A population-based study of outcomes in patients with gastrointestinal neuroendocrine tumours

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.

Is Endoscopic Resection Essential for Patients with Type 1 Gastric Neuroendocrine Tumor?

Background: The gastric neuroendocrine tumor (g-NET) is now more frequently diagnosed due to the widespread use and advancement of endoscopy. In our study, we aimed to discuss the superiority, if any, between the watch-and-wait approach and endoscopic treatment methods for the controversial management of type 1 g-NETs, as well as to evaluate their long-term outcomes. Materials and Methods: The data of 81 patients who underwent gastroscopy due to complaints related to the upper gastrointestinal system and were diagnosed with type 1 g-NET as a result of biopsy taken from suspicious stomach lesions were examined. After exclusion criteria, 48 patients were included in the study. Patients were categorized into two groups: the watch-and-wait group, where no invasive procedure was performed, and the group that underwent any form of endoscopic resection. Results: Thirty-seven patients were followed up regularly without any treatment. Eleven patients were followed up after endoscopic resection (endoscopic submucosal dissection-endoscopic mucosal resection). Endoscopic resection was performed in 5 of 37 patients with tumor size <10 mm and in 6 of 11 patients with tumor size between 10 and 20 mm. The median follow-up duration for all patients was 5 years, during which no instances of metastasis, tumor progression, or mortality were observed in any patient, regardless of whether they underwent endoscopic resection or not. Conclusion: This outcome prompts a questioning of the necessity for invasive treatment methods such as endoscopic resection, which comes with a relatively high cost and the potential for complications, in this particular patient group.

A novel nomogram and risk stratification system predicting the cancer-specific survival of patients with gastric neuroendocrine carcinoma: a study based on SEER database and external validation

BACKGROUND

Gastric neuroendocrine carcinoma (GNEC) is a rare histology of gastric cancer. The retrospective study was designed to construct and validate a nomogram for predicting the cancer-specific survival (CSS) of postoperative GNEC patients.

METHODS

Data for 28 patients from the Hangzhou TCM Hospital were identified as the external validation cohort. A total of 1493 patients were included in the SEER database and randomly assigned to the training group (1045 patients) and internal validation group (448 patients). The nomogram was constructed using the findings of univariate and multivariate Cox regression studies. The model was evaluated by consistency index (C-index), calibration plots, and clinical net benefit. Finally, the effect between the nomogram and AJCC staging system was compared by net reclassification index (NRI) and integrated discrimination improvement (IDI).

RESULTS

Age, gender, grade, T stage, N stage, metastasis, primary site, tumor size, RNE, and chemotherapy were incorporated in the nomogram. The C-indexes were 0.792 and 0.782 in the training and internal verification sets. The 1-, 3-, and 5-year CSS predicted by the nomogram and actual measurements had good agreement in calibration plots. The 1-, 3-, and 5-year NRI were 0.21, 0.29, and 0.37, respectively. The 1-, 3-, and 5-year IDI values were 0.10, 0.12, and 0.13 (P < 0.001), respectively. In 1-, 3-, and 5-year CSS prediction using DCA curves, the nomogram outperformed the AJCC staging system. The nomogram performed well in both the internal and external validation cohorts.

CONCLUSION

We developed and validated a nomogram to predict 1-, 3-, and 5-year CSS for GNEC patients after surgical resection. This well-performing model could help doctors enhance the treatment plan.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for colorectal neuroendocrine tumours

This ENETS guidance paper, developed by a multidisciplinary working group, provides an update on the previous colorectal guidance paper in a different format. Guided by key clinical questions practical advice on the diagnosis and management of neuroendocrine tumours (NET) of the caecum, colon, and rectum is provided. Although covered in one guidance paper colorectal NET comprises a heterogeneous group of neoplasms. The most common rectal NET are often small G1 tumours that can be treated by adequate endoscopic resection techniques. Evidence from prospective clinical trials on the treatment of metastatic colorectal NET is limited and discussion of patients in experienced multidisciplinary tumour boards strongly recommended. Neuroendocrine carcinomas (NEC) and mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) are discussed in a separate guidance paper.

Characteristics and treatment results of patients with gastroenteropancreatic neuroendocrine tumors in a tertiary care centre

BACKGROUND

Gastroenteropancreatic Neuroendocrine tumors (GEP-NET) are rare neoplasms with limited reported data from the Middle East. Our study aims to report the clinicopathological feature, treatment patterns, and survival outcomes of patients with GEP-NET from our part of the world.

METHODS

Medical records of patients diagnosed with GEP-NET between January 2011 and December 2016 at a single center in Saudi Arabia were reviewed retrospectively, and complete clinicopathological and treatment data were collected. Patients' survival was estimated by the Kaplan-Meier method.

RESULTS

A total of 72 patients were identified with a median age of 51 years (range 27-82) and male-to-female ratio of (1.1). The most common tumor location was the pancreas (29.1%), followed by small bowel (25%), stomach (12.5%), rectum (8.3%), colon (8.3%), and appendix (6.9%). Forty-one patients (57%) had well-differentiated grade (G)1, 21 (29%) had G2, and 4 (6%) had G3. In five patients, the pathology was neuroendocrine carcinoma and in one it could not be classified. 54.2% of the patients were metastatic at diagnosis. Forty-two patients underwent surgical resection as primary management while 26 underwent systemic therapy, three patients were put on active surveillance, and one was treated endoscopically with polypectomy. The 5-year overall survival and progression-free survivals were 77.2% and 49%, respectively, for the whole group. Patients with G1 and 2 disease, lower Ki-67 index, and surgically treated as primary management had significantly better survival outcomes.

CONCLUSION

Our study suggests that the most common tumor locations are similar to western reported data. However, there seems to be a higher incidence of metastatic disease at presentation than in the rest of the world.

Bouveret Syndrome simultaneous with an incidental solitary Gastric Neuroendocrine Tumor in a 44-year-old female - A Case Report

Bouveret Syndrome (BS) is a rare type of gallstone ileus, where a gallstone passes via a cholecystoduodenal fistula and causes gastric outlet obstruction. It comprises 0.3-0.5% of cholelithiasis complications. It primarily affects females with an average incidence age of 74 years. Gastric Neuroendocrine Tumors (G-NETs) make up merely 2% of all forms of gastric neoplasia and are known to be an extremely rare occurrence. Their annual incidence is estimated to be one to two per 1 million individuals, and they comprise 8.7% of all known neuroendocrine neoplasia of the gastrointestinal system.

Case presentation

We present the case of a 44-year-old Middle Eastern female who presented to the clinic due to multiple episodes of food containing biliary nonprojectile emesis accompanied by epigastric pain. Preoperative radiological workup revealed a Bezoar blocking the gastric outlet and a G-NET in the mucosal layer of the stomach.

Clinical discussion

Surgical intervention consisted of excising the impacted calculus to relieve the existing gastric outlet obstruction simultaneous to performing an uncut Roux-en-Y to treat the G-NET condition. The patient underwent complete recovery.

Conclusion

BS is an extremely rare form of gallstone ileus and gastric outlet obstruction. Its clinical presentation is nonspecific and results in misdiagnosis. Additionally, it is rare to occur in our patient's age group. NETs are also profoundly rare forms of neoplasia. To the best of our knowledge, no previous cases of simultaneous BS and G-NET have been documented. Therefore, clinical awareness should be raised to timely implement the necessary therapeutic interventions.

Inflammation Related to Obesity in the Etiopathogenesis of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare neoplasms, which, due to their heterogeneous nature, non-specific symptoms, and lack of specific tumor markers pose many diagnostic and clinical challenges. In recent years, the effectiveness of GEP-NEN diagnosis has increased, which is probably associated with the greater availability of diagnostic tests and the cooperation of many experienced specialists in various scientific disciplines. In addition to the possible genetic etiology, the cause of GEP-NET development is not fully understood. Inflammation and obesity are known risks that contribute to the development of many diseases. Chronic inflammation accompanying obesity affects the hormonal balance and cell proliferation and causes the impairment of the immune system function, leading to neoplastic transformation. This review explores the role of inflammation and obesity in GEP-NETs. The exact mechanisms inducing tumor growth are unknown; however, the profile of inflammatory factors released in the GEP-NET tumor microenvironment is responsible for the progression or inhibition of tumor growth. Both the excess of adipose tissue and the impaired function of the immune system affect not only the initiation of cancer but also reduce the comfort and lifetime of patients.

Long-term survival in patients with gastroenteropancreatic neuroendocrine neoplasms: A population-based study

BACKGROUND

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) comprise a group of rare malignant tumours with heterogeneous behaviour. This study aimed to assess long-term survival and prognostic factors associated with survival, in order to optimise counselling.

PATIENTS AND METHODS

This population-based study included all GEP-NENs diagnosed between 1989 and 2016 in the Netherlands, selected from the Netherlands Cancer Registry. Overall survival (OS) and relative survival (RS) were calculated. A Cox Proportional Hazard analysis was used to identify prognostic factors (gender, age, tumour stage, location and treatment) for OS. Analyses were stratified by metastatic disease status and tumour grade.

RESULTS

In total, 9697 patients were included. In grade 1, 2 and 3 non-metastatic GEP-NENs (N = 6544), 5-year OS and RS were 81% and 88%, 78% and 83%, and 26% and 30%, respectively. In grade 1 non-metastatic GEP-NENs 10-year OS and RS were 68% and 83%. In grade 1, 2 and 3 metastatic GEP-NENs (N = 3153), 5-year OS and RS rates were 47% and 52%, 38% and 41%, and 5% and 5%, respectively. The highest (relative) survival rates were found in appendicular and rectal NENs, demonstrating 10-year OS and RS of 87% and 93%, and 81% and 95%, respectively.

CONCLUSIONS

These long-term follow-up data demonstrate significant differences in survival for different grades, tumour stage, and primary origin of GEP-NENs, with the most favourable overall and RS rates in patients with non-metastatic grade 1 appendicular and rectal NENs. This study demonstrates unique long-term OS and RS rates using combined stratification by tumour site, grade and stage.

The overriding role of surgery and tumor grade for long-term survival in patients with gastroenteropancreatic neuroendocrine neoplasms: A population-based cohort study

Background

Gastroenteropancreatic neuroendocrine neoplasms (GEP‐NENs) comprise a heterogeneous disease group. Factors that affect long‐term survival remain uncertain. Complete population‐representative cohorts with long‐term follow‐up are scarce.

Aim

To evaluate factors of importance for the long‐term survival.

Methods and results

An Observational population‐based study on consecutive GEP‐NEN patients diagnosed from 2003 to 2013, managed according to national guidelines. Univariable and multivariable survival analyses were performed to evaluate overall survival (OS) and to identify independent prognostic factors. One hundred ninety eligible patients (males, 58.9%) (median age, 60.0 years; range, 10.0–94.2 years) were included. The small bowel, appendix, and pancreas were the most common tumor locations. The World Health Organization (WHO) tumor grade 1–3 distributions varied according to the primary location and disease stage. Primary surgery with curative intent was performed in 66% of the patients. The median OS of the study population was 183 months with 5‐ and 10‐year OS rates of 66% and 57%, respectively. Only age, WHO tumor grade, and primary surgical treatment were independent prognostic factors for OS.

Conclusion

The outcomes of GEP‐NEN patients are related to several factors including age and primary surgical treatment. WHO tumor grading, based on the established criteria, should be routine in clinical practice. This may improve clinical decision‐making and allow the comparison of outcomes among different centers.

Gastric neuroendocrine tumor: A practical literature review

Gastric neuroendocrine tumors are gastric neoplasms originating from enterochromaffin type cells and are inserted in a larger group, named gastroenteropancreatic neuroendocrine tumors. They are considered rare and variable in terms of their clinical, morphological and functional characteristics and may be indolent or aggressive. They are classified into types I, II and III, according to their pathophysiology, behavior and treatment. Their diagnosis occurs, in most cases, incidentally during upper digestive endoscopies, presenting as simple gastric polyps. Most cases (type I and type II) are related to hypergastrinemia, can be multiple and are treated by endoscopic resection, whenever possible. The use of somatostatin analogs for tumor control may be one of the options for therapy, in addition to total or subtotal gastrectomy for selected cases. Adjuvant chemotherapy is only reserved for poorly differentiated neuroendocrine carcinomas. Although rare, gastric neuroendocrine tumors have an increasing incidence over the years, therefore deserving more comprehensive studies on its adequate treatment. The present study reviews and updates management recommendations for gastric neuroendocrine tumors.

Trends of incidence and prognosis of gastric neuroendocrine neoplasms: a study based on SEER and our multicenter research

BACKGROUND

To investigate the recent epidemiological trends of gastric neuroendocrine neoplasms (GNENs) and establish a new tool to estimate the prognosis of gastric neuroendocrine carcinoma (GNEC) and gastric neuroendocrine tumor (GNET).

METHODS

Nomograms were established based on a retrospective study on patients diagnosed with GNENs from 1975 to 2016 in Surveillance, Epidemiology and End Results database. External validation was performed among 246 GNENs patients in Jiangsu province to verify the discrimination and calibration of the nomograms.

RESULTS

The age-adjusted incidence of GNENs has increased from 0.309 to 6.149 per 1,000,000 persons in the past 4 decades. Multivariate analysis indicated independent prognostic factors for both GNEC and GNET including age, distant metastasis and surgical intervention (P < 0.05). In addition, T, N staging and grade were significantly associated with survival of GNEC, while size was a predictor for GNET (P < 0.05). The C-indexes of the nomograms were 0.840 for GNEC and 0.718 for GNET, which were higher than those of the 8th AJCC staging system (0.773 and 0.599). Excellent discrimination was observed in the validation cohorts (C-index of nomogram vs AJCC staging for GNEC: 0.743 vs 0.714; GNET: 0.945 vs 0.927). Survival rates predicted by nomograms were close to the actual survival rates in the calibration plots in both training and validation sets.

CONCLUSIONS

The incidence of the GNENs is increasing steadily in the past 40 years. We established more excellent nomograms to predict the prognosis of GNENs than traditional staging system, helping clinicians to make tailored decisions.

Treatment Patterns and Survival among Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumours in Sweden - a Population-based Register-linkage and Medical Chart Review Study

Background: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are neoplasms derived from the endocrine system in the gastrointestinal tract and pancreas. Treatment options include surgery; pharmacological treatments like somatostatin analogues (SSA), interferon alpha, molecular targeted therapy and chemotherapy; and peptide receptor radionuclide therapy.

The objective of this study was to describe treatment patterns and survival among patients with metastatic GEP-NET grade 1 or 2 in Sweden.

Methods: Data was obtained via linkage of nationwide registers. Patients diagnosed with metastatic GEP-NET grade 1 or 2 in Sweden between 2005 and 2013 were included (n=811; National population). In addition, medical chart review was performed for the subpopulation diagnosed at Sahlgrenska University Hospital, Gothenburg (n=127; Regional population). Treatment patterns, including treatment sequences, and overall survival were assessed.

Results: Most patients had small intestinal NET (76%). In the regional population, 72% had grade 1 tumours; 50% had functioning tumours. The two most common first-line treatments were surgery (57%) and SSA (25%). After first-line surgery, 46% received SSA, while 40% had no further treatment. After first-line SSA, 52% received surgery, while 27% had no further treatment. Overall median survival time from date of diagnosis was 7.0 years (95% CI 6.2-not reached). Among patients with distant metastases, pancreatic NET (vs. small intestinal NET) was associated with poorer survival (HR 1.9; 95% CI 1.1-3.3), as were liver metastases (HR 3.2; 95% CI 1.5-7.0).

Conclusions: First-line surgery was typically followed by SSA or no further treatment. Among patients with distant metastases, pancreatic NET or liver metastases were associated with a poorer survival.

Development of predictive prognostic nomogram for NECs of rectum on population-based exploration

AIM

We aim to investigate the clinical characteristics of the rectal NECs and the prognosis-related factors and construct a nomogram for prognosis prediction.

METHODS

The data of 41 patients and 1028 patients with rectal NEC were retrieved respectively from our institution and SEER database. OS or PFS were defined as the major study outcome. Variables were compared by Chi2 test, t-test when appropriate. Kaplan-Meier analysis with log-rank test was used for survival analysis and the cox regression analysis were applied. The nomogram integrating risk factors for predicting OS was constructed by R to achieve superior discriminatory ability. Predictive utility of the nomogram was determined by concordance index (C-index) and calibration curve.

RESULTS

In the univariate and multivariate analysis, tumor differentiation, N stage, M stage and resection of primary site were identified as independent prognostic indicators. The linear regression relationship was found between the value of Ki-67 index and the duration of OS (P<0.05). Furthermore, the independent prognostic factors were added to formulate prognostic nomogram. The constructed nomogram showed good performance according to the C-index.

CONCLUSIONS

Contrary to WHO classification guideline, we found that the rectal NEC disease are heterogeneous and should be divided as different categories according to the pathological differentiation. Besides, the nomogram formulated in this study showed excellent discriminative capability to predict OS for those patients. More advanced predictive model for this disease is required to assist risk stratification via the formulated nomogram.

Visceral Obesity and Metabolic Syndrome Are Associated with Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors

The determinants for gastroenteropancreatic neuroendocrine tumors (GEP-NET) recent burden are matters of debate. Obesity and metabolic syndrome (MetS) are well established risks for several cancers even though no link with GEP-NETs was yet established. Our aim in this study was to investigate whether well-differentiated GEP-NETs were associated with obesity and MetS. Patients with well-differentiated GEP-NETs (n = 96) were cross-matched for age, gender, and district of residence with a control group (n = 96) derived from the general population in a case-control study. Patients presented gastro-intestinal (75.0%) or pancreatic (22.9%) tumors, grade G1 (66.7%) or G2 (27.1%) with localized disease (31.3%), regional metastasis (16.7%) or distant metastasis (43.8%) at diagnosis, and 45.8% had clinical hormonal syndromes. MetS was defined according to Joint Interim Statement (JIS) criteria. Well-differentiated GEP-NETs were associated with MetS criteria as well as the individual components' waist circumference, fasting triglycerides, and fasting plasma glucose (p = 0.003, p = 0.002, p = 0.011 and p < 0.001, respectively). The likelihood of the association was higher when the number of individual MetS components was greater than four. MetS and some individual MetS components including visceral obesity, dyslipidemia, and increased fasting glucose are associated with well-differentiated GEP-NET. This data provides a novel insight in unraveling the mechanisms leading to GEP-NET disease.

Incidence trend and conditional survival estimates of gastroenteropancreatic neuroendocrine tumors: A large population-based study

Given the rarity and indolent clinical course of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), conditional survival might be the most suitable parameter for cancer survivors who wish to receive accurate prognostic information during follow-up. We have explored the updated incidence trend and the conditional survival of patients with GEP-NETs. Incidence trends from 2000 to 2014 were determined through an assessment of patients in the SEER cancer registry. Patients diagnosed between 1988 and 2011 were included in the conditional survival analysis, and the 3-year conditional cancer-specific survival (CCS3) was computed. The incidence of GEP-NETs, which is far higher than the incidence of many malignant tumors, is still increasing steadily (annual percentage change = 4.4). The risk of death from NETs is dynamic over time, and most deaths occur in the first 3 years after diagnosis. Patients with gastric, rectal, or appendiceal NETs hardly exhibit any excess mortality (CCS3 > 95%) given that they have already survived until a defined time-point within 10 years. The initial difference between each age group basically disappeared with an extension of the survival time since the initial diagnosis of gastric, appendiceal, or rectal NETs, but the difference persisted for tumors at other sites. Although patients with advanced-stage or higher-grade tumors have a worse survival at diagnosis than patients with early-stage or lower-grade tumors, the difference diminishes and might even disappear over time. For GEP-NETs that are rare but exhibit slow growth, clinically relevant variations in conditional survival were observed based on the time since diagnosis. Therefore, conditional survival can serve as a guideline that can be used by cancer survivors to plan their future and doctors to plan surveillance schedules.

Global burden of neuroendocrine tumors and changing incidence in Kentucky

Background

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

Methods

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

Results

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

Conclusions

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