Risk factors for positive resection margins after endoscopic resection for gastrointestinal neuroendocrine tumors

BACKGROUND

In recent years, the incidence of gastrointestinal neuroendocrine tumors (GI-NETs) has remarkably increased due to the widespread use of screening gastrointestinal endoscopy. Currently, the most common treatments are surgery and endoscopic resection. Compared to surgery, endoscopic resection possesses a higher risk of resection margin residues for the treatment of GI-NETs.

METHODS

A total of 315 patients who underwent surgery or endoscopic resection for GI-NETs were included. We analyzed their resection modality (surgery, ESD, EMR), margin status, Preoperative marking and Prognosis.

RESULTS

Among 315 patients included, 175 cases underwent endoscopic resection and 140 cases underwent surgical treatment. A total of 43 (43/175, 24.57%) and 10 (10/140, 7.14%) patients exhibited positive resection margins after endoscopic resection and surgery, respectively. Multivariate regression analysis suggested that no preoperative marking and endoscopic treatment methods were risk factors for resection margin residues. Among the patients with positive margin residues after endoscopic resection, 5 patients underwent the radical surgical resection and 1 patient underwent additional ESD resection. The remaining 37 patients had no recurrence during a median follow-up of 36 months.

CONCLUSIONS

Compared with surgery, endoscopic therapy has a higher margin residual rate. During endoscopic resection, preoperative marking may reduce the rate of lateral margin residues, and endoscopic submucosal dissection may be preferred than endoscopic mucosal resection. Periodical follow-up may be an alternative method for patients with positive margin residues after endoscopic resection.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (⁶⁴Cu-DOTATATE or ⁶⁸Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.

State of the Art in Endoscopic Therapy for the Management of Gastroenteropancreatic Neuroendocrine Tumors

OPINION STATEMENT

Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) comprise a heterogeneous group of slow growing tumors arising from the neuroendocrine cells of the gastrointestinal (GI) tract. Although they are considered relatively rare, their incidence is rising and it is believed that the more frequent use of endoscopy and imaging studies have at least in part contributed to the increased diagnosis especially of localized neoplasms. The management of these neoplasms should be guided by a multidisciplinary NEN team following appropriate staging investigations. Localized neoplasms of the GI tract may be suitable for endoscopic therapy, while patients with pancreatic NENs, unsuitable for surgery, should be considered for endoscopic ultrasound (EUS)-guided ablation. In this review, we discuss the evidence regarding endoscopic resection of luminal NENs and EUS-guided therapy of pancreatic NENs. The efficacy, safety, and other longer-term outcomes of these techniques are summarized. In conclusion, this review of endoscopic therapies for localized NENs may be a useful guide for NEN clinicians and endoscopists who are considering these therapeutic options for the management of focal GEP NENs.

Gallbladder Neuroendocrine Tumors: Is There a Need for a Specific Approach?

Neuroendocrine tumors (NETs) of the gallbladder or the biliary tree are rare. Most of the current guidelines and protocols are derived from the experience of managing lung small cell neuroendocrine carcinoma or gastrointestinal NETs. But, the overall outcome of gallbladder NETs (GB-NETs) seems worse than similarly staged lung NETs and adenocarcinoma of the gallbladder. This may be due to its rarity and lack of literature for a focused approach toward its treatment. Hence, the need for a specifically designed approach might help improve results of treatment for these rare tumors. We share our experience of 2 patients with GB-NETs and their 5-year outcome.

Gastrointestinal neuroendocrine tumors in 2020

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological, biological, and clinical characteristics that have increased in incidence and prevalence within the last few decades. They contain chromogranin A, synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor. Ki-67 index and mitotic index correlate with cellular proliferation. Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors. Most of the gastrointestinal neuroendocrine tumors are non-functional. World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm. Gastric neuroendocrine tumors arise from enterochromaffin like cells. They are classified into 4 types. Only type I and type II are gastrin dependent. Small intestinal neuroendocrine tumor is the most common small bowel malignancy. More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve. Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs. Duodenal and jejuno-ileal neuroendocrine tumors are distinct biologically and clinically. Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver. Appendiceal neuroendocrine tumors are generally detected after appendectomy. Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis. Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000. Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy, endoscopic ultrasound, serology of biomarkers, imaging studies and functional somatostatin scans. Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.

Efficacy and safety of endoscopic submucosal dissection for gastrointestinal neuroendocrine tumors: a 10-year data analysis of Northern China

Objective: Endoscopy is the main method to treat gastrointestinal neuroendocrine tumors (GI-NETs), but the specific indications are still controversial. We aim to investigate the clinical outcomes of GI-NETs patients who experienced endoscopic submucosal dissection (ESD). Methods: We retrospectively reviewed the clinical features and prognosis of 65 GI-NETs patients who underwent ESD between 2008 and 2018. Results: A total of 65 patients diagnosed with GI-NETs pathologically, bearing 75 lesions, were found by endoscopy incidentally for other symptoms. The locations of these lesions were stomach (n = 24), duodenal bulb (n = 4) and rectum (n = 47). The diameter of 75 tumors were as follows: size ≤ 1 cm (78.7%), 1 cm < size ≤ 2 cm (17.3%), 2 cm < size ≤ 3.5 cm (4.0%). Endoscopic ultrasonography (EUS) suggested that 72 lesions were confined to submucosa and 3 lesions invaded into muscularis propria. The rates of en bloc resection and complete resection were all 100% and the rates of intraoperative bleeding and perforation were 2.7% and 1.3%, respectively. None of the 65 patients had lymph nodes and distant metastasis during the period of study. Conclusion: For GI-NETs without lymph nodes and distant metastases, the lesion confined to submucosa with the diameter ≤1 cm is absolute indication of ESD. For rectal neuroendocrine tumors limited in submucosa with the diameter between 1 and 2 cm, and Type 1 gastric neuroendocrine tumors predicted to be T2, ESD should be prioritized to preserve gastrointestinal volume and function at initial treatment.

First-line systemic treatment adherence, healthcare resource utilization, and costs in patients with gastrointestinal neuroendocrine tumors (GI NETs) in the USA

AIMS

To assess treatment adherence, healthcare resource utilization, and costs in gastrointestinal neuroendocrine tumor (GI NET) patients initiating pharmacologic treatments in the US.

METHODS

In two US commercial claims databases, patients ≥18 years with ≥1 inpatient or ≥2 outpatient GI NET claims within 12 months were identified. The first claim for pharmacologic treatments (e.g. somatostatin analogs [SSAs], cytotoxic chemotherapy [CC], targeted therapy [TT]) following diagnosis, between July 1, 2009 - December 31, 2014, was defined as the index date. A 6-month pre-index NET treatment-free period, and ≥1-year post-index enrollment were required. Proportion of days covered (PDC) was calculated during the follow-up period. Outcomes were reported separately for patients with 1- and 2-years post-index enrollment. Descriptive statistics, including means, standard deviations, and frequencies and percentages for continuous and categorical data, respectively, were reported.

RESULTS

Of 1,322 patients with 1-year follow-up, 847 initiated SSA, 397 CC, 35 TT, two interferon, and 41 various combinations. Mean (SD) PDC was 0.669 (0.331) for SSA, 0.466 (0.236) for CC, and 0.505 (0.328) for TT. Mean (SD) office visits and hospitalizations, respectively, were 20.5 (13.5) and 0.59 (1.03) for SSA, 30.5 (19.8) and 0.89 (1.45) for CC, and 17.7 (12.5) and 1.23 (1.93) for TT. Total annual cost for patients during year 1 was $99,691 (82,423) for SSA, $134,912 (116,078) for CC, and $158,397 (82,878) for TT. Among 685 patients with 2-years follow-up, annual mean costs in year 2 were $8,071, $58,944, and $36,248 lower than year 1 for SSA, CC, and TT, respectively.

LIMITATIONS

Findings may not be generalizable to the US population. Claims are designed for reimbursement, not research. The study may under-estimate costs not covered by insurance.

CONCLUSION

This study reports utilization and costs associated with different treatment therapies. Costs were higher in year 1 than year 2. This two-database study offers new information on the magnitude and trends in the cost of pharmacologically-treated GI NETs.

Predictive factors associated with carcinoid syndrome in patients with gastrointestinal neuroendocrine tumors

AIM

To discover unknown factors associated with carcinoid syndrome (CS) with the goal of earlier diagnosis of CS.

METHODS

In this retrospective case-control study using United States administrative claims, patients (≥ 18 years) newly-diagnosed with gastrointestinal neuroendocrine tumors (GI NETs) without CS (controls) were exactly matched to patients with CS (cases) based on NET diagnosis date at a 3-to-1 ratio. Study index date was first CS diagnosis (controls: same distance from NET diagnosis as cases). The most observed conditions, excluding CS-associated symptoms/diagnoses, during the year before index date were assessed. Forward-stepwise logistic regression models were used to derive predictors, and were validated within another claims database.

RESULTS

In the development database, 1004 patients with GI NETs were identified; 251 (25%) had CS and 753 (75%) were controls. In the validation database, 724 patients with GI NETs were identified; 181 (25%) had CS and 543 (75%) were controls. A total of 33 common diagnoses (excluding conditions already known to be associated with CS) in the development database were entered in forward step-wise logistic regression models. In the final, validated logistic regression model, three factors prior to CS diagnosis were found consistently associated with higher risks for CS, including liver disorder [odds ratio (95%CI): 3.38 (2.07-5.51)], enlargement of lymph nodes [2.13 (1.10-4.11)], and abdominal mass [3.79 (1.87-7.69)].

CONCLUSION

GI NET patients with CS were 2-4 times as likely to have preexisting diagnoses (i.e., liver disorder, enlarged lymph nodes, abdominal mass) than non-CS patients.

Real-world treatment patterns of gastrointestinal neuroendocrine tumors: A claims database analysis

AIM

To describe real-world treatment patterns of gastrointestinal neuroendocrine tumors (GI NET).

METHODS

In this retrospective cohort study, we used 2009-2014 data from 2 United States commercial claims databases to examine newly pharmacologically treated patients using tabular and graphical techniques. Treatments included somatostatin analogues (SSA), cytotoxic chemotherapy (CC), targeted therapy (TT), interferon (IF) and combinations. We identified patients at least 18 years of age, with ≥ 1 inpatient or ≥ 2 outpatient claims for GI NET who initiated pharmacologic treatment from 7/1/09-6/30/14. A 6 mo clean period prior to first treatment ensured patients were newly treated. Patients were followed until end of enrollment or the study end date, whichever was first.

RESULTS

We identified 2258 newly treated GI NET patients: mean (SD) age was 55.6 years (SD = 9.7), 47.2% of the patients were between 55 and 64 years, and 48.8% were female. All regions of the United States were represented. 59.6% started first-line therapy with SSA monotherapy (964 with octreotide LAR, 380 with octreotide SA, and 1 with lanreotide), 33.3% CC, 3.6% TT, and 0.5% IF. The remainder received combinations. Mean follow up was 576 d. Overall mean first-line therapy duration was 361 d (449 d for SSA, 215 for CC, 267 for TT). 58.9% of patients had no pharmacological treatment beyond first line. The most common second-line was combination therapy with SSA. In graphical pattern analysis, there was no clear pattern visible after first line therapy.

CONCLUSION

In this study, 60% of patients initiated treatment with SSA alone or in combination. The relatively long time to discontinuation suggests possible sustained effectiveness and tolerability.

Systemic Therapies for Advanced Gastrointestinal Carcinoid Tumors

Well-differentiated gastrointestinal neuroendocrine tumors (GINETs) tend to be slow growing, but treatment of advanced disease remains a challenge. Somatostatin analogues (SSAs) are considered standard therapy for carcinoid syndrome. SSAs delay tumor progression in advanced well-differentiated gastroenteropancreatic NETs. Cytotoxic chemotherapy and interferon play a limited role in the treatment of nonpancreatic GINETs. There is no standard approach to treatment of patients with disease progression. Identification of systemic agents with antitumor activity in advanced disease remains an unmet medical need. Enrollment to clinical trials is encouraged; potential therapeutic targets include the vascular endothelial growth factor and mammalian target of rapamycin signaling pathways.

Nonlinear optical microscopy for label-free detection of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NETs), which are rare and slow-growing neoplasms, pose a diagnostic challenge as they are clinically silent at the time of presentation. Here, gastrointestinal neuroendocrine tumors were researched by nonlinear microscopy, and results demonstrate that this technique has the capability to identify neuroendocrine tumors in the absence of labels and can, in particular, detect rare neuroendocrine tumor cells, vascular invasion, desmoplastic reaction, and fibroelastosis induced by neuroendocrine tumors. These conclusions highlight the possibility of nonlinear optical microscopy as a diagnostic tool for label-freely differentiating neuroendocrine tumors by these histopathologic features.

High VEGF serum values are associated with locoregional spread of gastroenteropancreatic neuroendocrine tumors (GEP-NETs)

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are highly vascularized neoplasms, capable of synthethisizing VEGF-A, a key mediator of angiogenesis. In pancreatic neuroendocrine tumors (pNETs) VEGF expression is higher in benign and low-grade tumors and associated with good prognosis (neuroendocrine paradox) while the VEGF role in gastrointestinal NETs (GI-NETs) is still unclear. In this study, we examined the VEGF-1154A/G polymorphism in 145 GEP-NET patients and 150 controls. Next, we measured VEGF serum levels and VEGF tumor protein expression, comparing it with Ki67 and tumor grade. Patients' VEGF serum levels were compared with VEGF -1145A/G genotypes and metastatic status as well as with chromogranin A (CgA) and 5-hydroxyindolacetic acid (5-HIAA) in case of GI-NET patients. In this study GEP-NET patients had elevated VEGF serum values when compared to healthy controls (p = 0.0013). VEGF-1145G allele correlated with higher VEGF serum levels (p = 0.002). Patients with metastatic tumors had higher VEGF serum values when compared to patients without metastases (p = 0.033), and highest levels were observed in case of lymph node metastases (p = 0.008). VEGF-1145G allele was more frequent in non-functional GI-NET patients than in healthy controls (p = 0.041). CgA was superior to VEGF in tumor detection, while VEGF was superior to 5-HIAA. A correlation was observed between VEGF immunohistochemical staining and Ki-67 (p = 0.028). Tumours with weaker VEGF protein expression were more aggressive than tumours with stronger VEGF expression, confirming a "neuroendocrine paradox" in GI-NETs. Our results suggest the role of VEGF in GI-NETs locoregional spread.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.