Incidence and prevalence of neuroendocrine neoplasms in Norway 1993-2021

Incidence trends and relative survival of colorectal neuroendocrine neoplasms: A population-based study using German cancer registry data

Neuroendocrine neoplasms (NENs) of the colon and rectum are a heterogeneous group of epithelial neoplasms with neuroendocrine differentiation. They include well-differentiated neuroendocrine tumors (NETs), poorly differentiated neuroendocrine carcinomas (NECs) and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs). Our aim was to calculate incidence, incidence trends and relative survival for colonic and rectal NETs, NECs, and MiNENs. We analyzed data covering the entire German population recorded between 2009 and 2021, calculating age-standardized incidence rates, annual percent changes, and the relative 5-year survival probability for the calendar period 2017-2021. Our comprehensive analyses included 12,602 NEN cases, with 59% located in the rectum. NECs, MiNENs and tumors with colonic location showed higher stages. We observed an increase in the incidence of NETs, particularly in patients aged <55 years, and in the incidence of MiNENs, and a constant incidence of NECs. The relative five-year survival was high for rectal NETs (95.9%, 95%-CI 94.6; 97.1) and colonic NETs (81.4%, 95%-CI 78.3; 84.5) and low for colonic NECs (20.5%, 95%-CI 17.6; 23.4) and rectal NECs (19.2%, 95%-CI 15.7; 22.6). The increase in the incidence of NETs might be partly due to colorectal cancer screening, improved diagnostics, and changes in classification of NETs. We attribute the increase in incidence of MiNENs to the recent introduction of this morphological category. Higher stages at diagnosis, a higher proportion of NECs and higher median age at diagnosis may contribute to the less favorable survival probabilities associated with colonic as opposed to rectal location.

Appropriate use of tissue sampling and somatostatin receptor PET imaging in the diagnosis of pancreatic neuroendocrine tumors: results of an International Delphi Consensus

BACKGROUND

Current guidelines lack clarity regarding the appropriate use of preoperative ultrasound-guided (EUS) biopsy and receptor positron emission tomography (SSTR PET) imaging for pancreatic neuroendocrine tumors (PNETs). This study aims to reach expert consensus on the optimal sequencing of SSTR PET and EUS biopsy in the diagnostic workup and management of patients with suspected PNETs.

METHODS

A three-round modified Delphi process was used. A multidisciplinary panel of experts was recruited via snowball sampling. A set of 22 baseline statements pertaining to diagnostic workup, imaging, and biopsy was developed based on literature review and feedback obtained through a focus group. Survey rounds were conducted electronically and anonymously. A panel of international experts was asked to indicate whether they agreed, disagreed, or lacked the appropriate background to answer each statement. Of the 55 experts invited, 38 (69%) accepted to participate. Consensus was achieved with > 80% agreement.

RESULTS

Response rates were 97%, 100%, and 100% in rounds 1, 2, and 3, respectively. Following rounds 1 and 2, 29 final statements achieved consensus in the following three domains: diagnostic workup (15 statements), imaging (nine statements), and tissue sampling (five statements). Cronbach's alpha value, a measure of internal consistency, was 0.91 and 0.85 for rounds 1 and 2, respectively. The final set of statements achieved a 95% approval rate in round 3.

CONCLUSION

This international Delphi study provides expert consensus-based guidance on the appropriate use of EUS biopsy in the diagnostic workup of PNETs in the era of SSTR PET imaging.

Pancreatic Neuroendocrine Tumors-A Descriptive Study of the Presenting Features in a 20-Year Surgical Resection Cohort at a Tertiary Institution

OBJECTIVES

Pancreatic neuroendocrine tumors (pNETs) are uncommon, comprising 3%-7% of pancreatic tumors. With increasing incidence due to advanced imaging techniques, there is a need for detailed characterization of these tumors. This study aims to describe the clinical features, diagnostic evaluations, and pathology characteristics of pNETs in a large cohort from a single tertiary center, and to compare these findings with other larger cohort studies.

METHODS

We conducted a retrospective analysis of 866 patients with pNETs who underwent surgical resection at Mayo Clinic, Rochester, from March 2000 to December 2019. Data on demographics, clinical presentation, laboratory tests, imaging, and pathology were extracted and analyzed. Descriptive statistics were used to summarize the data.

RESULTS

The cohort had a median age of 57 years. Nonfunctional tumors were much more prevalent (77.5%), with functional tumors primarily being insulinomas (75.9%). Common presenting symptoms included gastrointestinal (45.3%) and nongastrointestinal symptoms (30.7%). Chromogranin A levels were elevated in 57.5% of patients. Imaging revealed enhancing lesions in most cases, with computed tomography scans performed in 90.9% of patients. Endoscopic ultrasound (EUS) identified tumors in 98.1% of cases, with EUS-FNA showing a sensitivity of 82%. Ki-67 index, used in 58.1% of cases, indicated grade 2 tumors as the most common (55.9%). Metastasis was observed in 39.4% of patients at the time of diagnosis, predominantly in the liver.

CONCLUSION

This study provides a comprehensive description of pNET characteristics in a large surgical cohort. Findings highlight the predominance of nonfunctional tumors and the importance of imaging and EUS in diagnosis. The data can aid in inter-institutional comparisons and enhance understanding of pNETs, contributing to improved patient management and future research.

Pancreatic neuroendocrine neoplasms coexisting with biliary intraductal papillary mucinous neoplasm: A case report and review of literature

BACKGROUND

Pancreatic neuroendocrine neoplasms (pNENs) are rare, heterogeneous tumors accounting for 1%-2% of pancreatic tumors, with significant malignant potential. Intraductal papillary mucinous neoplasm of the bile duct (IPMN-B) is a rare precancerous lesion in the bile duct system, with potential for malignancy. The combination of pNENs and IPMN-B is exceptionally rare and often leads to misdiagnosis. This study aims to report a rare case of pNENs combined with IPMN-B treated at Yanbian University Hospital to improve understanding and management of this unusual tumor combination.

CASE SUMMARY

We retrospectively analyzed a case from Yanbian University Hospital. We reviewed clinical records, imaging findings, endoscopic retrograde cholangiopancreatography, surgical exploration, and histopathological examination. The patient was diagnosed with pNENs and IPMN-B. Surgical treatment was performed, with follow-up showing effective management and no significant recurrence.

CONCLUSION

This case represents the first report of pNENs combined with IPMN-B. It highlights the need for thorough diagnostic evaluation to prevent misdiagnosis and improve treatment strategies.

Prognostic Features in Surgically Resected Well-Differentiated Pancreatic Neuroendocrine Tumors: An Analysis of 904 Patients with 7882 Person-Years of Follow-Up

Importance

The clinical behavior of well-differentiated pancreatic neuroendocrine tumors (PanNETs) is difficult to predict.

Objective

To define more accurately prognosticators for patients with a surgically resected PanNET.

Design

The pathology and Ki-67 immunolabeling index of PanNETs resected from 904 patients was correlated with patient outcome.

Setting

Academic tertiary care hospital.

Participants

Consecutive patients who had a PanNET resected between 1985 and 2025.

Results

The mean patient age at surgery was 56.6 years (SD 14.0), 477 were male (52.8%), and 7882 person-years of follow-up were obtained (mean 8.8 years, SD 6.5). The 10-year survival was 81% (95% CI: 77,86%) for patients with G1 PanNETs (Ki-67 <3%), 68% (95% CI: 61,76%) for patients with G2a PanNETs (Ki-67 3- <10%), 44% (95% CI: 29,66%) for patients with G2b PanNETs (Ki-67 of 10%- ≤20%), and 23% (95% CI: 8,61%) for patients with G3 PanNETs. Metastases (HR 4.7, p <0.0001), vascular invasion (HR 3.0, p <0.0001), tumor size ≥ 2 cm (HR 2.88, p <0.0001), perineural invasion (HR 2.42, p<0.0001), and positive margins (HR 2.18, p <0.0001) were associated with worse overall survival. Insulinoma (HR 0.34, p=3e-04), sclerosing variant (HR 0.47, p=0.05), and cystic variant (HR 0.61, p=0.05) were associated with improved overall survival. T stage and N stage were all statistically significant classifiers of overall survival. Similar associations were found with respect to disease relapse. There was a significant (P<0.001) increase in the proportion of patients diagnosed with stage I vs stage IV disease over time.

Conclusions and relevance

This study supports the classification of PanNETs into four grades (G1, G2a, G2b, and G3) based on Ki-67 labeling, which allows a more accurate prognostic assessments of patients.

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.

Towards a better registration of neuroendocrine neoplasms: The results of the Italian retrospective population-based study

BACKGROUND

The increasing incidence, rapidly evolving classification, rarity and heterogeneity of neuroendocrine neoplasms (NENs) pose challenges to NEN registration including difficulty in distinguishing neuroendocrine carcinoma (NEC) and neuroendocrine tumours (NETs). Thus, in Italy a higher NEC incidence was reported. Focusing on gastroenteropancreatic (GEP) NEN, we aimed to review GEP NEN, and in particular cases of neuroendocrine carcinoma, not otherwise specified (NOS) and estimate the incidence of NEN, NET and NEC of the GEP.MethodsWe launched a pilot study examining cases of neuroendocrine carcinomas NOS (ICD-O3 code 8246) of GEP incidents in the years 2012-2020. Cancer registries (CRs) reviewed information included in the pathology report regarding differentiation and tumour cells proliferation to decide whether to confirm the case as neuroendocrine carcinoma NOS or register it as NET or NEC. After the review, we estimated the GEP NEN, NET and NEC incidence.

RESULTS

Nine CRs contributed to the pilot study. After review, in all CRs, only 31% of GEP NOS neuroendocrine carcinomas were confirmed; 50% were recoded as NETs, and approximately 17% of cases were non-NENs. The IR of GEP NENs was 2.99/100,000, and the incidence of NETs was higher than that of NECs.

CONCLUSION

After the review, the incidence of GEP NEN, NET and NEC in the eight Italian CRs involved was comparable to that reported in other European countries.

IMPACT

Our results confirmed that heterogeneity of cancer registries in the registration of NEN requires collaborative work to define and promote a standard definition to be extended to all Italian registries.

Alternative lengthening of telomeres and Ki-67 proliferation index provide complementary information on recurrence risk after resection of pancreatic neuroendocrine tumors

Given the heterogeneous clinical behavior of pancreatic neuroendocrine tumors (pNETs), improved prognostic markers are needed to guide management and post-resection surveillance. Patients who underwent resection of large (≥3 cm) sporadic well-differentiated pNETs from 2000 to 2019 were identified. The Ki-67 proliferation index was determined using immunohistochemistry, and alternative lengthening of telomeres (ALT) status was assessed using fluorescence in situ hybridization. Recurrence-free and overall survival were estimated using Kaplan-Meier analysis. Multivariable Cox regression analysis evaluated factors associated with recurrence-free survival. A total of 106 patients were identified. ALT was positive in 57 (54%) and negative in 49 (46%). Ki-67 was ≥3% in 74 (70%) and <3% in 32 (30%). Tumors with Ki-67 ≥3% were more likely to be ALT positive (61% vs. 38%, p = .046). Stratifying by ALT status and Ki-67 proliferation index, median recurrence-free survival was 4.6 years for patients with ALT-positive/Ki-67 ≥3% tumors, 3.1 years for patients with ALT-positive/Ki-67 <3% tumors, 12.4 years for patients with ALT-negative/Ki-67 ≥3% tumors, and 20.2 years for patients with ALT-negative/Ki-67 <3% tumors (p < .001). Initial recurrence was distant in 82% and locoregional in 18%. Across all groups, overall survival was similar (p = .19). In multivariable analysis, advanced age, ALT positivity, perineural invasion, and lymph node metastases were associated with increased recurrence risk (all p < .05). ALT and Ki-67 provide complementary information on post-resection recurrence risk, which can guide subsequent surveillance and management strategies. These data support the incorporation of ALT testing into routine clinical practice.

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.

Childhood pancreatic neuroendocrine neoplasms: A national experience

Pancreatic neuroendocrine neoplasms (pNENs) diagnosed in childhood are very rare, with few data available. The aim was to describe the clinical presentation and behavior of children with pNENs at a national level.

METHODS

National multicenter retrospective study of all patients, aged from 0 to 17 years at diagnosis, treated from 2011 to 2020 for a pNEN and registered in the French National Registry of Childhood Cancers or FRACTURE database.

RESULTS

Fifteen patients, 13 well-differentiated pancreatic neuroendocrine tumors (pNETs) and two neuroendocrine carcinomas (pNECs), were selected. Median age at diagnosis was 14 years (range, 7-17). Eight patients, all with localized disease, had a cancer predisposition syndrome (CPS), including five cases diagnosed during systematic screening. Five (31%) had metastatic disease at diagnosis: three grade 2 pNETs and two pNECs. First line therapy included exclusive pancreatectomy (seven cases, all M0), active surveillance (three cases, all M0), medical therapies (somatostatin analogues, chemotherapy; four cases, all M1), and surgery with medical therapy (one M1 case). Three-year progression-free survival was 57% (confidence interval [CI] 95%: 27-78) and was significantly better for patients with low-grade well differentiated (73 vs. 0%; p < 10-4) and localized (76 vs. 20%; p = .02) tumors. The two patients with pNECs died. Three-year overall survival was 92% (CI95%: 59-99) and was significantly better in patients with low-grade tumor (100 vs. 50%; p = 10-4).

CONCLUSION

Childhood pNENs occur more frequently in adolescents with CPS. Localized low-grade pNETs in children have a very good prognosis, whereas the treatment of high-grade and metastatic pNETs/pNECs should be better defined.

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.

Neuroendocrine tumors in the stomach: An epidemiological analysis of Belgian Cancer Registry data 2010-2019

The prevalence of gastric NEN is estimated worldwide at 8.9% of all gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) and only 0.3%-1% of all gastric neoplasms, but is rising in the last decades. The aim of this project was to map the epidemiology of gastric neuroendocrine neoplasm (gNEN) in Belgium. This is a population-wide retrospective cohort study over 10 years (2010-2019), based on data from the Belgian Cancer Registry. A total of 641 patients were included; 605 patients with gNEN and 36 with MiNEN. The AAIR of gNEN was 0.67 per 100,000 person-years, increasing over the years and with a slight female predominance (55.4%). Neuroendocrine carcinoma (NEC) accounted for 15.7% (N = 95), with an AAIR of 0.11 per 100,000 person-years. The other 510 patients were diagnosed with gNET: G1 NET was most prevalent (54.3%) followed by G2 (32.5%) and G3 NET (3.5%). Concerning the clinical classification (type) of gNET, a diagnosis of type 1 tumors was presumed in 67.6%, type 3 tumors in 17.1% and type 2 tumors in 0.6% of patients. In only 3.8% of patients, the clinical classification was explicitly stated in the pathology report. Stage IV tumors were diagnosed in 13.4% (N = 81). A favorable evolution in pathology reporting is seen. Some variables-for example, clinical classification of gNET-were heavily underreported, stressing the importance of registries integrating clinical and pathological information.

Plasma Levels of Organic Acids Associated with the Gut Microbiome Display Significant Alterations in Neuroendocrine Tumor Patients

INTRODUCTION

The gut microbiome, allegedly involved in both healthy homeostasis and development of disease, is found to be associated with several types of cancer. Short-chain fatty acids (SCFAs), important metabolites derived from the gut microbiota, are described to carry both protective and promoting features in cancer development. Limited research exists on neuroendocrine tumors (NETs) and their association with microbiota-derived SCFAs. The aim of this study was to investigate possible alterations in plasma SCFAs/organic acids in NET patients compared to healthy controls.

METHODS

We quantified 11 organic acids, including SCFAs, in plasma from 109 NET patients (49 curatively operated patients and 60 patients with distant metastasis) as well as 20 healthy controls. Acids were quantified using liquid chromatography tandem mass spectrometry.

RESULTS

We found that levels of 3OH-propionic acid, 3OH-butyric acid, lactic acid, formic acid, acetic acid, glyoxylic acid, and glycolic acid were significantly altered in NET patients with metastatic disease, as well as curatively operated NET patients, compared to healthy controls (p < 0.05). In addition, a trend displaying increased acid level alterations from healthy controls in curatively operated patients with future recurrence, compared to patients with no documented recurrent disease, was detected.

CONCLUSION

Our results demonstrating significantly altered levels of multiple organic acids in NET patients represents a novel finding implicating further research on their role in NET pathophysiology.

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.

Incidence and survival of patients with malignant pancreatic neuroendocrine neoplasms in Germany, 2009-2021

BACKGROUND

Due to the rarity of pancreatic neuroendocrine neoplasms, only few population-representative studies on incidence and survival have been conducted. The aim was to provide up-to-date nationwide incidence and relative survival estimates of neuroendocrine (NE) neoplasms overall, NE tumors (NETs), NE carcinomas (NECs), and mixed NE neoplasms (MiNEN).

METHODS

We distinguished between pancreatic NETs (functioning versus non-functioning), NECs and mixed NE neoplasms and analyzed data from 2009 through 2021 from all German cancer registries covering a population of more than 80 million. We calculated crude and age-standardized incidence rates and 5-year relative survival estimates (RS).

RESULTS

Overall 6474, 4217, and 243 patients with pancreatic NETs, NECs, and mixed NE neoplasms, respectively were registered. While the age-standardized incidence of NETs has increased (+16.4 % per year, 95 %CI 12.2;20.7), the incidence of NEC has fallen (about -6.4 % per year, 95 %CI -8.0; -4.8). The crude RS was 77.7 % (standard error [SE] 0.9) for non-functioning NETs, 90.3 % for functioning NETs (SE 3.9), and 18.5 % (SE 3.9) for MiNEN. Large and small cell NECs had a low RS (9.1 % and 6.9 %, respectively). RS for G1 NETs was 88.2 %, while it was only 36.6 % for G3 NETs. Localized NETs had a RS of 92.8 %, while distant metastatic NETs had a RS of 45.0 %.

CONCLUSIONS

The incidence of pancreatic NETs has increased markedly in Germany in the period 2009-2021. Subgroups of NETs (G1 grading or localized stage) have an excellent prognosis. RS of MiNEN is more similar to NECs than NETs.

Diagnostic and prognostic biomarkers for pancreatic neuroendocrine neoplasms

This review examines the diagnostic and prognostic biomarkers for pancreatic neuroendocrine neoplasms (PanNENs), a heterogeneous group of tumors with expression of neuroendocrine markers. PanNENs include both well-differentiated pancreatic neuroendocrine tumors (PanNETs) and poorly differentiated pancreatic neuroendocrine carcinomas (PanNECs). The diagnosis is confirmed through markers such as chromogranin A, synaptophysin, and INSM1, which establish neuroendocrine differentiation. The World Health Organization classification categorizes PanNENs based on tumor differentiation and proliferative activity (Ki-67 and/or mitotic index) into well-differentiated PanNETs (grade 1 to grade 3) and poorly differentiated PanNECs. In most cases, the morphology and proliferation index are sufficient to distinguish PanNETs from PanNECs. However, distinguishing grade 3 PanNETs from PanNECs can be challenging on the basis of morphology and proliferative activity alone. Additional key diagnostic markers for distinguishing grade 3 PanNET from PanNEC include SSTR2A expression and molecular immunohistochemical markers such as p53, Rb1, menin, ATRX, and DAXX. PanNECs are by definition high-grade tumors with highly aggressive clinical behavior, while PanNETs have a variable prognosis that is difficult to predict using current biomarkers such as tumor grade and size. Several studies have shown that ATRX or DAXX loss is strongly associated with a higher risk of PanNET metastasis and recurrence. They are therefore key prognostic markers in PanNETs. In addition, chromosomal copy number variations can further help assess PanNET aggressiveness and prognosis. Molecular profiling is increasingly important for improving the diagnosis, treatment, and prognosis of PanNENs.

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.

Update in the management of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine neoplasms are a diverse group of neoplasms that can occur in various areas throughout the body. Well-differentiated neuroendocrine tumors (NETs) most often arise in the gastrointestinal tract, termed gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Although GEP-NETs are still uncommon, their incidence and prevalence have been steadily increasing over the past decades. The primary treatment for GEP-NETs is surgery, which offers the best chance for a cure. However, because GEP-NETs are often slow-growing and do not cause symptoms until they have spread widely, curative surgery is not always an option. Significant advances have been made in systemic and locoregional treatment options in recent years, including peptide-receptor radionuclide therapy with α and β emitters, somatostatin analogs, chemotherapy, and targeted molecular therapies.

Value of Surgical Cytoreduction in Patients with Small Intestinal Neuroendocrine Tumors Metastatic to the Liver and Peritoneum

BACKGROUND

Cytoreductive hepatectomy can improve survival and symptoms of hormonal excess in patients with small intestinal neuroendocrine tumor (siNET) liver metastases, but whether to proceed when peritoneal metastases are encountered at the time of planned cytoreductive hepatectomy is controversial.

METHODS

This was a retrospective review of patients who underwent surgical management of metastatic siNETs at Mayo Clinic between 2000 and 2020. Patients who underwent cytoreductive operation for isolated liver metastases or both liver and peritoneal metastases were compared.

RESULTS

Of 261 patients who underwent cytoreductive operation for siNETs, 211 had isolated liver metastases and 50 had liver and peritoneal metastases. Complete cytoreduction was achieved in 78% of patients with isolated liver metastases and 56% of those with liver and peritoneal metastases (p = 0.002). After complete cytoreduction, median overall survival (OS) was 11.5 years for isolated liver metastases and 11.2 years for liver and peritoneal metastases (p = 0.10), and relief of carcinoid syndrome was ≥ 97% in both groups. After incomplete cytoreduction with debulking of > 90% of hepatic disease and/or closing Lyon score of 1-2, median OS was 6.4 years for isolated liver metastases and 7.1 years for liver and peritoneal metastases (p = 0.12).

CONCLUSIONS

Patients with siNETs metastatic to both the liver and peritoneum have favorable outcomes after aggressive surgical cytoreduction, with the best outcomes observed after complete cytoreduction. Therefore, the presence of peritoneal metastases should not by itself preclude surgical cytoreduction in this population.

Presacral Neuroendocrine Neoplasms: A Multi-site Review of Surgical Outcomes

INTRODUCTION

Presacral neuroendocrine neoplasms (PNENs) are rare tumors, with limited data on management and outcomes.

METHODS

A retrospective review of institutional medical records was conducted to identify all patients with PNENs between 2008 and 2022. Data collection included demographics, symptoms, imaging, surgical approaches, pathology, complications, and long-term outcomes.

RESULTS

Twelve patients were identified; two-thirds were female, averaging 44.8 years of age, and, for the most part, presenting with back pain, constipation, and abdominal discomfort. Preoperative imaging included computed tomography scans and magnetic resonance images, with somatostatin receptor imaging and biopsies being common. Half of the patients had metastatic disease on presentation. Surgical approach varied, with anterior, posterior, and combined techniques used, often involving muscle transection and coccygectomy. Short-term complications affected one-quarter of patients. Pathologically, PNENs were mainly well-differentiated grade 2 tumors with positive synaptophysin and chromogranin A. Associated anomalies were common, with tail-gut cysts prevalent. Mean tumor diameter was 6.3 cm. Four patients received long-term adjuvant therapy. Disease progression necessitated additional interventions, including surgery and various chemotherapy regimens. Skeletal, liver, thyroid, lung, and pancreatic metastases occurred during follow-up, with no mortality reported. Kaplan-Meier analysis showed a 5-year local recurrence rate of 23.8%, disease progression rate of 14.3%, and de novo metastases rate of 30%.

CONCLUSION

The study underscores the complex management of PNENs and emphasizes the need for multicenter research to better understand and manage these tumors. It provides valuable insights into surgical outcomes, recurrence rates, and overall survival, guiding future treatment strategies for PNEN patients.

Evaluation of a blood miRNA/mRNA signature to follow-up Lu-PRRT therapy for G1/G2 intestinal neuroendocrine tumors

Background

177Lu-oxodotreotide peptide receptor therapy (LuPRRT) is an efficient treatment for midgut neuroendocrine tumors (NETs) of variable radiological response. Several clinical, biological, and imaging parameters may be used to establish a relative disease prognosis but none is able to predict early efficacy or toxicities. We investigated expression levels for mRNA and miRNA involved in radiosensitivity and tumor progression searching for correlations related to patient outcome during LuPRRT therapy.

Methods

Thirty-five patients received LuPRRT for G1/G2 midgut NETs between May 2019 and September 2021. Peripheral blood samples were collected prior to irradiation, before and 48 h after the second and the fourth LuPRRT, and at 6-month follow-up. Multiple regression analyses and Pearson correlations were performed to identify the miRNA/mRNA signature that will best predict response to LuPRRT.

Results

Focusing on four mRNAs and three miRNAs, we identified a miRNA/mRNA signature enabling the early identification of responders to LuPRRT with significant reduced miRNA/mRNA expression after the first LuPRRT administration for patients with progressive disease at 1 year (p < 0.001). The relevance of this signature was reinforced by studying its evolution up to 6 months post-LuPRRT. Moreover, nadir absolute lymphocyte count within the first 2 months after the first LuPRRT administration was significantly related to low miRNA/mRNA expression level (p < 0.05) for patients with progressive disease.

Conclusion

We present a pilot study exploring a miRNA/mRNA signature that correlates with early hematologic toxicity and therapeutic response 12 months following LuPRRT. This signature will be tested prospectively in a larger series of patients.

Neuroendocrine carcinoma of the common hepatic duct coexisting with distal cholangiocarcinoma: A case report and review of literature

BACKGROUND

Neuroendocrine carcinoma (NEC) of the extrahepatic bile duct is very rare, and the treatment and prognosis are unclear. Herein, we report the case of a middle-aged female with primary large cell NEC (LCNEC) of the common hepatic duct combined with distal cholangiocarcinoma (dCCA). Additionally, after a review of the relevant literature, we summarize and compare mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) and pure NEC to provide a reference for selecting the appropriate treatment and predicting the prognosis of this rare disease.

CASE SUMMARY

A 62-year-old female presented to the hospital due to recurrent abdominal pain for 2 months. Physical examination showed mild tenderness in the upper abdomen and a positive Courvoisier sign. Blood tests showed elevated liver transaminase and carbohydrate antigen 199 levels. Imaging examination revealed a 1-cm tumour in the middle and lower segments of the common bile duct. Pancreaticoduodenectomy + lymph node dissection was performed, and hepatic duct tumours were unexpectedly found during surgery. Pathology suggested poorly differentiated LCNEC (approximately 0.5 cm × 0.5 cm × 0.4 cm), Ki-67 (50%), synaptophysin+, and chromogranin A+. dCCA pathology suggested moderately differentiated adenocarcinoma. The patient eventually developed lymph node metastasis in the liver, bone, peritoneum, and abdominal cavity and died 24 months after surgery. Gene sequencing methods were used to compare gene mutations in the two primary bile duct tumours.

CONCLUSION

The prognosis of MiNEN and pure NEC alone is different, and the selection of treatment options needs to be differentiated.

Incidence, mortality and survival of Merkel cell carcinoma: a systematic review of population-based studies

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that most commonly occurs in ultraviolet-exposed body sites. The epidemiology of MCC in different geographies and populations is not well characterized.

OBJECTIVES

The objective of this systematic review is to summarize evidence on the incidence, mortality and survival rates of MCC from population-based studies.

METHODS

We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from database inception to 6 June 2023. No geographic, age or date exclusions were applied. We included population-based studies of MCC that reported the incidence, survival or mortality rate, and also considered systematic reviews. A data-charting form was created and validated to identify variables to extract. Two reviewers then independently charted the data for each included study with patient characteristics, and estimates of incidence rate, mortality rate, and survival rate and assessed the quality of included studies using the Joanna Briggs Institute Checklist for Prevalence studies, Newcastle-Ottawa Scale and Assessment of Multiple Systematic Reviews. We abstracted age-, sex-, stage- and race-stratified outcomes, and synthesized comparisons between strata narratively and using vote counting. We assessed the certainty of evidence for those comparisons using the Grading of Recommendations, Assessments, Developments and Evaluations framework.

RESULTS

We identified 11 472 citations, of which 52 studies from 24 countries met our inclusion criteria. Stage I and the head and neck were the most frequently reported stage and location at diagnosis. The incidence of MCC is increasing over time (high certainty), with the highest reported incidences reported in southern hemisphere countries [Australia (2.5 per 100 000); New Zealand (0.96 per 100 000) (high certainty)]. Male patients generally had higher incidence rates compared with female patients (high certainty), although there were some variations over time periods. Survival rates varied, with lower survival and/or higher mortality associated with male sex (moderate certainty), higher stage at diagnosis (moderate-to-high certainty), older age (moderate certainty), and immunosuppression (low-to-moderate certainty).

CONCLUSIONS

MCC is increasing in incidence and may increase further given the ageing population of many countries. The prognosis of MCC is poor, particularly for male patients, those who are immunosuppressed, and patients diagnosed at higher stages or at an older age.

Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

PURPOSE

To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice.

RESULTS

Eight randomized controlled trials met the inclusion criteria for the systematic review.

RECOMMENDATIONS

Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)-positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Survival Trends in Patients with Small Intestinal Neuroendocrine Tumours-A Cohort Study in Central Norway

Improved surgical resection and oncological treatment, or an earlier diagnosis may increase survival in small intestinal neuroendocrine tumours (SI-NETs), but only few studies have examined survival trends. We aimed to examine the trend in overall survival and associated factors in SI-NET patients. All patients with SI-NETs at a regional hospital from June 2005 to December 2021 (n = 242) were identified, and the cohort was divided in half, constituting a first period (until November 2012) and a second period (from November 2012). Disease and treatment characteristics, including European Neuroendocrine Tumour Society (ENETS) stage, surgery, oncological treatment and survival, were recorded. The majority (n = 205 (84.7%)) were treated surgically and surgery was considered curative in 137 (66.8%) patients. Median survival was longer in the second period (9.0 years 95% CI 6.4-11.7 in the first period vs. median not reached in the second period, p = 0.014), with 5-year survival rates of 63.5% and 83.5%, respectively. ENETS stage and oncological treatment did not differ between the periods, but factors associated with surgical quality, such as lymph node harvest and resection of multiple SI-NETs, were significantly higher in the second period. Age, ENETS stage, time period and tumour resection were independently associated with survival in a multivariate analysis.