic neuroendocrine neoplasm (pNEN). However, the endoscopic diagnosis of pNEN is operator-dependent and time-consuming because pNEN mimics normal pancreas and other pancreatic lesions. We intended to develop a convolutional neural network (CNN)-based system, named iEUS, for identifying pNEN and multiple types of pancreatic lesions using EUS.

METHODS

Retrospective data of 12,200 EUS images obtained from pNEN and non-pNEN pancreatic lesions, including pancreatic ductal adenocarcinoma (PDAC), autoimmune pancreatitis (AIP), and pancreatic cystic neoplasm (PCN), were used to develop iEUS, which was composed of a 2-category (pNEN or non-pNEN pancreatic lesions) classification model (CNN1) and a 4-category (pNEN, PDAC, AIP, or PCN) classification model (CNN2). Videos from consecutive patients were prospectively collected for a human-iEUS contest to evaluate the performance of iEUS.

RESULTS

Five hundred seventy-three patients were enrolled in this study. In the human-iEUS contest containing 203 videos, CNN1 and CNN2 showed an accuracy of 84.2% and 88.2% for diagnosing pNEN, respectively, which were significantly higher than that of novices (75.4%) and comparable with intermediate endosonographers (85.5%) and experts (85.5%). In addition, CNN2 showed an accuracy of 86.2%, 97.0%, and 97.0% for diagnosing PDAC, AIP, and PCN, respectively. With the assistance of iEUS, the sensitivity of endosonographers at all 3 levels in diagnosing pNEN has significantly improved (64.6% vs 44.8%, 87.5% vs 71.9%, and 74.0% vs 57.6%, respectively).

CONCLUSIONS

The iEUS precisely diagnosed pNEN and other confusing pancreatic lesions and thus can assist endosonographers in achieving more accessible and accurate endoscopic diagnoses with EUS. (Clinical trial registration number: ChiCTR2100049697.).

The Role of AI in the Evaluation of Neuroendocrine Tumors: Current State of the Art

Advancements in Artificial Intelligence (AI) are driving a paradigm shift in the field of medical diagnostics, integrating new developments into various aspects of the clinical workflow. Neuroendocrine neoplasms are a diverse and heterogeneous group of tumors that pose significant diagnostic and management challenges due to their variable clinical presentations and biological behavior. Innovative approaches are essential to overcome these challenges and improve the current standard of care. AI-driven applications, particularly in imaging workflows, hold promise for enhancing tumor detection, classification, and grading by leveraging advanced radiomics and deep learning techniques. This article reviews the current and emerging applications of AI computer vision in the care of neuroendocrine neoplasms, focusing on its integration into imaging workflows, diagnostics, prognostic modeling, and therapeutic planning.

Incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs): An updated systematic review of population-based reports from 2010 to 2023

There is a general perception that the incidence of neuroendocrine neoplasms (NENs) has been increasing. Nevertheless, reports of actual population-based studies are scarce, and pertinent data from some geographical regions still need to be available. In this systematic literature review of population-based studies, we aimed to evaluate the available data to provide updated figures on the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Guided by the PRISMA 2020 statement reporting items for systematic reviews, this study conducted a systematic search using Ovid in the bibliographic databases Embase, Medline, and Web of Science Core Collection. Only incidence-reporting studies were included. In total, 847 articles were identified, and through a strict evaluation process using predefined inclusion and exclusion criteria, we found 19 papers that reported the general incidence of GEP-NENs from all sites. In addition, we considered another 15 papers that focused on the epidemiologic aspects of single-organ studies. While the incidence rates of GEP-NEN vary across similar countries, the general incidence of GEP-NEN has been increasing worldwide in recent decades. The incidence of GEP-NENs has increased worldwide over the last two decades, and reliable figures from new regions add to this pattern. Nevertheless, variations in the classification, grading, and reporting of GEP-NENs in various studies make direct comparisons difficult.

Renal mucinous cystadenoma in the context of lynch syndrome and colonic neuroendocrine neoplasm: a case report

Renal mucinous cystadenoma (RMC) is an exceptionally rare finding with a poorly understood pathogenesis. Links between RMC and other malignancies are not well described, nor are there known associations with familial cancer disorders. We present the first case of RMC associated with Lynch syndrome (LS) and neuroendocrine neoplasm. A 56-year-old woman presented with iron deficiency leading to a diagnosis of a colonic mixed neuroendocrine-non-neuroendocrine carcinoma. After initial surgery, she experienced local recurrences at 6 and 12 months, treated with resection and adjuvant chemotherapy. Tumours displayed deficient MMR proteins with BRAF positivity, and germline testing confirmed LS. Surveillance subsequently revealed a complex cyst arising from a horseshoe kidney, for which she underwent a partial nephrectomy. Histopathology confirmed this to be renal mucinous cystadenoma arising from the pelvicalyceal system. This case underscores the need for further investigation into RMC pathogenesis and its potential association with LS.

The radiologic spectrum of neuroendocrine tumors in emergent care

Neuroendocrine tumors (NETs) are a diverse group of neoplasms whose prevalence is increasing globally, primarily due to advancements in diagnostic techniques. NETs arise from cells of the diffuse endocrine system and can occur in various locations, with the gastrointestinal tract being the most common. Their diverse clinical presentations, which range from asymptomatic to severe hormone-induced syndromes, pose significant diagnostic challenges. In emergency care, prompt recognition and management of complications such as bowel obstruction, ischemic events, hormonal crises, and metastases are critical. This review discusses the radiologic spectrum of NETs in emergent care, emphasizing the role of imaging in timely diagnosis and intervention.

Functioning neuroendocrine tumors (NET): Minimum requirements for a NET specialist

INTRODUCTION AND AIMS

Functioning neuroendocrine tumors (f-NETs) represent a minority of all NETs, however their management is challenging due to the impact on patients' survival and quality of life. In addition to f-NETs, paraneoplastic syndromes (PNS) are due to substances that are not related to the primary anatomical site, they can develop in different phases of NETs evolution, and might complicate the patient's clinical course. Dedicated guidelines are still scanty. We aim to review available literature on f-NETs to propose a useful tool for clinicians in order to improve the diagnostic process and the management.

METHODS

Narrative review focused on f-NETs.

RESULTS

The most common f-NETs include insulinomas, gastrinomas and carcinoid syndrome (CS)- associated NETs. Symptoms related to hormone production may overlap with other common endocrine and gastrointestinal disorders, highlighting the pivotal role of multidisciplinary management. Somatostatin analogs (SSAs) represent the gold standard first-line treatment of most f-NETs, often followed by or combined with other treatments (surgery, liver-directed therapies, targeted therapies, peptide receptor radionuclide therapy). Paraneoplastic syndromes can develop in different phases of NET evolution and might complicate the patient's clinical course and response to therapy.

CONCLUSIONS

The management of hormonal syndromes is challenging and must be based on the multidisciplinary approach. Herein, we pointed out the minimal requirements for a NET specialist in the diagnosis and treatment of f-NETs. Efforts should be made to improve the awareness of functioning forms, to understand their pathogenesis and to improve their management.

Utility of the manual hematology cell counter for Ki-67 assessment in gastrointestinal and pancreatobiliary well-differentiated neuroendocrine tumors

In the World Health Organization (WHO) 5th edition, prognosis of gastrointestinal (GI) well-differentiated neuroendocrine tumors (WDNET) depends on proliferation rate, commonly assessed by ki-67 immunohistochemical stain. In daily practice, the gold standard for WHO grade assessment by ki-67 staining, printing a photo of a tumor hotspot, counting the number of ki-67-positive cells out of 500 tumor cells, and calculating a percentage, is time-consuming and many cases are eyeballed. This study investigates the utility of a common tool, the manual cell counter used in hematology smear cell counting, for GI WDNET ki-67 counting. Of 59 resections, the number of cases with a WHO grade difference between gold standard print-and-count and the original report, eyeballing, and hematology counter method, was 23 (39 %), 14 (24 %) and 7 (12 %) cases, respectively. Of 37 biopsies, the number of cases with a WHO grade difference between gold standard print-and-count and the original report, eyeballing, and hematology counter method, was 10 (27 %), 12 (32 %) and 7 (19 %) cases, respectively. For resections, Chi square analysis comparing hematology counter method versus original report, where many cases were likely eyeballed, showed statistically significantly less cases with differing WHO grades from gold standard print-and-count for hematology counter-assessed cases (P = 0.0007), and the same Chi square analysis was marginally not significant (P = 0.09) for hematology counter versus eyeballing. Times taken to perform hematology counter method were statistically significantly lower than times taken for print-and-count. This study suggests the hematology cell counter could strike a reasonable balance between time and accuracy for WDNET resections.

Evaluating the prognostic significance of the pre-treatment neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios in 177Lu-DOTATATE PRRT treated patients with advanced metastatic neuroendocrine tumors

PURPOSE

This study aimed to investigate the role of pre-treatment neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) in the prognosis assessment of 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy (PRRT) treated patients with advanced metastatic neuroendocrine tumors (NETs).

METHODS

Eligible PRRT-treated patients (n = 247, 2010-2019) were included. Pre-PRRT NLR and MLR were calculated from complete blood count data. Data on tumor characteristics, response to PRRT, progression-free survival (PFS), and overall survival (OS) were evaluated using COXPH analyses.

RESULTS

In NET patients, median values of NLR and MLR were 2.21 (IQR = 1.66-3.00) and 0.14 (IQR = 0.06-0.24), respectively. NLR showed significant positive association with G3 tumors (median = 3.64, IQR = 2.1-4.26, p = 0.022) and high 18F-FDG avidity (SUVmax>5) (median = 2.5, IQR = 1.82-3.56, p = 0.003). MLR was significantly associated with high disease burden (median = 0.18, IQR = 0.08-0.29, p = 0.0083). MLR distinguished between the PRRT non-responders with progressive disease and responders with complete/partial response (median 0.19 versus 0.12, p = 0.043) or responders with stable disease (median 0.19 versus 0.14, p = 0.045). The ratios independently correlated with disease progression and OS. Patients in NLRhigh (>3.5) group displayed significantly shorter median PFS and OS (48 and 58 months) compared to NLRlow (≤3.5) group (108 and 96 months) (p < 0.01). Patients in MLRhigh (>0.25) group displayed significantly shorter median PFS and OS (40 and 52 months) compared to MLRlow (≤0.25) group (108 and 102 months) (p < 0.01).

CONCLUSION

Pre-treatment NLR and MLR had an independent prognostic impact on disease progression and OS in PRRT-treated NET patients. This routine, inexpensive CBC-based test in the standard pre-PRRT workup demonstrates the prognostic value and may aid clinicians in the risk stratification of NET patients.

Diagnostic Performance of Combined Conventional CT Imaging Features and Radiomics Signature in Differentiating Grade 1 Tumors from Higher-Grade Pancreatic Neuroendocrine Neoplasms

BACKGROUND/OBJECTIVES

Accurate identification of grade 1 (G1) pancreatic neuroendocrine tumors (PanNETs) is crucial due to their rising incidence and emerging nonsurgical management strategies. This study evaluated whether combining conventional CT imaging features, CT radiomics features, and clinical data improves differentiation of G1 PanNETs from higher-grade tumors (G2/G3 PanNETs and pancreatic neuroendocrine carcinomas [PanNECs]) compared to using these features individually.

METHODS

A retrospective analysis included 133 patients with pathologically confirmed PanNETs or PanNECs (70 males, 63 females; mean age, 58.5 years) who underwent pancreas protocol CT. A total of 28 conventional imaging features, 4892 radiomics features, and clinical data (age, gender, and tumor location) were analyzed using a support vector machine (SVM) model. Data were divided into 70% training and 30% testing sets.

RESULTS

The SVM model using the top 10 conventional imaging features (e.g., suspicious lymph nodes and hypoattenuating tumors) achieved 75% sensitivity, 81% specificity, and 79% accuracy for identifying higher-grade tumors (G2/G3 PanNETs and PanNECs). The top 10 radiomics features yielded 94% sensitivity, 46% specificity, and 69% accuracy. Combining all features (imaging, radiomics, and clinical data) improved performance, with 94% sensitivity, 69% specificity, 79% accuracy, and an F1-score of 0.77. The radiomics score demonstrated an AUC of 0.85 in the training and 0.83 in the testing set.

CONCLUSIONS

Conventional imaging features provided higher specificity, while radiomics offered greater sensitivity for identifying higher-grade tumors. Integrating all three features improved diagnostic accuracy, highlighting their complementary roles. This combined model may serve as a valuable tool for distinguishing higher-grade tumors from G1 PanNETs and potentially guiding patient management.

Clinical characteristics and treatment patterns of patients with gastroenteropancreatic neuroendocrine neoplasia in Germany receiving peptide receptor radionuclide therapy: A real-world data registry-based study

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare malignancies deriving from the endocrine system in the gastrointestinal tract including the pancreas. Prognosis is greatly heterogenous due to its dependency on various factors, most importantly stage and differentiation. Several studies report an alarming rise in incidence in the past decade. Despite there being some therapeutical options, best therapy sequence still needs to be defined, particularly for unresectable and/or intermediate and high-grade NENs. Peptide receptor radionuclide therapy (PRRT) was approved in Europe and USA in 2017 and 2018, respectively. Studies with real-world systematic data on characteristics and treatment patterns of PRRT-receiving patients was non-existent at the time of this writing. In this retrospective study, we identified within the German NET-Registry 203 patients diagnosed with GEP-NEN having received PRRT from 1995 to 2023. We assessed general clinical patient characteristics, disease-specific characteristics, treatments and outcomes. To obtain a more up-to-date picture of treatment modalities and outcomes, a subgroup of the study population was allocated to the "therapy cohort," defined by patients with date of first diagnosis between 2010 and 2023 (open cohort). Mean age of the study population was 58 years (SD 12 years) with 51.7% being men. Most patients had a WHO performance score of 0 to 1 (41.4% and 50.5%, respectively). Most NEN cases were of small intestine/pancreatic origin (46.3% and 45.3%, respectively) and displayed well/moderate differentiation (55.3%). Ki-67 was generally within the 3% to 20% range (57.92%). Most patients presented with metastasis at diagnosis (73.9%). Somatostatin analogs (SSAs), chemotherapy and surgery were the most common non-PRRT therapy options (65.3%, 60.2%, and 50.0%, respectively). PRRT was most often applied as third- or second-line therapy (42.3% and 36.6%, respectively), usually after surgery and/or SSA treatment. As PRRT had been administered using different regimens, tumor response evaluation showed mixed responses. Given the low sample size and considerable amount of missing response data, no correlation analysis between PRRT sequencing and tumor response could be performed. Overall, the clinical characteristics and treatment patterns tend to follow trends observed in other studies or medical guidelines. Finally, this study presents real-world data that more accurately describes GEP-NEN disease in Germany and treatment modalities after PRRT's approval.

Real-World Study of Lanreotide Autogel in Routine Practice in Patients with Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs) in Hong Kong and Taiwan

INTRODUCTION

There is a lack of data on the efficacy, effectiveness, and safety of lanreotide autogel in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) of Chinese ethnicity. This noninterventional, retrospective study evaluated the effectiveness and safety of lanreotide autogel in patients of Chinese ethnicity with GEP-NETs in clinical practice.

METHODS

Patients' charts were abstracted from five hospitals in Hong Kong and Taiwan (July-September 2021), where lanreotide autogel is approved for treating GEP-NETs. Included patients were adults with unresectable, metastatic, or locally advanced GEP-NETs who received a first injection (index) of lanreotide autogel 120 mg between 01 January 2017 and 30 June 2020 (planned sample size: N = 30). Follow-up ran from index to a maximum of 48 (± 4) weeks or until disease progression, start of new antitumor treatment, or death. The primary endpoint was progression-free survival (PFS) rate at week 48 (±4), and secondary endpoints included PFS rate at week 24 (±4), estimated using Kaplan-Meier analyses. All analyses were descriptive.

RESULTS

Of 27 patients enrolled, 22 (81.5%) had 48 weeks of follow-up. Tumors of pancreatic origin were the most common (73.9%). PFS rate was 0.96 (95% confidence interval: 0.72 - 0.99) at 24 weeks and 0.82 (0.53-0.94) at 48 weeks. Overall, 74.1% patients experienced ≥ 1 treatment-emergent adverse event; none were serious. No deaths were reported.

CONCLUSIONS

Lanreotide autogel was well tolerated and showed good tumor control rate in a real-world setting. These findings align with results from previous studies in Caucasian, Japanese, and Korean patients, thus supporting lanreotide autogel for treating patients with GEP-NETs of Chinese ethnicity.

Developing a peripheral blood RNA-seq based NETseq ensemble classifier: A potential novel tool for non-invasive detection and treatment response assessment in neuroendocrine tumor patients receiving 177Lu-DOTATATE PRRT

Neuroendocrine tumors (NETs) are presented with metastases due to delayed diagnosis. We aimed to identify NET-related biomarkers from peripheral blood. The development and validation of a multi-gene NETseq ensemble classifier using peripheral blood RNA-Seq is reported. RNA-Seq was performed on peripheral blood samples from 178 NET patients and 73 healthy donors. Distinguishing gene features were identified from a learning cohort (59 PRRT-naïve GEP-NET patients and 38 healthy donors). Ensemble classifier combining the output of five machine learning algorithms viz. Random Forest (RF), Extreme Gradient Boosting (XGBOOST), Gradient Boosting Machine (GBM), Support Vector Machine (SVM), and Logistic Regression (LR) were trained and independently validated in the evaluation cohort (n = 106). The response to PRRT was evaluated in the PRRT cohort (n = 46) and the PRRT response monitoring cohort (n = 16). The response to 177Lu-DOTATATE PRRT was assessed using RECIST 1.1 criteria. The Ensemble classifier trained on 61 gene features, distinguished NET from healthy samples with 100% accuracy in the learning cohort. In an evaluation cohort, the classifier achieved 93% sensitivity (95% CI: 87.8%-98.03%) and 91.4% specificity (95% CI: 82.1%-100%) for PRRT-naïve GEP-NETs (AUROC = 95.4%). The classifier returned >87.5% sensitivity across different tumor characteristics and outperformed serum Chromogranin A sensitivity (χ2 = 21.89, p = 4.161e-6). In the PRRT cohort, RECIST 1.1 responders showed significantly lower NETseq prediction scores after 177Lu-DOTATATE PRRT, in comparison to the non-responders. In an independent response monitoring cohort, paired samples (before PRRT and after 2nd or 3rd cycle of PRRT) were analyzed. The NETseq prediction score significantly decreased in partial responders (p = .002) and marginally reduced in stable disease (p = .068). The NETseq ensemble classifier identified PRRT-naïve GEP-NETs with high accuracy (≥92%) and demonstrated a potential role in early treatment response monitoring in the PRRT setting. This blood-based, non-invasive, multi-analyte molecular method could be developed as a valuable adjunct to conventional methods in the detection and treatment response assessment in NET patients.

Immunohistochemical expression of ephrin receptors in neuroendocrine neoplasms: a case-series of gastroenteropancreatic neuroendocrine neoplasms and a systematic review of the literature

PURPOSE

Erythropoietin-producing hepatocellular (EPH) receptors are the largest known family of tyrosine kinases receptors (TKR) in humans, implicated in cell proliferation, adhesion, migration, tumor angiogenesis, invasion and metastasis. The aim of the present study is to assess the expression of EPHs in neuroendocrine neoplasms (NENs).

METHODS

Immunohistochemical staining of specimens of 30 patients with gastroenteropancreatic and lung NENs was performed for EPH-A1, EPH-A2, EPH-A4, EPH-A5 protein expression, in addition to ki-67 multiplication index and programmed death-ligand 1. Additionally, we performed a systematic review of the available literature in three different databases reporting on the expression of EPH in all neuroendocrine neoplasms.

RESULTS

Positive expression was seen in 16/19 (84%) specimens for EPH-A1, 15/23 (65%) for EPH-A2, 21/24 (88%) for EPH-A4, 24/26 (92%) for EPH-A5. EPH-A1 was expressed in 9/9 pancreatic, 3/4 small intestine, but not in one lung NEN, EPH-A2 in 5/10 pancreatic, 3/4 small intestine and lung, and in one of each of gastric, appendix, colorectal, and cervical NENs, respectively. EPH-A4 showed positive expression in 9/11 pancreatic, 4/4 small intestine, 3/3 lung specimens and EPH-A5 in 10/11, 4/4 and 4/4, respectively. Data retrieved from the systematic review of the literature in combination with the data from the present study are suggestive of a frequent EPH expression in pituitary, thyroid, lung and gastroenteropancreatic NENs, yet, with varying expressions of the single receptor subtypes.

CONCLUSION

EPHs may have a role in NEN tumorigenesis, prognosis as well as a role in the evolving molecular-targeted therapies.

Frontiers in radiopharmaceuticals for neuroendocrine tumors

Neuroendocrine tumors encompass a wide range of tumors which originate from neural crest cells. These tumors were thought to be rare tumors, however, with the advent of advanced diagnostic techniques along with better understanding of the clinical presentation and histology of these tumors, the incidence of these tumors is exponentially rising. As the incidence and detection rate of NENs increased, the concept of 'heterogeneity' came into picture, which in turn led to dual-tracer imaging with addition of FDG PET/CT. Despite an imaging-based decision-making approach for NENs, there is still a significant subset of patients where the imaging-based biomarkers fall short in disease assessment, prognostication and improving outcomes. Alternate pathways as well as better peptide vectors for targeting the somatostatin receptor need to be studied. In this article, we address the existing as well as emerging trends in radiopharmaceuticals used for NENs, which are likely to impact not just the diagnostic algorithms in future, but also management strategies.

Research process of PET tracers for neuroendocrine tumors diagnosis

Neuroendocrine tumors (NETs) can affect several organ systems and present a variety of clinical symptoms, which are difficult to diagnose by conventional methods. Somatostatin receptor (SSTR) is a group of specific receptors expressed on the well-differentiated NET cell membrane. [68Ga]-labeled somatostatin analogues (SSAs) PET/CT, endogenous ligands targeting SSTR, is widely used in currently clinical NETs diagnosis. The dual-tracer strategy ([68Ga]Ga-SSAs + [18F]FDG) allows for a more detailed evaluation of tumor metabolism and receptor expression. The NETPET score, integrating [68Ga]Ga-SSAs PET/CT and [18F]FDG PET/CT results, enhances the accuracy of predicting treatment response and prognosis. In addition, novel isotopes ([18F]/[64Cu]) labeled SSAs and SSTR antagonists outperformed [68Ga]-SSAs in lesion detection, tumor uptake, and tumor-to-background ratio. Due to undifferentiated or dedifferentiated NETs, SSTR may not be expressed. [68Ga]Ga-Pentixafor and [18F]-FDG PET/CT are applicable for SSTR-negative NET diagnosis. [18F]-MFBG and [18F]-DOPA have a higher sensitivity for identifying non-metastatic pheochromocytoma and paraganglioma (PPGL) than other radiotracers. This review addressed NET diagnosis with conventional imaging techniques, the clinical application of novel radiotracers, and the merits and limitations of the various radiotracers.

Treatments and Outcomes in Neuroendocrine Patients Treated with Long-Acting Somatostatin Analogues: An Italian Real-World Propensity Score-Matched Cohort Study

Objectives: The aim of this study was to investigate the treatment patterns and outcomes in two propensity score-matched cohorts of patients with neuroendocrine tumours (NETs) treated with first-line somatostatin analogue (SSA). Methods: Metastatic NET patients treated with first-line SSA (2009-2022) were retrospectively examined. First-line lanreotide vs. octreotide cohorts were matched 1:1 by propensity scores for demographics, tumour characteristics, and diagnosis year. Progression-free survival (PFS) and overall survival (OS) were analysed using Kaplan-Meier analysis and the Cox proportional hazards model. Results: Among 441 patients, 310 were matched (155 in both the octreotide and lanreotide groups). First-line SSA was monotherapy (63.5%) or combination with other medications (36.5%). A total of 77% of second-line patients (188/244) maintained their initial SSA medication in combination with other therapies. Radioligand therapy with lanreotide (N = 72; 29.5%) or octreotide (N = 70; 28.7%) was the most common second-line treatment. First-line lanreotide and octreotide cohorts had similar median PFS (15.5; 95% CI: 13.6-19.1 vs. 14.0; 95% CI: 12.0-15.8 months), despite octreotide having a 36% higher likelihood of moving to the second line than lanreotide (95% CI: 1.05-1.76, p = 0.018). Multiple metastases (HR = 1.45; p = 0.004, 95% CI: 1.13-1.87) and Ki-67 > 20% (HR = 2.34; p < 0.001, 95% CI: 1.43-3.83) were significantly associated with the worst PFS. First-line lanreotide patients had a median OS of 10.4 years (95% CI: 7.5-NA) and octreotide 9.2 years (95% CI: 7.3-NA) (p = 0.537). Bone metastases increased death risk by 91% (p = 0.014; 95% CI: 1.14-3.20). Conclusions: SSA monotherapy is the main first-line treatment and most subsequent treatments include SSA with additional medications. Cohorts had similar PFS/OS, but octreotide demonstrated a 36% significantly higher likelihood of moving to the second-line treatment.

Nutritional aspects in neuroendocrine neoplasms. bridging the gap between dietary interventions and cancer care strategies: a scoping review

PURPOSE

Neuroendocrine neoplasms (NENs) represent heterogeneous tumors arising from neuroendocrine cells in different organs. Despite growing interest in the nutritional aspects of NEN management, research in this area is limited. Aim of this review is to summarize the current state of knowledge, highlight research gaps, and underscore the significance of nutrition in the comprehensive care of NEN patients.

METHODS

We conducted an extensive bibliographic search focusing on studies (including retrospective and prospective studies, systematic reviews, case series, and guidelines) exploring the relationship between nutritional assessments, dietary interventions, micronutrient deficiencies, and their impact on NEN outcomes.

RESULTS

Significant gaps exist in current research, particularly in understanding the specific nutritional needs of NEN patients and how tailored nutritional interventions can improve clinical outcomes. Evidence suggests that a high-fat Western diet may promote the growth of NEN, while a Mediterranean diet may help lower insulin levels and strengthen the immune system, potentially preventing tumor development. The ketogenic diet and intermittent fasting may also have positive impacts. Addressing common micronutrient deficiencies, such as vitamin D and niacin, is crucial to mitigate disease progression. There's a crucial need for future studies to include a comprehensive nutritional assessment incorporating patient-reported outcomes, to fully capture the impact of nutritional strategies.

CONCLUSION

Nutritional management, an important but under-researched facet of NEN treatment, significantly improves patients' quality of life and survival. Integrating nutrition into personalized cancer care is essential, highlighting the role of nutritional strategies in optimizing patient outcomes.

PET/MRI: pictorial review of hepatobiliary and pancreatic applications

PET and MRI both play valuable roles in the management of hepatobiliary and pancreatic (HBP) malignancies. Simultaneous PET/MRI combines the excellent soft-tissue resolution and anatomic details from MRI with functional information from PET in a single comprehensive examination. MRI is the main imaging modality in evaluating HCC, playing important roles in screening, characterization, local extent, and evaluating tumor response, whereas 18F-fluorodeoxyglucose (FDG) PET can help evaluate for lymph node involvement and metastatic disease. In cholangiocarcinoma and pancreatic malignancies, both PET and MRI have excellent utility in initial staging as well as assessing treatment response. In all HBP malignancies, FDG-PET/MRI is a unique problem-solving tool in complex cases and diagnostic challenges, especially after locoregional therapy and when differentiating residual or recurrent viable disease from inflammatory and other benign processes. In this manuscript, we review the role of PET/MRI in the diagnosis, staging, assessing treatment response, and characterizing post-treatment processes. With the introduction of multiple new tracers, the value of PET/MRI has not yet been fully realized, and more studies are needed to demonstrate the utility and efficacy of PET/MRI in improving patient care in hepatobiliary and pancreatic oncology.

Surgical Management of Gastroenteropancreatic Neuroendocrine Tumors

BACKGROUND/OBJECTIVES

Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from enterochromaffin cells that can arise from the gastrointestinal (GI) tract and pancreas. Surgical management is the cornerstone of treatment, with the optimal approach tailored by tumor grade, size, location, and presence of metastasis. This review discusses the current strategies for the surgical management of NETs of the gastroenteropancreatic tract.

METHODS

A review of the available literature was conducted to evaluate surgical approaches to NETs. Consensus guidelines were incorporated to synthesize evidence-based recommendations.

RESULTS

For gastric NETs, surgical approach depends on Rindi Classification, WHO grade, and tumor size, with endoscopic approaches favored for smaller and low-grade lesions. Small bowel NETs can be multifocal and thus often require a surgical approach with careful evaluation of the entire intestine. Pancreatic NETs are categorized as functional or non-functional, with enucleation or formal resection strategies based on size, location, functional status, and risk of malignancy. Colorectal NETs are primarily treated with transanal localized or formal surgical resection, depending on lesion size and depth of invasion or presence of lymph node involvement. Appendiceal NETs are either treated with appendectomy or right hemicolectomy, depending on the size, location, and invasiveness of the lesions. For metastatic NETs, cytoreduction, liver transplantation, and targeted therapies offer symptom relief and possible survival benefits.

CONCLUSIONS

Surgical resection provides curative potential for localized NETs and symptom control in metastatic cases. Future research is essential to refine guidelines for intermediate-risk lesions and multifocal tumors, ensuring optimal outcomes for patients with gastroenteropancreatic NETs.

Phase II Study of Nanoliposomal Irinotecan (Nal-IRI) with 5-Fluorouracil and Leucovorin in Refractory Advanced High-Grade Neuroendocrine Cancer of Gastroenteropancreatic (GEP) or Unknown Origin

BACKGROUND

Neuroendocrine carcinomas (NECs) are treated with a frontline platinum-etoposide combination with no standard second-line therapies. We explored a novel combination of nanoliposomal irinotecan (Nal-IRI), 5-fluorouracil (5-FU), and leucovorin (LV) in advanced refractory NECs and investigated the impact of UGT1A1*28 polymorphism on treatment outcomes and toxicity.

METHODS

We conducted an open-label, single-arm, multi-center Phase 2 trial in advanced NEC patients of gastroenteropancreatic (GEP) or unknown origin with progression or intolerance to first-line therapy. Eligible patients received nal-IRI 70 mg/m2 and leucovorin 400 mg/m2, followed by 5-FU 2400 mg/m2 biweekly till disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. Next-generation sequencing (NGS) was performed on blood/tissue samples at baseline and during treatment.

RESULTS

Eleven patients were enrolled, with nine evaluable for the primary endpoint. Seven were male, the median age was 66.7 years, and the median Ki-67 was 90%. We observed partial response in one patient, stable disease in six patients, and progressive disease in two patients. The median OS was 9.4 months (95% CI 2.9-29.3), and the median PFS was 4.4 months (95% CI 1.7-6.7). The most common adverse events were diarrhea (45%), nausea (45%), vomiting (45%), and fatigue (45%). The most common genetic mutations on NGS were TP53 (88.9%), CHEK2 (88.9%), and APC (33.3%). Patients with CHEK2 and APC mutation had longer PFS (p = 0.005 and p = 0.013, respectively). UGT1A1*28 polymorphism was not associated with OS, PFS, or toxicity.

CONCLUSION

Nal-IRI with 5-FU/LV is a safe and effective treatment for refractory high-grade NECs of GEP or unknown origin. Future studies should explore novel combinations with Nal-IRI in high-grade NECs both in frontline and refractory settings.

Predictive and prognostic nomogram models for liver metastasis in colorectal neuroendocrine neoplasms: a large population study

Background

In recent years, the incidence of patients with colorectal neuroendocrine neoplasms (CRNENs) has been continuously increasing. When diagnosed, most patients have distant metastases. Liver metastasis (LM) is the most common type of distant metastasis, and the prognosis is poor once it occurs. However, there is still a lack of large studies on the risk and prognosis of LM in CRNENs. This study aims to identify factors related to LM and prognosis and to develop a predictive model accordingly.

Methods

In this study, the Surveillance, Epidemiology, and End Results (SEER) database was used to collect clinical data from patients with CRNENs. The logistic regression analyses were conducted to identify factors associated with LM in patients with CRNENs. The patients with LM formed the prognostic cohort, and Cox regression analyses were performed to evaluate prognostic factors in patients with liver metastasis of colorectal neuroendocrine neoplasms (LM-CRNENs). Predictive and prognostic nomogram models were constructed based on the multivariate logistic and Cox analysis results. Finally, the capabilities of the nomogram models were verified through model assessment metrics, including the receiver operating characteristic (ROC) curves, calibration curve, and decision curve analysis (DCA) curve.

Results

This study ultimately encompassed a total of 10,260 patients with CRNENs. Among these patients, 501 cases developed LM. The result of multivariate logistic regression analyses indicated that histologic type, tumor grade, T stage, N stage, lung metastasis, bone metastasis, and tumor size were independent predictive factors for LM in patients with CRNENs (p < 0.05). Multivariate Cox regression analyses indicated that age, primary tumor site, histologic type, tumor grade, N stage, tumor size, chemotherapy, and surgery were independent prognostic factors (p < 0.05) for patients with LM-CRNENs. The predictive and prognostic nomogram models were established based on the independent factors of logistic and Cox analyses. The nomogram models can provide higher accuracy and efficacy in predicting the probability of LM in patients with CRNENs and the prognosis of patients with LM.

Conclusion

The factors associated with the occurrence of LM in CRNENs were identified. On the other hand, the relevant prognostic factors for patients with LM-CRNENs were also demonstrated. The nomogram models, based on independent factors, demonstrate greater efficiency and accuracy, promising to provide clinical interventions and decision-making support for patients.

Gastroenteropancreatic Neuroendocrine Tumors: Does Tumor Location Affect Prognosis?

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare entities. Generally, they can be localized anywhere in the gastrointestinal or hepatobiliary tract. The purpose of our study is to evaluate the effect of tumor location on prognosis in patients with GEP-NET undergoing surgery. Our secondary objective is to examine other factors affecting the prognosis of patients with GEP-NET.

METHODS

We retrospectively analyzed data from 30 patients with GEP-NET who underwent surgery in the General Surgery Clinic between 2012 and 2022. The gNET group (n=18) included tumors located in the gastrointestinal tract, while the pNET group (n=12) included tumors located in the hepatopancreatobiliary system. Surgical, laboratory, radiological, and pathological findings of the patients, as well as follow-up outcomes were recorded and statistically analyzed.

RESULTS

In subgroup comparison, tumor size was found to be larger in the pNET group (P=0.002). The statistical analysis of recurrence (16.7% versus 33.3%) and mortality rates (16.7% versus 41.7%) between the subgroups (P=0.329 and P=0.210, respectively) did not reveal a significant difference. When all patients were evaluated, it was observed that advanced age, presence of carcinoma diagnosis, higher tumor grade, advanced TNM stage, larger tumor size, presence of lymphovascular or perineural invasion, elevated mitotic index, higher Ki-67 index, and having received adjuvant therapy increased the rates of recurrence and mortality.

CONCLUSION

There was no statistically significant difference in survival outcomes between the GEP-NET groups located in the gastrointestinal tract and the hepatopancreatobiliary system.

Improving neuroendocrine tumor treatments with mathematical modeling: lessons from other endocrine cancers

Neuroendocrine tumors (NETs) occur sporadically or as part of rare endocrine tumor syndromes (RETSs) such as multiple endocrine neoplasia 1 and von Hippel-Lindau syndromes. Due to their relative rarity and lack of model systems, NETs and RETSs are difficult to study, hindering advancements in therapeutic development. Causal or mechanistic mathematical modeling is widely deployed in disease areas such as breast and prostate cancers, aiding the understanding of observations and streamlining in vitro and in vivo modeling efforts. Mathematical modeling, while not yet widely utilized in NET research, offers an opportunity to accelerate NET research and therapy development. To illustrate this, we highlight examples of how mathematical modeling associated with more common endocrine cancers has been successfully used in the preclinical, translational and clinical settings. We also provide a scope of the limited work that has been done in NETs and map how these techniques can be utilized in NET research to address specific outstanding challenges in the field. Finally, we include practical details such as hardware and data requirements, present advantages and disadvantages of various mathematical modeling approaches and discuss challenges of using mathematical modeling. Through a cross-disciplinary approach, we believe that many currently difficult problems can be made more tractable by applying mathematical modeling and that the field of rare diseases in endocrine oncology is well poised to take advantage of these techniques.

Epidemiology and survival analysis according to the histologic subtype of pancreatic cancer: a population-based cohort study

Purpose

This study investigated epidemiologic features of patients with pancreatic cancer in Korea, according to the histologic subtypes.

Methods

The Korea Central Cancer Registry data on patients with pancreatic cancer from 1999 to 2019 were reviewed. The 101,446 patients with pancreatic cancer (C25 based on the International Classification of Diseases, 10th revision) were allocated according to the following morphological codes: A, endocrine; B, carcinoma excluding cystic and mucinous; C, cystic or mucinous; D, acinar cell; and E, sarcoma and soft tissue tumor.

Results

The distribution of each pancreatic cancer subtype group in Korea from 1999 to 2019 was as follows: A, n = 3,101 (3.1%); B, n = 95,051 (93.7%); C, n = 2,856 (2.8%); D, n = 299 (0.3%); and E, n = 139 (0.1%). In group B, 49.2% of patients were aged >70 years, and half of them did not receive treatment within 4 months of diagnosis. In addition, only 30.9% of the patients were in the localized and regional stage in which surgical treatment was possible. Pancreatic cancer occurred more frequently in females than in males only in group C. Between 1999 and 2019, the average annual percentage changes in the age-specific incidence rates were positive in groups A (13.9%, P < 0.001), B (1.0%, P < 0.001), and C (6.5%, P = 0.025). Significant improvements in 5-year survival rates over time were observed in subtypes A, B, and C.

Conclusion

The subgroups of pancreatic cancer show different epidemiologic features, including incidences, treatment rates, and prognoses.

Radioligand therapy in the therapeutic strategy for patients with gastro-entero-pancreatic neuroendocrine tumors: a consensus statement from the Italian Association for Neuroendocrine Tumors (Itanet), Italian Association of Nuclear Medicine (AIMN), Italian Society of Endocrinology (SIE), Italian Association of Medical Oncology (AIOM)

PURPOSE

This paper outlines the consensus of the Italian Association for Neuroendocrine Tumors(Itanet), the Italian Association of Nuclear Medicine (AIMN), the Italian Society of Endocrinology (SIE), and the Italian Association of Medical Oncology (AIOM) on treating neuroendocrine neoplasms (NENs)with radioligand therapy (RLT).

METHODS

A list of 10 questions regarding using RLT ingastroenteropancreatic neuroendocrine tumors (GEP-NETs) was addressed after a careful review of theavailable literature. compiling information from the MEDLINE database, augmented with expert opinionsand recommendations, aligns with the latest scientific research and the author's extensive knowledge.The recommendations are evaluated using the GRADE system, showcasing the level of evidence andthe strength of the recommendations.

RESULTS AND CONCLUSIONS

Specifically, this paper focuses on thesubcategories of well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs) thatexpress somatostatin receptors and are considered suitable for RLT, according to internationalguidelines.

Characteristics and function of the gut microbiota in patients with rectal neuroendocrine tumors

The gut microbiota plays a significant role in the initiation and progression of tumors, but its role in rectal neuroendocrine tumors (rNETs) remains unclear. Fecal samples were collected from 19 healthy individuals and 21 rNET patients,with the rNET cohort further divided into metastatic (rNETs-M) and non-metastatic (rNETs-nM) groups. Using metagenomic high-throughput sequencing, we analyzed the diversity, species composition, and functional characteristics of the gut microbiota. We applied a random forest model to identify potential microbial biomarkers for predicting rNET and specifically distinguishing rNETs-M cases. Alpha diversity analysis revealed that species diversity was lower in the rNETs group than in the control group. In contrast, the rNETs-M group exhibited higher species diversity than the rNETs-nM group. Beta diversity analysis demonstrated significant differences in community structure between the rNETs and control groups between the rNET-M and rNETs-nM groups. Notably, in the rNETs group, the abundance of potential pathogens such as Escherichia coli and Shigella was elevated.Furthermore, the rNETs-M group exhibited an increased abundance of potential pathogens such as Alistipes. KEGG enrichment analysis indicated that these distinct microbiota play a significant role in environmental information processing, genetic information processing, and metabolic pathways. Random forest analysis and ROC curve results identified Lachnospira pectinoschiza (AUC=0.885), Parasutterella muris (AUC=0.862), Sodaliphilus pleomorphus(AUC=0.956), Methylobacterium iners (AUC=0.971) as biomarkers with significant discriminatory value.

Circulating Chromogranin A as a Surveillance Biomarker in Patients with Carcinoids-The CASPAR Study

PURPOSE

Gastroenteropancreatic neuroendocrine tumors (GEP-NET) are relatively indolent but can be more aggressive. The current recommendations for using serum chromogranin A (CgA) for patients with GEP-NET are equivocal. This study was designed to validate an automated CgA immunofluorescence assay for monitoring disease progression in patients with GEP-NET.

PATIENTS AND METHODS

A prospective, multicenter, blinded observational study was designed to validate an automated CgA immunofluorescence assay for monitoring disease progression in patients with GEP-NET. Tumor progression was evaluated with RECIST 1.1 by CT/MRI. An increase ≥50% above the prior CgA concentration to a value >100 ng/mL in the following CgA concentration was considered positive.

RESULTS

A total of 153 patients with GEP-NET were enrolled. Using the prespecified cut-off of CgA change for tumor progression, specificity was 93.4% (95% confidence interval, 90.4%-95.5%; P < 0.001), sensitivity 34.4% (25.6%-44.3%), positive predictive value 57.9% (45.0-69.8), negative predictive value 84.3% (80.5-87.6), and AUC 0.73 (0.67-0.79).

CONCLUSIONS

Changes in serial measurements of serum CgA had a favorable specificity and negative predictive value, making this test a useful adjunct to routine radiographic monitoring.

Impact of sex differences on patients with neuroendocrine neoplasms during hospital admission

Background

Sex disparities are known modifiers of health and disease. In neuroendocrine neoplasms (NENs), sex-based differences have been observed in the epidemiology and treatment-related side effects.

Objectives

To examine sex differences in demographics, diagnoses present during hospital admission, comorbidities, and outcomes of hospital course among hospitalized patients with NENs.

Design

Retrospective analysis.

Methods

A descriptive analysis of sex differences was performed on patients with NENs discharged from U.S. community hospitals in 2019 from the National Inpatient Sample (NIS), Healthcare Cost and Utilization Project, and Agency for Healthcare Research and Quality.

Results

A total of 7334 patients with NENs were identified; 4284 patients had primary NENs, and 3050 patients had metastatic NENs. In total, 48.7% were males and 51.3% were females. Distributions of race and ethnicity, and payer types differed by sex (p < 0.001 and p = 0.027, respectively). For race and ethnicity, there were more females in White, Black, and Native American races, and Hispanic ethnicity. For payer types, female predominance was seen with Medicare, Medicaid, private insurance, and self-pay groups. Sex differences were seen in diagnosis made during hospital stay. In all NENs, oral (p = 0.036) and neurologic (p < 0.001) diagnoses were more common in females; ascites (p = 0.002), dysphagia (p = 0.002), biliary ductal obstruction (p = 0.014), and jaundice (p = 0.048) were more common in males. In primary NENs, ascites (p < 0.001) was male predominant. In metastatic NENs, dysphagia (p = 0.003) and jaundice (p = 0.034) were male predominant, whereas females had more headaches (p < 0.001). Nausea and vomiting were female predominant in all NENs (p < 0.001), primary (p = 0.044), and metastatic (p < 0.001) NENs. For comorbidities, arthropathies (p < 0.001), depression (p < 0.001), hypothyroidism (p < 0.001), other thyroid disorders (p < 0.001), chronic pulmonary disease (p = 0.002), and obesity (p < 0.001) were female predominant.

Conclusion

There were sex differences in the race and ethnicity, payer types, diagnoses present during hospital admission, and comorbidities among the 2019 NIS hospital discharge sample of patients with NENs.

eSOMA-DM1, a Maytansinoid-Based Theranostic Small-Molecule Drug Conjugate for Neuroendocrine Tumors

Background: The main challenges of conventional chemotherapy lie in its lack of selectivity and specificity, leading to significant side effects. Using a small-molecule drug conjugate (SMDC) ensures specific delivery of a cytotoxic drug to the tumor site by coupling it to a targeting vector. This promising strategy can be applied to neuroendocrine tumors (NETs) by choosing a targeting vector that binds specifically to somatostatin receptor subtype 2 (SSTR2). Additionally, incorporation of a bifunctional chelate into the molecule enables complexation of both diagnostic and therapeutic radionuclides. Thus, it facilitates monitoring of the distribution of the SMDC in the body and allows for the implementation of combination therapy. In our study, we designed eSOMA-DM1, a SMDC combining the SSTR2-targeted octreotate peptide and the cytotoxic agent DM1 via a chelate-bridged linker (N3-Py-DOTAGA). This approach warrants conjugation of the targeting vector and the drug at opposite sites to avoid undesired steric hindrance effects. Methods: Synthesis of the DM1 moiety (4) involved a three-step synthetic route, followed by the conjugation to the cyclic peptide, N3-Py-DOTAGA-d-Phe-cyclo[Cys-Tyr-d-Trp-Lys-Thr-Cys]-Thr-OH, through a copper-free click reaction, resulting in eSOMA-DM1. Subsequent labeling with [111In]InCl3 gave a high radiochemical yield and purity. In vitro assessments of eSOMA-DM1 binding, uptake, and internalization were conducted in SSTR2-transfected U2OS cells. Ex vivo biodistribution and fluorescence imaging were performed in H69-tumor bearing mice. Results: eSOMA-DM1 exhibited an IC50 value for SSTR2 similar to the gold standard DOTA-TATE. The uptake of [111In]In-eSOMA-DM1 in U2OS.SSTR2 cells was 1.2-fold lower than that of [111In]In-DOTA-TATE. Tumor uptake in H69-xenografted mice was higher for [111In]In-eSOMA-DM1 at all-time points compared to [111In]In-DOTA-TATE. Prolonged blood circulation led to increased accumulation of [111In]In-eSOMA-DM1 in highly vascularized tissues, such as the lungs, skin, and heart. Excretion through the kidneys, liver, and spleen was also observed. Conclusion: eSOMA-DM1 is a SMDC developed for NET showing promising characteristics in vitro. However, the in vivo results obtained with [111In]In-eSOMA-DM1 suggest the need for adjustments to optimize its distribution.

Small Insulinoma Followed-up as an Indolent Pancreatic Tumor

A woman in her 60s presented with a small pancreatic head tumor. Imaging studies revealed a 13-mm well-defined pancreatic head tumor. A neuroendocrine neoplasm was suspected, and the patient opted for observation at that time. After 8 months, the patient began experiencing sweating while fasting, and blood tests during regular follow-up visits showed hypoglycemia. Hypoglycemia was induced during fasting test. The tumor exhibited clear features of an insulinoma during follow-up observation. While small neuroendocrine neoplasms are often managed through observation, caution should be exercised regarding their transformation into functional neuroendocrine tumors.

Clinicopathological and epigenetic differences between primary neuroendocrine tumors and neuroendocrine metastases in the ovary

Currently, the available literature provides insufficient support to differentiate between primary ovarian neuroendocrine tumors (PON) and neuroendocrine ovarian metastases (NOM) in patients. For this reason, patients with a well-differentiated ovarian neuroendocrine tumor (NET) were identified through electronic patient records and a nationwide search between 1991 and 2023. Clinical characteristics were collected from electronic patient files. This resulted in the inclusion of 71 patients with NOM and 17 patients with PON. Histologic material was stained for Ki67, SSTR2a, CDX2, PAX8, TTF1, SATB2, ISLET1, OTP, PDX1, and ARX. DNA methylation analysis was performed on a subset of cases. All PON were unilateral and nine were found within a teratoma (PON-T+). A total of 78% of NOM were bilateral, and none were associated with a teratoma. PON without teratomous components (PON-T-) displayed a similar insular growth pattern and immunohistochemistry as NOM (p > 0.05). When compared with PON-T+, PON-T- more frequently displayed ISLET1 positivity and were larger, and patients were older at diagnosis (p < 0.05). Unsupervised analysis of DNA methylation profiles from tumors of ovarian (n = 16), pancreatic (n = 22), ileal (n = 10), and rectal (n = 7) origin revealed that four of five PON-T- clustered together with NOM and ileal NET, whereas four of five PON-T+ grouped with rectum NET. In conclusion, unilateral ovarian NET within a teratoma should be treated as a PON. Ovarian NET localizations without teratomous components have a molecular profile analogous to midgut NET metastases. For these patients, a thorough review of imaging should be performed to identify a possible undetected midgut NET and a corresponding follow-up strategy may be recommended.

An Update on the Management of Rectal Neuroendocrine Neoplasms

OPINION STATEMENT

Rectal neuroendocrine neoplasms (NENs) are increasing in incidence. Most lesions are low grade, well-differentiated neuroendocrine tumours with good long term outcomes. However there is metastatic potential and resection offers the only option for a cure and in most cases should be offered to reduce the risk of metastases. Careful staging of rectal NENs should be performed prior to consideration of resection in order to ensure the appropriate technique is chosen, and reduce the risk of incomplete resection. Resection can be endoscopic or surgical, and selecting the appropriate resection technique relies on tumour characteristics such as size, grade, invasion into the muscularis propria, presence of lymph node involvement or of distal metastases. Some patients may require systemic therapies which may involve somatostatin analogues (SSAs), everolimus, tyrosine kinase inhibitors (TKIs), chemotherapy or peptide receptor radionuclide therapy (PRRT). Due the rarity of these tumours, much of the evidence is based on retrospective reviews or smaller cohort studies. This article is an update of the current evidence available to guide management.

Small bowel neuroendocrine tumor presenting with chronic diarrhea and mesenteric ischemia: A case report

Key Clinical Message

The diagnosis of gastrointestinal neuroendocrine tumors is often challenging owing to the nonspecific presentation. This may lead to delayed diagnosis and serious, rare complications, such as acute mesenteric ischemia. This case highlights the importance of early recognition and the need for a multidisciplinary approach to managing such cases.

Abstract

Gastrointestinal (GI) neuroendocrine tumors (NETs) are rare neoplasms originating from neuroendocrine cells within the digestive tract. Despite their rarity, their incidence is increasing, necessitating a better understanding of their presentation and management. In the present report, we present a case of duodenal bulb NET that caused chronic diarrhea and unintentional weight loss for 2 years before manifesting as acute mesenteric ischemia. This case sheds light on the diagnostic challenges associated with GI NETs, particularly in cases with nonspecific symptoms. In addition, it underscores the importance of prompt recognition and management, as evidenced by the progression of the patient to acute mesenteric ischemia.

Efficacy and safety of surufatinib in the treatment of patients with neuroendocrine tumor: a real-world study in Chinese population

BACKGROUND

Neuroendocrine tumors (NETs) are rare neoplasms that originate from peptidergic neurons and neuroendocrine cells. Due to their increasing incidence, effective treatment strategies are required. Surufatinib, a novel small-molecule inhibitor with antiangiogenic and immunomodulatory effects, has shown promise in clinical trials for advanced NETs. However, the efficacy and safety of surufatinib are influenced by multiple factors, and there is currently a lack of sufficient real-world studies to explore these potential influencing factors.

METHODS

We conducted a retrospective study on 133 patients with NETs who were treated with surufatinib at Sun Yat-sen University Cancer Center. Patients were histologically confirmed to have primary NETs. Statistical analyses, including Cox regression models and Kaplan-Meier curves, were conducted to assess the impact of the primary tumor site on progression-free survival (PFS) and overall survival (OS).

RESULTS

Patients with gastroenteropancreatic NETs (GEP-NETs) exhibited significantly longer PFS and OS compared to extraGEP-NETs patients. Subgroup analyses also revealed variations in survival outcomes among patients with liver metastases depending on the primary tumor site. Adverse events (AEs), including proteinuria and increased bilirubin, were more common in GEP-NETs patients. These findings emphasize the importance of considering primary tumor site in treatment decisions for NETs.

CONCLUSIONS

Primary tumor site is a critical factor influencing the efficacy of surufatinib in NETs. Clinicians should consider this factor when determining treatment strategies.

Adverse Events of Radioligand Therapy in Patients with Progressive Neuroendocrine Neoplasms: The Biggest Eastern European Prospective Study

BACKGROUND

Neuroendocrine neoplasms (NENs) are neoplastic tumors developing in every part of the body, mainly in the gastrointestinal tract and pancreas. Their treatment involves the surgical removal of the tumor and its metastasis, long-acting somatostatin analogs, chemotherapy, targeted therapy, and radioligand therapy (RLT).

MATERIALS AND METHODS

A total of 127 patients with progressive neuroendocrine neoplasms underwent RLT-4 courses, administered every 10 weeks-with the use of 7.4 GBq [177Lu]Lu-DOTA-TATE or tandem therapy with 1.85 GBq [177Lu]Lu-DOTA-TATE and 1.85 GBq [90Y]Y-DOTA-TATE. Assessment of short- and long-term complications, as well as the calculation of progression-free survival (PFS) and overall survival (OS) were performed.

RESULTS

RLT caused a statistically but not clinically significant decrease in blood morphology parameters during both short- and long-term observations. Glomerular filtration rate (GFR) significantly decreased only in a long-term observation after RLT; however, it was clinically acceptable. Computed predictions of progression-free survival (PFS) and overall survival (OS) indicated that five years post-RLT, there is a 74% chance of patients surviving, with only a 58.5% likelihood of disease progression.

CONCLUSIONS

Computed predictions of PFS and OS confirmed treatment efficiency and good patient survival. RLT should be considered a safe and reliable line of treatment for patients with progressive NENs as it causes only a low number of low-grade adverse events.

Molecular Basis of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (NETs) are rare well-differentiated neoplasms with limited therapeutic options and unknown cells of origin. The current classification of pancreatic neuroendocrine tumors is based on proliferative grading, and guides therapeutic strategies, however, tumors within grades exhibit profound heterogeneity in clinical manifestation and outcome. Manifold studies have highlighted intra-patient differences in tumors at the genetic and transcriptomic levels. Molecular classification might become an alternative or complementary basis for treatment decisions and reflect tumor biology, actionable cellular processes. Here, we provide a comprehensive review of genomic, transcriptomic, proteomic and epigenomic studies of pancreatic NETs to elucidate patterns shared between proposed subtypes that could form a foundation for new classification. We denote four NET subtypes with distinct molecular features, which were consistently reproduced using various omics technologies.

Gastroenteropancreatic neuroendocrine neoplasms: epidemiology, genetics, and treatment

The incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) is increasing at a rapid pace and is becoming an increasingly important consideration in clinical care. Epidemiological data from multiple countries indicate that the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) exhibits regional, site-specific, and gender-based variations. While the genetics and pathogenesis of some GEP NEN, particularly pancreatic NENs, have been investigated, there are still many mechanisms that require further investigation. The management of GEP NEN is diverse, but surgery remains the primary option for most cases. Peptide receptor radionuclide therapy (PRRT) is an effective treatment, and several clinical trials are exploring the potential of immunotherapy and targeted therapy, as well as combination therapy.