JNETS clinical practice guidelines for gastroenteropancreatic neuroendocrine neoplasms: diagnosis, treatment, and follow-up: a synopsis

Long-term survival with multimodal treatment including conversion surgery for locally advanced esophageal neuroendocrine carcinoma: A case report

BACKGROUND

Esophageal neuroendocrine carcinoma (NEC), a rare and aggressive malignancy with a poor prognosis, is often diagnosed at an advanced stage. The optimal treatment strategy for locally advanced and recurrent esophageal NEC remains unclear, and conversion surgery has only been reported for a few cases. Herein, we present the case of a 66-year-old male with locally advanced esophageal NEC initially diagnosed as squamous cell carcinoma.

CASE SUMMARY

The patient underwent induction chemotherapy with docetaxel, cisplatin, and 5-fluorouracil, followed by conversion surgery, including subtotal esophagectomy, three-field lymph node dissection, and distal pancreatectomy with splenectomy, due to infiltration of the pancreas by the No. 11p lymph node. Postoperative pathological findings revealed a large cell-type NEC without a squamous cell carcinoma component, suspected to be a mixed neuroendocrine/non-neuroendocrine neoplasm. Hepatic metastasis was diagnosed within one month of surgery. Despite the administration of four courses of irinotecan + cisplatin chemotherapy, the treatment effect was considered a ‘progressive disease’. After a multidisciplinary discussion, the patient underwent partial liver resection, followed by second-line chemotherapy with amrubicin. The patient achieved three-year survival with no new recurrence.

CONCLUSION

This case highlights the potential of multimodal treatment for long-term survival in advanced esophageal NEC.

Non-hypervascular pancreatic neuroendocrine neoplasms differentiation from CA19-9 negative pancreatic ductal adenocarcinomas based on contrast CT: A large sample series

PROPOSE

This study aims to evaluate the effectiveness of contrast-enhanced computed tomography (CT) in distinguishing non-hypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs) with a normal serum level of carbohydrate antigen 19-9 (CA19-9) levels.

METHODS

This retrospective study included 134 patients with pathologically confirmed non-hypervascular PNENs and 128 patients with CA19-9-negative PDACs, all of whom underwent contrast-enhanced CT prior to surgery between January 2015 and March 2024. Following independent evaluation by two radiologists, qualitative features from both groups were extracted in the arterial and portal venous phase and subsequently compared using univariate and multivariate analysis.

RESULTS

Patients with CA19-9 negative PDACs were significantly older than those with non-hypervascular PNENs (p < 0.001), and the majority of PDACs were located in the head of the pancreas (p < 0.01).Univariate analysis showed that non-hypervascular PNENs exhibited a higher frequency of well-defined tumor margins (p < 0.001) and calcification (p = 0.032) and a lower frequency of local invasion (p < 0.001), peripancreatic vascular invasion (p = 0.001), intra- or extrahepatic bile duct dilatation (p < 0.001), distal main pancreatic duct dilatation (p < 0.001), regional lymphadenopathy (p < 0.001) and tumor homogeneity (p < 0.001) when compared to CA19-9 negative PDACs. Multivariate analysis identified the absence of local invasion (Odds Ratio (OR) = 0.233; 95 % Confidence Internals (95 % CI):0.114-0.476; p < 0.001), absence of peripancreatic vascular invasion (OR = 0.434; 95 % CI:0.217-0.870; p = 0.019), a normal distal main pancreatic duct diameter (OR = 0.398; 95 % CI:0.202-0.785; p = 0.008), absence of regional lymphadenopathy (OR = 0.455; 95 % CI:0.238-0.870; p = 0.017) and tumor heterogeneity (OR = 0.240; 95 % CI:0.126-0.456; p < 0.001) as significant predictors of non-hypervascular PNENs. The area under the receiver operating characteristic curve for the radiological feature model was 0.829 based on logistic regression.

CONCLUSIONS

Qualitative features in contrast-enhanced CT images could be beneficial in differentially diagnosing non-hypervascular PNENs and CA19-9 negative PDACs.

Last decade of advances in gastric neuroendocrine tumors: Innovations, challenges, and future directions

BACKGROUND

Gastric neuroendocrine tumors (G-NETs) are rare tumors originating from enterochromaffin-like cells, with an incidence of 0.4 per 100000 annually. There are three main types: (1) Type I, linked to chronic atrophic gastritis and hypergastrinemia, makes up 75%–80% of G-NETs; (2) Type II, associated with Zollinger-Ellison syndrome (ZES) and multiple endocrine neoplasia, comprises 5%; and (3) Type III, sporadic tumors with a higher metastatic potential, accounting for 15%–25%. Diagnosis involves endoscopy, biopsy, and histological examination. Additional methods include serum gastrin testing, immunohistochemistry, and imaging techniques such as computer tomography or magnetic resonance imaging for detecting metastasis. Type I treatment usually involves endoscopic resection (ER), with surgical resection for recurrence. Somatostatin analogs (SSAs) can reduce tumor size, and the prognosis is generally excellent. Type II treatment centers on surgical removal of the gastrinoma, with ER for smaller lesions and SSAs for symptom management. Type III requires surgical resection (partial or total gastrectomy) with lymph node dissection, and possibly chemotherapy. This type has a worse prognosis due to its aggressive nature. Emerging treatments like Peptide Receptor Radionuclide Therapy are promising for advanced cases, and ongoing research into immunotherapies is expanding future treatment options. Regular endoscopic follow-up is crucial to monitor for recurrence or metastasis across all types. Our literature review explores the current perspectives on G-NETs and highlights the importance of further research to improve diagnostic precision and treatment, particularly for those associated with less favorable cases.

AIM

To improve diagnostic precision and treatment, particularly for those associated with less favorable cases.

METHODS

A systematic search was conducted in PubMed, Scopus, and Web of Science until September 2024. Two independent reviewers screened titles, abstracts, and full texts for eligibility based on G-NET treatment in adults. Eligible studies included cohort studies, clinical trials, case series, and case reports, while in vitro, pediatric, and non-English studies were excluded. Relevant data were extracted independently, and disagreements were resolved through discussion. Study quality was assessed using appropriate tools.

RESULTS

G-NETs are rare, classified into three types: (1) Type I; (2) Type II; and (3) Type III. Type I G-NETs, often associated with chronic atrophic gastritis, are typically slow-growing and low-grade, with favorable outcomes following surgical resection. Type II G-NETs arise in hypergastrinemia conditions like multiple endocrine neoplasia and ZES, showing moderate malignancy risk. Type III G-NETs, the most aggressive and least common, present with distant metastases and poor prognosis. Diagnosis relies on endoscopy, imaging, and biomarkers like chromogranin A. Treatment varies by type, ranging from ER to aggressive surgery and chemotherapy for advanced cases. Regular follow-up is essential to monitor recurrence, particularly for type III G-NETs.

CONCLUSION

G-NETs require tailored diagnosis and treatment based on type and stage. Types I and II generally have better prognosis, while types III and IV are linked to poorer outcomes due to invasion and metastasis. Treatment strategies vary from ER for type I to extensive surgery for type III. Emerging therapies, like somatostatin analogs and peptide-receptor radionuclide therapies, show promise in advanced cases. Further research is essential to improve early diagnosis and treatment, particularly for high-risk lesions.

Current status of endoscopic resection for small rectal neuroendocrine tumors

Rectal neuroendocrine tumor (rNET) is an indolent malignancy often detected during colonoscopy screening. The incidence of rNET has increased approximately 10-fold over the past 30 years. Most rNETs detected during screening endoscopy are small, measuring < 10 mm. Current guidelines recommend endoscopic resection for small, well-differentiated rNET using modified endoscopic submucosal resection (mEMR) or endoscopic submucosal dissection. However, the optimal endoscopic treatment method remains uncertain. This paper summarizes the evidence on mEMR with submucosal stretching, mEMR without submucosal stretching, endoscopic submucosal dissection and endoscopic full-thickness resection. Given that rNETs often exhibit submucosal invasion, achieving adequate resection depth is crucial to ensure histological complete resection. mEMR with submucosal stretching appears favorable due to its high rate of histological complete resection, safety and convenience. Risk factors associated with lymph node and distant metastases are also discussed. A treatment algorithm is proposed to facilitate clinical decision-making.

Emerging innovations in theranostics for pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) often overexpress somatostatin receptor type 2 (SSTR2), making them ideal targets for theranostics, which integrates molecular imaging with targeted radionuclide therapy. 177Lu-DOTATATE significantly extends progression-free survival (22.8 vs. 8.5 months) compared to octreotide LAR. Despite these advances, challenges remain, including treatment resistance and long-term toxicities. In this review, we explore advancements in specialized imaging techniques, rationale combination strategies, and exploring next-generation radiopharmaceuticals.

Rare rectal elastofibroma: diagnostic challenges and case report

Elastofibroma (EF) is a rare soft tissue tumor that typically occurs in the scapular region, with its occurrence in the rectum being extremely uncommon. In this report, we present a case of rectal EF in a 72-year-old female, which was definitively diagnosed through histopathology, immunohistochemistry, and special staining analyses. This case emphasizes the diagnostic challenges posed by rectal EF and underscores the necessity of histopathological and immunohistochemical assessment in distinguishing it from other spindle cell neoplasms, particularly when imaging findings are inconclusive.

Treatment of Pancreatic Neuroendocrine Tumors: Beyond Traditional Surgery and Targeted Therapy

Pancreatic neuroendocrine tumors (PNETs) are a rare subset of pancreatic neoplasms with diverse biological behavior and clinical presentations. Traditional treatment approaches, such as surgery and targeted therapies, have significantly improved outcomes. However, advancements in molecular biology, immunotherapy, and minimally invasive techniques have ushered in a new era of treatment possibilities. This manuscript explores the emerging modalities in PNET management, emphasizing the need for a multidisciplinary approach tailored to individual patient profiles.

Primary Neuroendocrine Carcinoma of the Anal Canal with Cancer Genome Profiling

Primary neuroendocrine carcinoma (NEC) of the anal canal is a rare, highly malignant tumor with a poor prognosis. Despite the standard first-line treatment with etoposide or irinotecan combined with cisplatin, effective second-line therapies are lacking. In 2019, Japan approved cancer genome profiling (CGP) tests for solid tumors to enhance genomic understanding. We present the case of a 79-year-old woman with NEC of the anal canal, treated with etoposide, carboplatin, and amrubicin. As Post-standard therapy, CGP suggested pemigatinib, a tyrosine kinase inhibitor; however, the patient died before receiving it. This case highlights the potential of personalized medicine to improve outcomes in such cases.

Epidemiology, prognostic factors, and survival analysis in small cell esophageal carcinoma: A population-based study with external validation

Small cell esophageal carcinoma (SCEC) is a poorly differentiated esophageal neuroendocrine neoplasm with a poor prognosis. This study aimed to explore the factors and treatment approaches influencing the prognosis of SCEC. In this retrospective study, we collected data from the 18 Surveillance, Epidemiology, and End Results (SEER) registries cohort between 2004 and 2019, as well as from a Chinese institutional registry covering the period from 2012 to 2022. We assessed the annual percentage change (APC) in incidence of SCEC. Kaplan-Meier and Cox regression analyses were conducted to evaluate survival outcomes. Additionally, nomograms were developed for overall survival (OS) and cancer-specific survival (CSS) in the SEER cohort for SCEC and validated in an independent Chinese cohort. This analysis included 299 SCEC patients from the SEER cohort and 66 cases from the Chinese cohort. During the period of 2004-2019, the incidence of SCEC reached a plateau, with an APC of -1.40 (95% confidence interval [CI]: -4.3 to 1.40, P > 0.05). Multivariable Cox regression analysis revealed that age, distant metastasis, and chemotherapy were independent factors for OS, while distant metastasis and chemotherapy were independent factors for CSS. The nomograms developed for OS and CSS in SCEC exhibited remarkable accuracy and reliable predictive capacity in estimating 1-year, 3-year, and 5-year OS and CSS. SCEC is a rare malignancy with aggressive behavior. Distant metastasis is significantly associated with worse OS and CSS in patients with SCEC. Currently, chemotherapy remains the primary treatment approach for SCEC.

Circulating Chromogranin A Is Associated With Disease Extent, Progression, and Recurrence in Patients With Nonfunctioning Pancreatic Neuroendocrine Tumor

OBJECTIVES

Nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) are rare tumors with heterogeneous biology. Radiology and serum biomarkers are used for postresection surveillance; however, no universally established protocol exists. Serum chromogranin A (CgA) concentration is elevated in NF-PNET and generally correlates with burden of disease; many CgA studies include mixed gastrointestinal and pancreatic populations. We sought to review the NF-PNET literature with focus on postresection surveillance and hypothesized that CgA is useful for surveillance after NF-PNET resection.

MATERIALS AND METHODS

Comprehensive English literature review by PICO criteria (P, human NF-PNET patients; I, pancreatectomy; C, none; O, CgA correlation with disease recurrence).

RESULTS

Four studies yielded granular data for resected NF-PNET patients. From 333 patients, 113 recurred and 110 (97%) had elevated CgA. Additional 7 studies with mixed gastro-entero-pancreatic NET included 269 NF-PNET patients. In these patients, CgA uniformly predicted disease extent.

CONCLUSIONS

Serum CgA correlates with disease extent in NF-PNET and is useful for surveillance after resection of NF-PNET.

Primary neuroendocrine carcinoma of the fallopian tube with exceeding 10 years follow-up: Case report and review of the literature

Neuroendocrine carcinomas typically originate from the digestive system and lungs; however, their occurrence in the female genital tract, particularly in the fallopian tube, is exceedingly rare. Currently, there is no established treatment guideline for neuroendocrine neoplasms of the fallopian tube. In this report, we presented a case of small cell neuroendocrine carcinoma of the fallopian tube, with a survival period exceeding 10 years-which is the longest recorded survival among reported cases of fallopian tube neuroendocrine tumors. The patient underwent a standard open radical tumor resection and lymphadenectomy, followed by adjuvant chemotherapy with cisplatin and etoposide, offering valuable evidence for potential standardized treatment approaches in such rare case.

Development and validation of predictive models for distant metastasis and prognosis of gastroenteropancreatic neuroendocrine neoplasms

Imaging examinations exhibit a certain rate of missed detection for distant metastases of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). This study aims to develop and validate a risk prediction model for the distant metastases and prognosis of GEP-NENs. This study included patients diagnosed with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015. External validation was performed with patients from the China-Japan Union Hospital of Jilin University. Univariate and multivariate logistic regression analyses were conducted on the selected data to identify independent risk factors for distant metastasis in GEP-NENs. A nomogram was subsequently developed using these variables to estimate the probability of distant metastasis in patients with GEP-NENs. Subsequently, patients with distant metastasis from GEP-NENs were selected for univariate and multivariate Cox regression analyses to identify prognostic risk factors. A nomogram was subsequently developed to predict overall survival (OS) in patients with GEP-NENs. Finally, the developed nomogram was validated using Receiver Operating Characteristic (ROC) curves, calibration curves, and Decision Curve Analysis (DCA). Kaplan-Meier analysis was employed to evaluate survival differences between high-risk and low-risk groups. A total of 11,207 patients with GEP-NENs were selected from the SEER database, and 152 patients from the China-Japan Union Hospital of Jilin University were utilized as an independent external validation cohort. Univariate and multivariate logistic regression analyses revealed that the primary tumor site, tumor grade, pathological type, tumor size, T stage, and N stage are independent predictors of distant metastasis in GEP-NENs. Additionally, among the 1732 patients with distant metastasis of GEP-NENs, univariate and multivariate Cox regression analyses identified N stage, tumor size, pathological type, primary site surgery, and tumor grade as independent prognostic factors. Based on the results of the regression analyses, a nomogram model was developed. Both internal and external validation results demonstrated that the nomogram models exhibited high predictive accuracy and significant clinical utility. In summary, we developed an effective predictive model to assess distant metastasis and prognosis in GEP-NENs. This model assists clinicians in evaluating the risk of distant metastasis and in assessing patient prognosis.

Endoscopic resection of rectal neuroendocrine tumors: zero disease-related deaths during a 10-year follow-up period

BACKGROUND

Gastrointestinal neuroendocrine tumors (GI-NETs) are slow-growing tumors with the potential for malignancy that originate from neuroendocrine cells. Therefore, early diagnosis and treatment of GI-NETs are necessary to prevent metastasis. The widespread use of colonoscopy, which allows early detection of rectal neuroendocrine tumors (rNETs) that are small enough to be treated endoscopically, has resulted in an increasing rate of endoscopic resection of rNETs. However, whether the long-term prognosis of endoscopically resected rNETs is favorable has not yet been determined. This study aimed to assess whether endoscopically resected rNETs affect the long-term prognosis of patients.

METHODS

We retrospectively reviewed the medical records of 163 consecutive patients with rNETs who underwent endoscopic resection at 11 hospitals in Japan between 1999 and 2012. The primary analysis focused on 47 patients with 51 rNETs who underwent ≥ 10 years of follow-up. The secondary analysis focused on patients who underwent less than 10 years of follow-up.

RESULTS

The median follow-up period of patients included in the primary analysis was 12.3 years (range, 10-19.1 years). The median lesion size was 5 mm (range, 2-12). Three lesions were treated using conventional endoscopic mucosal resection (EMR). Twenty-nine lesions were treated using modified EMR. Nineteen lesions were treated using endoscopic submucosal dissection. The R1 resection rate and lymphovascular invasion rate were 15.7% and 25.5%, respectively. The curative resection (CR) rate and non-CR rate were 66.7% and 33.3%, respectively. Two patients with lesions treated with non-CR underwent radical surgery. None of the 47 patients experienced lesion recurrence during the 10-year follow-up period. Two patients whose lesions were treated with CR died of other diseases.

CONCLUSIONS

Death attributable to rNETs did not occur among patients who underwent at least 10 years of follow-up after endoscopic resection.

Hepatic Recurrence of Neuroendocrine Tumor Component in Gallbladder Cancer

ABSTRACT

A 60-year-old man underwent an extended cholecystectomy with regional lymphadenectomy for T2N0M0 gallbladder cancer (GBC), which showed significant FDG uptake (SUV max = 6.5). However, CT scan at 24 months postsurgery revealed multiple hepatic masses. Unlike the primary GBC, the hepatic masses showed limited FDG uptake (SUV max = 3.7). A tumor biopsy revealed the diagnosis of a grade 3 neuroendocrine tumor. Furthermore, the hepatic masses showed significant uptake on somatostatin receptor scintigraphy. Upon reevaluation, the primary resected specimen was found to include approximately 10% of neuroendocrine tumor components. This case suggests that different FDG uptake between primary and metastatic cancer may necessitate differential diagnosis.

Everolimus in the Treatment of Neuroendocrine Tumors: Lights and Shadows

Neuroendocrine tumors (NETs) comprise a heterogeneous group of neoplasms that originate from neuroendocrine cells, characterized by their ability to secrete hormones and peptides. Once considered rare, the incidence of NETs has steadily increased due to improved diagnostic modalities. The therapeutic landscape is multifaceted, ranging from surgery for localized disease to pharmacological interventions for advanced cases. However, the absence of robust predictive biomarkers precludes patient stratification and optimization of therapy. Everolimus, an oral mTOR inhibitor, has emerged as a key therapeutic agent due to its dual role in inhibiting cell proliferation and angiogenesis. Nevertheless, challenges such as resistance mechanisms, toxicity and optimal treatment sequencing remain unresolved. This article provides a comprehensive review of the role of everolimus in the management of NETs, focusing in particular on unresolved issues, from the absence of predictive biomarkers to the unavailability of defined guidelines for determining the correct therapeutic sequence.

Usefulness of Semiautomated 3D Volumetric Assessment of Liver Tumor Burden for Patients With Unresectable Pancreatic Neuroendocrine Tumor: A Pilot Study

OBJECTIVES

In patients with metastatic pancreatic neuroendocrine tumors (PanNETs), the Ki-67 index is objectively assessed by pathologists; however, liver tumor burden (LTB) depends on the subjective judgment of physicians. This study aimed to elucidate the usefulness of the semi-automated 3D volumetric assessment of LTB in patients with PanNET.

MATERIALS AND METHODS

We retrospectively reviewed 29 patients (40 computed tomographies [CTs]) with metastatic PanNETs. LTB was measured using a semiautomated 3D volumetric software program (volumetric assessment) or evaluated independently by 6 clinicians using CT imaging (visual assessment). The treatment map was classified into 3 groups based on LTB and Ki-67 index.

RESULTS

Visual and volumetric assessments of the LTB were well correlated. The LTB was significantly higher on visual assessment than volumetric assessment (P < 0.01). Categorization on the map was consistent between the visual and volumetric evaluations in 23 patients (equal group). The remaining 6 patients were overestimated by visual assessment (overestimated group). Progression-free survival was significantly longer in patients in the 'equal group' than the 'overestimated group' (981 vs 366 days, P < 0.01).

CONCLUSIONS

This pilot study revealed a good correlation between visual and volumetric assessments, and visual assessment overestimated LTB, compared to volumetric assessment.

Risk factors for and prognostic impact of lateral pelvic lymph node metastasis in patients with rectal neuroendocrine tumors: a single-center retrospective analysis of 214 cases with radical resection

PURPOSE

Lateral pelvic lymph node (LPLN) metastasis of rectal neuroendocrine tumors (NETs) is rare, with unknown oncological features. We investigated the oncological impact of LPLN metastasis in patients with rectal NETs.

METHODS

This study included 214 patients with rectal NETs who underwent curative surgery. We evaluated their clinicopathological characteristics and short- and long-term outcomes.

RESULTS

LPLN dissection was performed in 15 patients with LPLN swelling ≥ 7 mm (preoperative imaging); 12 patients had LPLN metastases, 6 of whom had LPLN metastases without mesorectal lymph node metastases (skip metastasis). The short-term outcomes were similar between the groups with and without LPLN dissection. The median follow-up period was 59.4 months, and patients with LPLN metastasis showed significantly shorter disease-free and overall survival rates than those without metastasis. Among 199 patients who did not undergo LPLN dissection, only 1 had LPLN recurrence. In a univariate analysis, tumor depth, tumor grade, and LPLN metastasis were associated with the overall survival. In the multivariate analysis, only LPLN metastasis was an independent predictor of the overall survival.

CONCLUSIONS

LPLN metastasis is a poor prognostic factor for patients with rectal NETs. LPLN enlargement can be considered an indication for dissection, owing to its high rate of metastasis and associated poor prognosis.

Risk factors for lateral pelvic lymph node metastasis in patients with rectal neuroendocrine tumors: a systematic review and meta-analysis

Background and objective

Lateral pelvic lymph node (LPLN) metastasis is one of the prominent reasons for local recurrence in patients with rectal neuroendocrine tumors (RNETs). The evaluation criteria of lateral lymph node metastasis for patients and the indications and value of lateral pelvic lymph node dissection (LPLD) have been controversial. Total mesorectal excision (TME), a conventional surgical treatment for RNETs, excluding lateral lymph nodes, may be one of the reasons for postoperative local recurrence. This study aimed to analyze the risk factors for LPLN metastasis in patients with RNETs in order to guide surgical methods.

Methods

We searched relevant databases (PubMed, Embase, Medline, Cochrane Library, and Web of Science) for articles published between 1 January 2000 and 1 April 2024 to evaluate the risk factors for LPLN metastasis in patients with RNETs in this meta-analysis.

Results

A total of seven articles with 433 patients were included in this study. The overall results showed that a WHO grade > G1, tumor invasion of the muscularis propria or deeper, lymphovascular invasion (LVI), mesorectal lymph node metastasis (MLNM), and distant metastasis (M1) were significant risk factors for LPLN metastasis in patients with RNETs (P <0.05).

Conclusion

This study identified key risk factors for LPLN metastasis in patients with RNETs, providing guidance for treatment strategies. A comprehensive evaluation of these risk factors and imaging findings is recommended to tailor personalized treatment strategies that optimize survival outcomes and improve quality of life.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024581891.

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.

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.

Predictors Based on the Radiologic Characteristics for Aggressiveness of Small (< 20 mm) Nonfunctioning Pancreatic Neuroendocrine Tumors

BACKGROUND AND OBJECTIVES

To find the association between preoperative computed tomography (CT) features combined with tumor marker and known high-risk factors of small nonfunctioning pancreatic neuroendocrine tumors (NF-PNETS), thereby selecting appropriate treatment strategy for these patients.

METHOD

One hundred fourteen patients with NF-PNETs< 20 mm who underwent surgical operation were retrospectively analyzed from 2009 to 2023. Univariate and multivariable logistic regression analyses were performed to find the relationship between preoperative clinical psychological and CT features and high-risk factors. The overall survival (OS) rates with and without high-risk factors were compared.

RESULTS

Of 114 patients, 29(25%) had at least one of these high-risk factors. Main pancreatic duct dilation (OR, 3.315; 95% CI, 1.079-10.184; p = 0.036), irregular tumor margin (OR, 2.955; 95% CI, 1.021-8.551; p = 0.046), positive tumor marker (OR, 6.047; 95% CI, 1.408-25.963; p = 0.015) were associated with increased odds of having any of these high-risk factors. The time to death differed significantly between patients with and without high-risk factors. Patients combining with high-risk factors were associated with lower 3- and 5-year OS (100% vs. 81.8%, 93.1% vs. 81.8%, respectively; p = 0.035 for both).

CONCLUSION

Main pancreatic duct dilation, irregular tumor margin and positive tumor marker could screen a subset of patients recommended for surgery.

Initial Application of Fluorescence Imaging for Intraoperative Localization of Small Neuroendocrine Tumors in the Pancreas: Case Report and Review of the Literature

BACKGROUND

Indocyanine green is commonly used for laparoscopic hepatectomy but remains uncommon in pancreatic surgery. Given the increasing number of small neuroendocrine tumors found in the pancreas and the heavy reliance on laparoscopic ultrasound for intraoperative localization, we attempted to use indocyanine green for these tumors. Our results show good localization and have the potential to provide a valuable clinical aid.

CASE PRESENTATION

This case report details five patients with preoperative diagnosis of pancreatic neuroendocrine tumors of small endocrine tumors, intraoperative successful localization, and successful completion of laparoscopic partial resection of pancreatic tumors by indocyanine green fluorescence staining; none of the patients experienced serious complications after surgery and were discharged from the hospital, and routine pathology confirmed that four cases were pancreatic neuroendocrine tumors of G1 stage, and one case was pancreatic neuroendocrine cell hyperplasia.

CONCLUSION

Fluorescence imaging technology safely aids in the intraoperative localization of small pancreatic neuroendocrine tumors.

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.

Clinical significance of positive resection margin for patients with rectal neuroendocrine tumors within 20 mm following initial endoscopic resection: A multi-center study

BACKGROUND

The incidence of rectal neuroendocrine tumors (RNETs) has witnessed a significant surge, with a notable proportion being amenable to endoscopic removal. However, the clinical significance of positive resection margin for RNETs patients following endoscopic resection remain unknown, resulting in a lack of consensus regarding the appropriateness of implementing salvage treatment.

METHODS

In this large, multicenter, retrospective cohort study, we analyzed the medical records of individuals who underwent endoscopic resection for RNETs and classified them into two groups: the positive resection margin and the negative resection margin group. The overall survival (OS) and disease-free survival (DFS) were compared among two group. The independent variables were identified using univariate and multivariate logistic regression analyses to predict positive resection margin. Then, the model was established to predict the patients with positive resection margin using multivariate logistic regression.

RESULTS

181 RNETs patients (34.3 %) represented positive margin after endoscopic resection. Following a median follow-up period of 72 months, tumor recurrence manifested in 12 out of 527 patients (2.2 %) and the presence of positive resection margin was associated with worse DFS. Independent factors correlating with positive resection margin included endoscopic resection method choice, RNETs located in the low rectum, NLR >4.44 and tumor size exceeding 14.89 mm. A prediction model was therefore established with high predictive accuracy and excellent clinical applicability determined by calibration curves and DCA curve. Among RNETs patients with positive margin following endoscopic resection, implementing salvage treatment was beneficial for improving DFS and salvage endoscopic resection offer equal efficiency compared with salvage radical resection.

CONCLUSIONS

Positive resection margin following endoscopic resection may indicate negative prognosis. Salvage treatment can improve the prognosis of RNETs patients with positive resection margin. Notably, salvage local resection exhibited similar efficacy compared with radical surgery in term of survival benefit.

Development and validation of a prognostic nomogram for elderly-onset pancreatic neuroendocrine carcinoma: a prospective cohort study from the SEER database

Background

The incidence of elderly-onset pancreatic neuroendocrine carcinoma (PanNEC) is increasing. This study investigated independent risk factors affecting cancer-specific survival (CSS) and constructed a nomogram to predict CSS in patients with elderly-onset PanNEC.

Methods

PanNEC patients older than 50 years from the Surveillance, Epidemiology, and End Results database were retrospectively selected from 2010 to 2021 and were randomly divided into a training set and a validation set. Independent factors affecting CSS were selected by univariate and multivariate analyses. The nomogram was built using significant variables. The discrimination and calibration of the nomogram were evaluated by the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis.

Results

A total of 407 patients were selected and randomly assigned to a training set or a validation set at a 6:4 ratio. In the selected population, 227 individuals (55.8%) were male, 313 (76.9%) were white, with a mean age of 69.4 years. Among them, 318 individuals (78.1%) died due to the tumor, with a CSS time of 6 months. Multivariate Cox analysis showed that age [hazard ratio (HR): 1.56, 95% confidence interval (CI): 1.10-2.22, P=0.01], surgery (HR: 2.32, 95% CI: 1.27-4.23, P=0.006), chemotherapy (HR: 2.39, 95% CI: 1.68-3.38, P<0.001), tumor, nodes, and metastasis (TNM) stage (HR: 3.96, 95% CI: 1.19-13.19, P=0.03), and liver metastasis (HR: 1.75, 95% CI: 1.16-2.65, P=0.008) were independent risk factors that shortened CSS. The AUCs of the nomogram for the 6-month, 1-year, and 2-year CSS were 0.826, 0.791, and 0.8 in the training set and 0.848, 0.775, and 0.781 in the validation set, respectively. Calibration curves showed that the nomogram could accurately predict the 6-month, 1-year, and 2-year CSS in both datasets. Furthermore, decision curve analysis indicated that the nomogram had clinical benefits.

Conclusions

The nomogram for CSS in patients with elderly-onset PanNEC showed good predictive power, enabling clinicians to understand patient's prognosis and make appropriate decisions.

Treatment indicators and prognostic factors in colorectal neuroendocrine neoplasms and adenocarcinoma with neuroendocrine differentiation: a single center retrospective study

PURPOSE

This study compared survival and metastasis occurrence between colorectal neuroendocrine neoplasms (cNEN) and colorectal adenocarcinoma with neuroendocrine differentiation (cNED) and further explored their prognostic factors and treatment indicators.

METHODS

Patients diagnosed as cNEN and cNED in West China Hospital from January 2009 to December 2020 were enrolled. The diagnosis and metastasis rates were calculated. Univariate and multivariate Cox analyses were conducted for progression-free survival (PFS) in cNEN surgical patients, and generalized linear regression was used for metastatic disease.

RESULT

The study enrolled 435 patients, including 257 neuroendocrine tumors (NET), 52 neuroendocrine carcinomas (NEC), 29 mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN), and 97 NED patients, of whom 202 received local resection, and 233 received radical resection. Metastasis rates were higher in MiNEN and NEC groups compared to other groups (NED: 28.9%, MiNEN: 58.6%, NEC: 65.4%, NET: 8.6%, p < 0.001). The liver is the main metastatic site in cNEN, whereas cNED metastasized to various sites. For NEC and MiNEN patients, colon location (p = 0.002) and T stage > 2 (p = 0.040) were associated with disease progression separately. Independent risk factors for metastatic NET included tumor grade G2/G3 (p < 0.001), colon location (p = 0.001), size ≥ 1 cm (p = 0.005), and CK20 partial positive (p < 0.001).

CONCLUSION

cNEN show high metastatic capacity and are challenging to diagnose. More aggressive treatment and follow-up strategies are necessary for those patients. NET tumor grade higher than G2, size larger than 1 cm, or located in the colon should be managed with radical surgery.

The prognostic and therapeutic value of the tumor microenvironment and immune checkpoints in pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (Pan-NEN) represent a group of highly heterogeneous cancers, characterized by complex and diverse biological behavior. The objective of this study was to systematically investigate the immunological features of the tumor microenvironment (TME) in Pan-NEN, aiming to identify prognostic biomarkers and explore the therapeutic potential of immunotherapy for Pan-NEN. Tumor and adjacent normal tissues were collected from 56 patients with Pan-NEN. Immunohistochemical analysis was conducted on tumor tissues using a panel of monoclonal antibodies targeting key immune markers. The expression levels of these markers were quantitatively assessed and correlated with clinicopathological features and overall survival. Low expression of CD3, CD8, CD4, CD68, CD163, Foxp3, CD56, CD69, GZMB, HLA-1, HLA-II, PD-1, and PD-L1 were observed in the majority of Pan-NEN patient samples. PD-1 expression was positively correlated with CD4 and Foxp3 expression, while PD-L1 expression was positively correlated with CD68, CD163, and Foxp3 expression; HLA-II expression was positively correlated with GZMB expression. Infiltration of lymphocytes (CD3 + or CD8+) and macrophages (CD68 + or CD163+) and expression of PD-1/PD-L1 were more pronounced in poorly differentiated neuroendocrine carcinoma (Pan-NEC) compared to well-differentiated neuroendocrine tumors (Pan-NET), while CD68 and PD-L1 correlated with advanced disease stage. Conversely, HLA-I antigen expression was commonly downregulated in Pan-NEC. Univariate Cox proportional hazard analysis demonstrated that tumor grade, stage; CD4+, CD68+, and CD163 + cell count; and expression of PD-1 and PD-L1 were significantly associated with poor survival outcomes, while the positive expression of HLA-I was correlated with a more favorable survival prognosis. Furthermore, multivariate Cox proportional hazard analyses revealed that tumor grade, stage, and PD-1 expression are independent prognostic factors. The immunological landscape of Pan-NEN offers potential prognostic value and therapeutic targets. The findings suggest that immunotherapy, particularly targeting the PD-1/PD-L1 pathway, may serve as a promising strategy for the treatment of Pan-NEN, especially for Pan-NEC patients.

Central pancreatectomy of the remnant pancreas without reconstruction after pancreatoduodenectomy

BACKGROUND

There are several reports on the safety and feasibility of pancreatoduodenectomy (PD) without reconstruction of the small remnant pancreas. However, a few studies have explored central pancreatectomy (CP) for non-reconstructed small remnant pancreases after PD. This study presents a case of CP without pancreatic reconstruction after PD.

CASE PRESENTATION

A 58-year-old man with cerebral palsy underwent PD for distal cholangiocarcinoma. Three years postoperatively, a 12-mm tumor was detected in the remnant pancreatic body and diagnosed as a pancreatic neuroendocrine neoplasm. Surgical resection was performed, because the tumor was enlarged and chemotherapy resistant. The afferent loop with pancreatojejunostomy anastomosis was dissected, and CP, including pancreatojejunostomy anastomosis, was performed. Given the remnant pancreas was hard and atrophic, the pancreatic tail was transected using a stapler without reconstructing the small remnant pancreas. The patient experienced no postoperative complications including postoperative pancreatic fistula, and the endocrine function of the pancreas was preserved.

CONCLUSIONS

We present a case of remnant pancreatic CP that did not require reconstruction after PD. Preservation of the small remnant pancreas without reconstruction during CP may be feasible to maintain endocrine function in select patients after PD.

Comparative analysis of international guidelines on the management of advanced non-functioning well-differentiated pancreatic neuroendocrine tumors

This review presents a comprehensive comparative analysis of international guidelines for managing advanced, non-functioning, well-differentiated pancreatic neuroendocrine tumors (panNETs). PanNETs, which represent a significant proportion of pancreatic neuroendocrine neoplasms, exhibit diverse clinical behaviors and prognoses based on differentiation, grading, and other molecular markers. The varying therapeutic strategies proposed by different guidelines reflect their distinct emphases and regional considerations, such as the ESMO guideline's focus on advanced disease management and the ENETS guidance paper's multidisciplinary approach. This review examines the most recent guidelines from ESMO, NCCN, ASCO, ENETS, and NANETS, analyzing the recommendations for first-line therapies and subsequent treatment pathways in different clinical scenarios. Significant variations are observed in the recommendations, particularly concerning the choice and sequence of systemic therapies, the role of tumor grading and the Ki-67 index in therapeutic decisions, and the integration of regional regulatory and clinical practices. The analysis highlights the need for a tailored approach to managing advanced NF panNETs, advocating for flexibility in applying guidelines to account for individual patient circumstances and the evolving evidence base. This work underscores the complexities of managing this patient population and the critical role of a multidisciplinary team in optimizing treatment outcomes.

Multicenter validation study of a treatment selection MAP for pancreatic neuroendocrine tumors

BACKGROUND

Somatostatin analogs, molecular-targeted agents and cytotoxic anticancer agents are available as therapeutic agents for the systemic treatment of pancreatic neuroendocrine tumors, and we have developed a first-line treatment selection MAP to enable selection of the optimal treatment strategy for pancreatic neuroendocrine tumors. The purpose of this study was to validate the usefulness of the treatment selection MAP.

METHODS

Patients who had received systemic therapy for a pancreatic neuroendocrine tumor between January 2017 and December 2020 were compared according to whether they had been treated as recommended by the MAP (matched patients) or not (unmatched patients) to determine whether better outcomes were achieved by the matched patients. The primary endpoint was progression-free survival of the matched group and unmatched groups in the somatostatin analog, molecular-targeted agent and cytotoxic anticancer agents areas of the MAP.

RESULTS

There were 41 (55%) MAP-matched patients in all areas among the 74 patients registered at seven hospitals. The MAP-matched rates were 100, 77 and 38% in the somatostatin analog area, molecular-targeted agent area and cytotoxic anticancer agents area, respectively. All of the unmatched patients had been selected for less intensive treatment. The median progression-free survival in the matched group and unmatched group in the molecular-targeted agent area of the MAP were 46.6 and 15.4 months, respectively, and a multivariate analysis identified MAP-matched (hazard ratio 0.18 [95% confidence interval: 0.04-0.87], P = 0.032) as the only significant independent favorable predictive factor.

CONCLUSION

The usefulness of the MAP for treatment selection was validated in the molecular-targeted agent area of the MAP.

Endoscopic and Surgical Treatment of Gastrointestinal Neuroendocrine Neoplasms: A Population-based Comparative Study

BACKGROUND

Controversy surrounds the indications for endoscopic treatment (ET) versus surgery in addressing gastrointestinal neuroendocrine neoplasms (GI-NENs). This paper aims to compare the long-term survival prognosis between ET and surgery for patients with GI-NENs.

METHODS

A retrospective analysis of GI-NEN patients diagnosed between 2000 and 2020 was conducted using the SEER database. Overall survival (OS) and cancer-specific survival (CSS) were estimated using the Kaplan-Meier method. Prognostic factors were assessed through univariate and multivariate Cox regression analyses. Propensity score matching (PSM) was employed to adjust for clinical variables.

RESULTS

This study encompassed 12,016 patients with GI-NENs, with 3732 patients (31.1%) undergoing ET and 8284 patients (68.9%) opting for surgery. The rectum was the most frequent location for ET, while the small bowel was the predominant site for surgery. Both the ET and surgical groups exhibited similar overall survival risk and cancer-specific survival risk before and after matching. No significant differences in the 1-year, 3-year, 5-year, and 10-year OS and CSS rates were observed between the ET and surgery groups after PSM. Nevertheless, subgroup analysis revealed a significantly better CSS in the ET group than the surgery group, particularly in stage I and tumors sized <10mm ( P <0.01). In the colon subgroup, the OS and CSS of the ET group were superior to those of the surgery group ( P <0.05).

CONCLUSION

Endoscopic treatment and surgery demonstrate comparable long-term survival prognoses for treating GI-NENs. ET emerges as a viable option for patients averse to surgical interventions.

Mixed neuroendocrine-non-neuroendocrine neoplasm of the bile duct with long-term prognosis after neoadjuvant chemotherapy

A 74-year-old man with obstructive jaundice presented with a thickened distal bile duct wall. A transpapillary forceps biopsy revealed an adenocarcinoma; however, because the tumor image was different from that of a typical cholangiocarcinoma, endoscopic ultrasound-guided fine-needle aspiration was performed on the tumor and enlarged lymph nodes. The tumor cells were positive for synaptophysin and CD56 with a Ki67 labeling index of 95%, and he was diagnosed with small cell neuroendocrine carcinoma. We diagnosed a bile duct tumor with neuroendocrine carcinoma component with lymph node metastasis. Preoperative chemotherapy for neuroendocrine carcinoma was administered because R0 resection was difficult and the risk of postoperative recurrence was high. Three courses of chemotherapy with carboplatin and etoposide resulted in marked tumor shrinkage, and radical resection was performed 3 months after diagnosis. Postoperative pathology revealed adenocarcinoma in the mucosal epithelium and small cell neuroendocrine carcinoma in the submucosa, most of which resolved with chemotherapy. Carboplatin and etoposide were resumed as adjuvant chemotherapy, and 67 months of recurrence-free survival were achieved after surgery.

Short-term outcomes of endoscopic resection for colorectal neuroendocrine tumors: Japanese multicenter prospective C-NET STUDY

OBJECTIVES

The incidence of colorectal neuroendocrine tumors (NETs) has increased with colorectal cancer screening programs and increased colonoscopies. The management of colorectal NETs has recently shifted from radical surgery to endoscopic resection. We aimed to evaluate the short-term outcomes of various methods of endoscopic resection for colorectal NETs.

METHODS

Among those registered in the C-NET STUDY, patients with colorectal NETs who underwent endoscopic treatment as the initial therapy were included. Short-term outcomes, such as the en bloc resection rate and R0 resection (en bloc resection with tumor-free margin) rate, were analyzed based on treatment modalities.

RESULTS

A total of 472 patients with 477 colorectal NETs received endoscopic treatment. Of these, 418 patients with 421 lesions who met the eligibility criteria were included in the analysis. The median age of the patients was 55 years, and 56.9% of them were men. The lower rectum was the most commonly affected site (88.6%), and lesions <10 mm accounted for 87% of the cases. Endoscopic submucosal resection with a ligation device (ESMR-L, 56.5%) was the most common method, followed by endoscopic submucosal dissection (ESD, 31.4%) and endoscopic mucosal resection using a cap (EMR-C, 8.5%). R0 resection rates <10 mm were 95.5%, 94.8%, and 94.3% for ESMR-L, ESD, and EMR-C, respectively. All 16 (3.8%) patients who developed treatment-related complications could be treated conservatively. Overall, 23 (5.5%) patients had incomplete resection without independent clinicopathological risk factors.

CONCLUSION

ESMR-L, ESD, and EMR-C were equally effective and safe for colorectal NETs with a diameter <10 mm.

Defining the optimal segmentation method for measuring somatostatin receptor expressing tumor volume on 68 Ga-DOTATATE positron emission tomography/computed tomography to predict prognosis in patients with gastroenteropancreatic neuroendocrine tumors

OBJECTIVE

We aimed to compare different segmentation methods used to calculate prognostically valuable volumetric parameters, somatostatin receptor expressing tumor volume (SRETV), and total lesion somatostatin receptor expression (TLSRE), measured by 68 Ga-DOTATATE PET/CT and to find the optimal segmentation method to predict prognosis.

PATIENTS AND METHODS

Images of 34 patients diagnosed with gastroenteropancreatic neuroendocrine tumor (GEPNET) who underwent 68 Ga-DOTATATE PET/CT imaging were reanalyzed. Four different threshold-based methods (fixed relative threshold method, normal liver background threshold method, fixed absolute standardized uptake value (SUV) threshold method, and adaptive threshold method) were used to calculate SRETV and TLSRE values. SRETV of all lesions of a patient was summarized as whole body SRETV (WB-SRETV) and TLSRE of all lesions of a patient was computed as whole body TLSRE (WB-TLSRE).

RESULTS

WB-SRETVs calculated with all segmentation methods were statistically significantly associated with progression-free survival except WB-SRETV at which was calculated using adaptive threshold method. The fixed relative threshold methods calculated by using 45% (WB-SRETV 45% ) and 60% (WB-SRETV 60% ) of the SUV value as threshold respectively, were found to have statistically significant highest prognostic value (C-index = 0.704, CI = 0.622-0.786, P  = 0.007). Among WB-TLSRE parameters, WB-TLSRE 35% , WB-TLSRE 40% , and WB-TLSRE 50% had the highest prognostic value (C-index = 0.689, CI = 0.604-0.774, P  = 0.008).

CONCLUSION

The fixed relative threshold method was found to be the most effective and easily applicable method to measure SRETV on pretreatment 68 Ga-DOTATATE PET/CT to predict prognosis in GEPNET patients. WB-SRETV 45% (cutoff value of 11.8 cm 3 ) and WB-SRETV 60% (cutoff value of 6.3 cm 3 ) were found to be the strongest predictors of prognosis in GEPNET patients.

Multiple Gastric Neuroendocrine Tumors Associated with Long-term Use of a Proton Pump Inhibitor and a Potassium-competitive Acid Blocker

A 52-year-old man who had been using a proton pump inhibitor (PPI) and a potassium-competitive acid blocker (P-CAB) for 14 years underwent esophagogastroduodenoscopy and was found to have three neuroendocrine tumors (NETs) in the gastric body. Following detailed examinations, parietal cell dysfunction was excluded, and the NETs did not meet the criteria for the Rindi classification types I-III. The lesions were ultimately considered to be associated with the long-term use of the PPI and P-CAB. We performed endoscopic submucosal dissection of the lesions, with no recurrence or new lesions noted after discontinuation of the PPI and P-CAB.

Factors Affecting Nonfunctioning Small Pancreatic Neuroendocrine Neoplasms and Proposed New Treatment Strategies

BACKGROUND & AIMS

Despite previously reported treatment strategies for nonfunctioning small (≤20 mm) pancreatic neuroendocrine neoplasms (pNENs), uncertainties persist. We aimed to evaluate the surgically resected cases of nonfunctioning small pNENs (NF-spNENs) in a large Japanese cohort to elucidate an optimal treatment strategy for NF-spNENs.

METHODS

In this Japanese multicenter study, data were retrospectively collected from patients who underwent pancreatectomy between January 1996 and December 2019, were pathologically diagnosed with pNEN, and were treated according to the World Health Organization 2019 classification. Overall, 1490 patients met the eligibility criteria, and 1014 were included in the analysis cohort.

RESULTS

In the analysis cohort, 606 patients (59.8%) had NF-spNENs, with 82% classified as grade 1 (NET-G1) and 18% as grade 2 (NET-G2) or higher. The incidence of lymph node metastasis (N1) by grade was significantly higher in NET-G2 (G1: 3.1% vs G2: 15.0%). Independent factors contributing to N1 were NET-G2 or higher and tumor diameter ≥15 mm. The predictive ability of tumor size for N1 was high. Independent factors contributing to recurrence included multiple lesions, NET-G2 or higher, tumor diameter ≥15 mm, and N1. However, the independent factor contributing to survival was tumor grade (NET-G2 or higher). The appropriate timing for surgical resection of NET-G1 and NET-G2 or higher was when tumors were >20 and >10 mm, respectively. For neoplasms with unknown preoperative grades, tumor size >15 mm was considered appropriate.

CONCLUSIONS

NF-spNENs are heterogeneous with varying levels of malignancy. Therefore, treatment strategies based on tumor size alone can be unreliable; personalized treatment strategies that consider tumor grading are preferable.

Efficacy and safety of streptozocin-based chemotherapy for gastroenteropancreatic neuroendocrine tumors in Japanese clinical practice

BACKGROUND

Streptozocin has been used to treat neuroendocrine tumors in Europe and the USA; however, its actual status in Japan has not been fully clarified owing to the rarity of this disease and the relatively recent approval of streptozocin in Japan.

METHODS

We retrospectively analyzed 53 patients with gastroenteropancreatic neuroendocrine tumors who were treated with streptozocin-based chemotherapy at two Japanese hospitals between January 2004 and June 2023.

RESULTS

The overall response and disease control rates were 27.7 and 74.5%, respectively, and the median progression-free survival and overall survival were 7.1 and 20.3 months, respectively. Performance status ≥1 showed a significant negative correlation with progression-free survival, and performance status ≥1 and liver tumor burden ≥25% showed a significant negative correlation with overall survival. No significant differences were observed in the treatment response between pancreatic and gastrointestinal neuroendocrine tumors. No treatment-related serious adverse events were observed; however, 87.7% of patients expressed a decrease in the estimated glomerular filtration rate, which negatively correlated with the duration of streptozocin treatment (r = 0.43, P = 0.0020). In the streptozocin re-administration group (n = 5), no differences were found in efficacy between the initial and second streptozocin treatments.

CONCLUSIONS

Although streptozocin is a safe, streptozocin-induced renal dysfunction is a dilemma in streptozocin responders. Streptozocin may benefit patients with gastroenteropancreatic neuroendocrine tumors, especially those with a good performance status; however, in some cases, planned streptozocin withdrawal or switching to other drugs should be considered.

Development and Validation of a Novel Machine Learning Model to Predict the Survival of Patients with Gastrointestinal Neuroendocrine Neoplasms

INTRODUCTION

Well-calibrated models for personalized prognostication of patients with gastrointestinal neuroendocrine neoplasms (GINENs) are limited. This study aimed to develop and validate a machine-learning model to predict the survival of patients with GINENs.

METHODS

Oblique random survival forest (ORSF) model, Cox proportional hazard risk model, Cox model with least absolute shrinkage and selection operator penalization, CoxBoost, Survival Gradient Boosting Machine, Extreme Gradient Boosting survival regression, DeepHit, DeepSurv, DNNSurv, logistic-hazard model, and PC-hazard model were compared. We further tuned hyperparameters and selected variables for the best-performing ORSF. Then, the final ORSF model was validated.

RESULTS

A total of 43,444 patients with GINENs were included. The median (interquartile range) survival time was 53 (19-102) months. The ORSF model performed best, in which age, histology, M stage, tumor size, primary tumor site, sex, tumor number, surgery, lymph nodes removed, N stage, race, and grade were ranked as important variables. However, chemotherapy and radiotherapy were not necessary for the ORSF model. The ORSF model had an overall C index of 0.86 (95% confidence interval, 0.85-0.87). The area under the receiver operation curves at 1, 3, 5, and 10 years were 0.91, 0.89, 0.87, and 0.80, respectively. The decision curve analysis showed superior clinical usefulness of the ORSF model than the American Joint Committee on Cancer Stage. A nomogram and an online tool were given.

CONCLUSION

The machine learning ORSF model could precisely predict the survival of patients with GINENs, with the ability to identify patients at high risk for death and probably guide clinical practice.

Combined visual and quantitative assessment of somatostatin receptor scintigraphy for staging and restaging of neuroendocrine tumors

PURPOSE

Somatostatin receptor scintigraphy (SRS) using 111In-DTPA-DPhe1-octreotide (pentetreotide) has become an integral part of neuroendocrine neoplasm management. The lack of precise quantification is a disadvantage of SRS. This study aimed to adapt the standardized uptake value (SUV) to SRS, establish the SUV range for physiological uptake in the liver, kidney, and spleen, and elucidate the utility of combined visual and quantitative SRS assessment for staging and restaging of neuroendocrine tumors (NETs).

MATERIALS AND METHODS

This study included 21 patients with NETs who underwent 111In-pentetreotide SRS. The SUV of physiological and pathological uptake was calculated using bone single-photon emission computed tomography (SPECT) quantitative analysis software (GI-BONE). For visual analysis, the primary and metastatic lesions were scored visually on planar and SPECT images using a five-point scale. We assessed the relationships between the SUVs of the liver, kidney, and spleen in the dual phase, and among quantitative indices, visual score, and pathological lesions classification.

RESULTS

Sixty-three NEN lesions were evaluated. The mean ± standard deviation maximum SUVs (SUVmax) were liver: 4 h, 2.6 ± 1.0; 24 h, 2.2 ± 1.0; kidney: 4 h, 8.9 ± 1.8; 24 h, 7.0 ± 2.0; and spleen; 4 h, 11.3 ± 4.5; 24 h, 11.5 ± 7.6. Higher SUVmax was significantly associated with higher visual scores on dual-phase SPECT (4 h, p < 0.001; 24 h, p < 0.001) (4 h: scores 3 and 4, p < 0.05; scores 3 and 5: p < 0.01; scores 4 and 5: p < 0.01; 24 h: scores 3 and 4, p = 0.0748; scores 3 and 5: p < 0.01; scores 4 and 5: p < 0.01).

CONCLUSION

We adapted the SUV to SRS and established the range of SUV for physiological uptake in the liver, kidney, and spleen. Combined visual and quantitative assessment is useful for imaging individual lesions in greater detail, and may serve as a new tumor marker of SRS for staging and restaging of NETs.

Salvage treatment after endoscopic submucosal dissection for a rectal neuroendocrine tumor: Premeditated peranal endoscopic myectomy

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Endoscopic management of gastric, duodenal and rectal NETs: Position paper from the Italian Association for Neuroendocrine Tumors (Itanet), Italian Society of Gastroenterology (SIGE), Italian Society of Digestive Endoscopy (SIED)

The present paper reflects the position of the Italian Association for Neuroendocrine Tumors (Itanet), the Italian Society of Gastroenterology (SIGE), and the Italian Society of Digestive Endoscopy (SIED) regarding the management of patients affected by gastric, duodenal, and rectal neuroendocrine neoplasms (NENs) amenable to endoscopic treatment. The key questions discussed in this paper are summarized in Table 1. Data were extracted from the MEDLINE database through searches; expert opinions and recommendations are provided in accordance with the available scientific evidence and the authors' expertise. Recommendations are presented alongside a level of evidence and grade of recommendation based on the GRADE system. This paper specifically focuses on subgroups of NENs considered suitable for endoscopic management according to current international guidelines: i. well-differentiated gastric neuroendocrine tumors (gNET) type 1 < 2 cm and selected cases of type 3; ii. well-differentiated duodenal, non-functioning, non-ampullary NET with size < 2 cm; and well-differentiated rectal NET with size < 2 cm.

Traction Devices May Not Affect the Vertical Margin Distance in the Endoscopic Submucosal Dissection of Rectal Neuroendocrine Tumors

Introduction The usefulness of traction devices (TDs) in endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (NETs) has not been reported. The aim of this study was to investigate the impact of using a TD on the vertical margin (VM) distance in the ESD of rectal NETs. Methods In this single-center, retrospective study, we included patients with rectal NETs who were treated with ESD during 2013-2023. They were divided into TD and non-TD groups. One pathologist remeasured the VM distance (primary outcome) and the depth of submucosal invasion (SM depth). Secondary outcomes were margins, resection time, delayed bleeding, and perforation. First, we performed propensity score matching (PSM) to assess the usefulness of TD for VM distance. Then, we used multiple regression analysis to identify factors affecting the VM distance. Results The TD and non-TD groups comprised 24 and 117 lesions, respectively. Patients in the TD group were significantly younger than those in the non-TD group (P = 0.003). In the TD and non-TD groups, the VM distance was 150 μm and 100 μm, respectively (P = 0.70). Only resection time significantly differed between groups, shorter in the TD group (P = 0.005). Twenty-two cases in each group were matched after PSM, yielding no significant differences in VM distance. The use of a TD was not an independent predictor of VM distance (P = 0.65), but age (P < 0.001) and SM depth (P = 0.003) were. Conclusion Using a TD does not seem to affect the VM distance in ESD for rectal NETs.

Underwater endoscopic papillectomy for a small neuroendocrine tumor of the ampulla of Vater

Neuroendocrine tumors (NETs) of the ampulla of Vater are rare. Therefore, there is a lack of comprehensive information regarding their pathogenesis. We herein present the case of a patient with a 5-mm ampullary NET who demonstrated the presence of lymphatic invasion after undergoing endoscopic papillectomy. A 44-year-old woman was referred to our hospital for treatment of a grade 1 NET in the ampulla of Vater. Endoscopic ultrasonography revealed a hypoechoic mass within the submucosal layer without obvious infiltration into the common bile duct or the main pancreatic duct. We performed underwater endoscopic papillectomy (UEP) to remove the tumor with a negative margin. Pathological evaluation of the resected specimen showed a grade 1 NET with a negative margin. However, pancreaticoduodenectomy was subsequently performed because of the risk of lymph node metastasis, which was expected due to the significant number of NET cells infiltrating the endothelium of the lymphatic vessels. No lymph node metastasis or recurrence was observed during the 26-month follow-up period. UEP is a useful method to achieve complete resection for diagnostic and therapeutic purposes. UEP may be a novel option for endoscopic treatment of ampullary NET.

Treatment strategy and post-treatment management of colorectal neuroendocrine tumor

Following the increase in colorectal neuroendocrine tumors (NETs), there is a consequent increase in the importance of their appropriate treatment and post-treatment management. It is widely accepted that colorectal NETs sized ≥20 mm and those with muscularis propria invasion are indicated for radical surgery, and those sized <10 mm without the invasion are indicated for local resection. No consensus has been reached regarding the treatment strategy for those sized 10-19 mm without the invasion. Endoscopic resection has become a primary option for the local resection of colorectal NETs. For rectal NETs sized <10 mm, modified endoscopic mucosal resection, such as endoscopic submucosal resection with ligation device and endoscopic mucosal resection with a cap-fitted panendoscope, seems favorable because of its ability to achieve a high R0 resection rate, safety, and convenience. Endoscopic submucosal dissection can also be helpful for these lesions; however, this procedure may be more effective for large lesions or those in the colon. Management following local resection of colorectal NETs is based on the pathological evaluation of factors associated with metastasis, including tumor size, invasion depth, tumor cell proliferative activity (NET grading), presence of lymphovascular invasion, and resection margins. There remain unclear issues in managing cases with NET grading ≥2, positive lymphovascular invasion, and positive resection margins following local resection. In particular, there is confusion regarding managing positive lymphovascular invasion because positivity has become remarkably high with the increased use of the immunohistochemical/special staining. Further evidence based on long-term clinical outcomes is required to address these issues.

Two cases of pancreatic neuroendocrine tumors with ectopic ACTH syndrome during their disease course

Pancreatic neuroendocrine tumors (PanNETs) are rare malignant tumors that occur in the pancreas. They are divided into functioning and non-functioning tumors based on the presence or absence of their specific hormonal hyper-expression symptoms. Adrenocorticotropic hormone (ACTH)-producing PanNETs are rare, functional tumors, and their clinical characteristics and outcomes have not been well reported.Here, we report the cases of two patients with PanNETs who presented with ectopic ACTH syndrome (EAS) during the course of their disease. Case 1 involved a non-functioning PanNET at the time of surgery. During treatment for recurrent liver metastases, the patient presented with EAS and tumor-associated hypercalcemia, probably due to ACTH and parathyroid hormone-related peptide (PTHrP) production from the liver tumor. Case 2 was a gastrinoma, and similar to Case 1, this patient presented with EAS during the treatment of recurrent liver metastases.It is not uncommon for patients with PanNETs to have multiple hormones and develop secondary hormone secretion during their disease course, although tumor phenotypes differ between primary and metastatic sites. In patients with functioning PanNETs, symptom control with anti-hormonal therapy is essential, in addition to anti-tumor therapy, especially for EAS, which is an endocrine emergency disease that requires prompt diagnosis and treatment.

Comparing surgical and endoscopic resection approaches for colorectal neuroendocrine tumors within the diameter range of 10-20mm: an inverse probability weighting analysis based on the SEER database

Background

Currently, the primary treatment modalities for colorectal neuroendocrine tumors (CRNET) with a diameter between 10mm and 20mm are surgical resection (SR) and endoscopic resection (ER). However, it remains unclear which surgical approach yields the greatest survival benefit for patients.

Methods

This study included data from patients diagnosed with CRNET with tumor diameters ranging from 10mm to 20mm between the years 2004 and 2019, obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were categorized into ER and SR groups based on the respective surgical approaches. Inverse probability weighting (IPTW) was employed to mitigate selection bias. Kaplan-Meier analysis and log-rank tests were utilized to estimate overall survival (OS) and cancer-specific survival (CSS). Cox regression analysis (univariate and multivariate) was performed to evaluate potential factors influencing survival.

Results

A total of 292 CRNET patients were included in this study (ER group: 108 individuals, SR group: 184 individuals). Prior to IPTW adjustment, Kaplan-Meier analysis and Cox proportional hazard regression analysis demonstrated that the OS and CSS of the SR group were inferior to those of the ER group. However, after IPTW adjustment, no statistically significant differences in prognosis were observed between the two groups. Subgroup analyses revealed that patients with muscular invasion, positive lymph nodes, or distant metastasis derived greater survival benefits from SR. Significant differences in OS and CSS between the two groups were also observed across different age groups.

Conclusion

For patients with mucosal-limited lesions and without local lymph node or distant metastasis, ER is the preferred surgical approach. However, for patients with muscular invasion or positive lymph nodes/distant metastasis, SR offers a better prognosis. The choice of surgical approach should be based on the specific clinical characteristics of patients within different subgroups.

Risk of metastasis and survival in patients undergoing different treatment strategies with T1 colonic neuroendocrine tumors

PURPOSE

The efficacy and safety of local excision (LE) for small (< 1‒2 cm) colonic neuroendocrine tumors (NETs) is controversial due to the higher metastasis risk when compared with rectal NETs. The study aimed to evaluate the metastasis risk of T1 colonic NETs and compare patients' long-term prognosis after LE or radical surgery (RS).

METHODS

The Surveillance Epidemiology and End Results database was used to identify patients with T1 colonic NETs (2004‒2015). Multivariable logistic regression was performed to assess factors associated with metastasis risk. Propensity score matching was used to balance the variables. Cancer-specific survival (CSS) and overall survival (OS) were calculated to estimate the prognosis of patients with T1N0M0 colonic NETs who underwent LE or RS.

RESULTS

Of the 610 patients with colonic NETs, 46 (7.54%) had metastasis at diagnosis. Tumor size (11-20 mm) (OR = 9.51; 95% confidence interval (CI): 4.32‒21.45; P < 0.001), right colon (OR = 15.79; 95% CI 7.20‒38.56; P < 0.001), submucosal infiltration (OR = 2.08; 95% CI 0.84‒5.57; P = 0.125) were independent risk factors associated with metastasis. Of the 515 patients with T1N0M0 colonic NETs, the overall long-term prognosis of LE was as good as that of RS groups (after matching, 5-year CSS: 97.9% vs. 94.6%, P = 0.450; 5-year OS: 92.7% vs. 85.6%, P = 0.009).

CONCLUSION

Tumor size (11‒20 mm) and site (right colon) are associated with metastasis in T1 colonic NETs. In the absence of metastasis, LE could be a viable option for 0‒10 mm T1 colonic NETs with well/moderate differentiation in the left colon in terms of long-term survival.

A Case of Acute Kidney Injury, Proteinuria, and Thrombotic Microangiopathy Associated With Sunitinib Therapy in Metastatic Pancreatic Neuroendocrine Tumor

There have been rare reports of patients developing nephrotic syndrome and thrombotic microangiopathy (TMA) with tyrosine kinase inhibitors (TKIs). We present the case of a patient with a history of metastatic pancreatic neuroendocrine tumor (pNET), treated with sunitinib, who rapidly developed TMA and acute kidney injury. The patient was successfully treated with cessation of sunitinib and administration of steroids. This case report contributes to the growing body of literature surrounding the rare side effects of TKIs and our experience with the management of these adverse events.