Usefulness of endoscopic ultrasonography (EUS) for selecting carcinoid tumors as candidates to endoscopic resection

Endoscopic Resection for Duodenal Neuroendocrine Neoplasms between 10 and 20 mm-A Systematic Review and Meta-Analysis

Background. The optimal management of duodenal neuroendocrine neoplasms (dNENs) sized 10-20 mm remains controversial and although endoscopic resection is increasingly performed instead of surgery, the therapeutic approach in this setting is not fully standardized. We performed a systematic review of the literature and a meta-analysis to clarify the outcomes of endoscopic resection for 10-20 mm dNENs in terms of efficacy (i.e., recurrence rate) and safety. Methods. A computerized literature search was performed using relevant keywords to identify pertinent articles published until January 2023. Results. Seven retrospective studies were included in this systematic review. The overall recurrence rate was 14.6% (95%CI 5.4-27.4) in 65 patients analyzed, without significant heterogeneity. When considering studies specifically focused on endoscopic mucosal resection, the recurrence rate was 20.5% (95%CI 10.7-32.4), without significant heterogeneity. The ability to obtain the free margin after endoscopic resection ranged between 36% and 100%. No complications were observed in the four studies reporting this information. Conclusions. Endoscopic resection could be the first treatment option in patients with dNENs sized 10-20 mm and without evidence of metastatic disease. Further studies are needed to draw more solid conclusions, particularly in terms of superiority among the available endoscopic techniques.

Current status of the role of endoscopy in evaluation and management of gastrointestinal and pancreatic neuroendocrine tumors

The incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the last several decades. In general, NETs are slow-growing neoplasms and the data on the natural history is still evolving. The availability and improved utilization of advanced imaging modalities have allowed the selection of cases suitable for endotherapy. In this regard, endoscopic ultrasound (EUS) has emerged as a central imaging modality to assess the depth of infiltration in gastroduodenal as well as rectal NETs. Enhanced EUS modalities, including contrast-enhanced EUS and EUS elastography, reliably differentiate pancreatic neuroendocrine tumors (PNETs) from adenocarcinomas and may enable prediction of aggressive PNETs. With recent developments in therapeutic endoscopy, a large proportion of GEP-NETs can be safely managed endoscopically. Endoscopic resection techniques, including endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), allow the safe removal of gastroduodenal and rectal NETs. Recent data indicate that modified EMR techniques may be superior to conventional EMR with regard to histologically complete resection. Device-assisted endoscopic full thickness resection is emerging as a safe and effective technique for upper gastrointestinal as well as rectal NETs. In selected cases with PNETs, who are otherwise unfit for surgery, EUS-guided ablation is increasingly being recognized as a safe treatment option. This review focusses on evidence-based approaches to endoscopic evaluation and the management of GEP-NETs with special emphasis on recent advancements.

Diagnosis, treatment, and current concepts in the endoscopic management of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare tumors derived from the neuroendocrine cell system, which that have increased in incidence and prevalence in recent years. Despite improvements in radiological and metabolic imaging, endoscopy still plays a pivotal role in the number of GEP-NENs. Tumor detection, characterization, and staging are essential in management and treatment planning. Upper and lower gastrointestinal (GI) endoscopy is essential for correct localization of the primary tumor site of GI NENs. Endoscopic ultrasonography (EUS) has an important role in the imaging and tissue acquisition of pancreatic NENs and locoregional staging of GI neuroendocrine tumors. Correct staging and histological diagnosis have important prognostic implications. Endoscopic operating techniques allow the removal of small GI NENs in the early stage of mucosal or submucosal invasion of the intestinal wall. Preoperative EUS-guided techniques may help the surgeon locate small and deep tumors, thus avoiding formal pancreatic resections in favor of parenchymal-sparing surgery. Finally, locoregional ablative treatments have been proposed in recent studies with promising results in selected patients.

Endoscopic techniques for diagnosis and treatment of gastro-entero-pancreatic neuroendocrine neoplasms: Where we are

BACKGROUND

The correct localization of the primary tumor site and a complete histological diagnosis represent the milestones for the proper management of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs).

AIM

To analyze current evidence on the role of endoscopy in the diagnosis/treatment of GEP-NENs.

METHODS

An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published in the last 15 years, using both medical subject heading (MeSH) terms and free-language keywords: gastro-entero-pancreatic neuroendocrine neoplasms; endoscopy; ultrasound endoscopy; capsule endoscopy; double-balloon enteroscopy; diagnosis; therapy; staging.

RESULTS

In the diagnostic setting, endoscopic ultrasonography (EUS) represents the diagnostic gold standard for pancreatic NENs and the technique of choice for the locoregional staging of gastric, duodenal and rectal NENs. The diagnosis of small bowel NENs (sbNENs) has been improved with the advent of video capsule endoscopy and double-balloon enteroscopy, which allow for direct visualization of the entire small bowel; however, data regarding the efficacy/safety of these techniques in the detection of sbNENs are scanty and often inconclusive. From a therapeutic point of view, endoscopic removal is the treatment of choice for the majority of gastric NENs (type 1/2), for well-differentiated localized nonmetastatic duodenal NENs < 1 cm, confined to the submucosa layer and for < 10 mm, stage T1–T2, rectal NENs. EUS-guided pancreatic locoregional ablative treatments have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients.

CONCLUSION

Standard axial endoscopy and EUS still play a pivotal role in several GEP-NENs. Advanced techniques for increasing the rate of R0 resection should be reserved for high-volume referral centers.

Comparison of endoscopic resection techniques for duodenal neuroendocrine tumors: systematic review

Background and study aims  Regardless of size, duodenal neuroendocrine tumors (dNETs) should be considered potentially malignant. A complete resection without complications is essential to increase safety procedures. The aim of this review was to describe effectiveness and possible complications of endoscopic techniques resection for resectioning dNETs in patients with tumors ≤ 20 mm in diameter. Methods  An electronic bibliographic search was conducted using MEDLINE (via PubMed), Embase, Cochrane Central, and Google Scholar virtual databases. The types of intervention were endoscopic mucosal resection alone (EMR) or with cap (EMR-C), with a ligation device (EMR-L), with previous elevation of the tumor (EMR-I) or with endoscopic submucosal dissection (ESD); argon plasm coagulation (APC), and polypectomy. The outcome measures adopted were presence of free margin associated with tumor resection, tumor recurrence, complications (bleeding and perforation), and length of the procedure. Results  Ten publications were included with the result of 224 dNET resections. EMR alone and polypectomy resulted in the most significantly compromised margin. The most frequent complication was bleeding (n = 21), followed by perforation (n = 8). Recurrence occurred in 13 cases, the majority of those under EMR or EMR-I. Conclusions  EMR-C or EMR-I should be preferred for resectioning of dNETs. Polypectomy should not be indicated for resection of dNETs due to the high occurrence of incomplete resections. EMR alone must be avoided due a higher frequency of compromised margin and recurrent surgery. ESD was associated with no recurrence, however, but an increased occurrence of bleeding and perforation.

Rectal Endoscopic Ultrasound in Clinical Practice

PURPOSE OF REVIEW

Endoscopic ultrasound (EUS) is routinely utilized for evaluation of disorders of the lower gastrointestinal tract. In this review, we summarize the current status of rectal EUS in clinical practice and describe recent developments in diagnostic and therapeutic rectal EUS.

RECENT FINDINGS

Recent guidelines recommend rectal EUS for rectal cancer staging as a second line modality in cases where MRI is contraindicated. Forward-viewing echoendoscopes and through the scope EUS miniprobes allow for EUS imaging of lesions through the entire colon and for evaluation beyond stenoses or luminal narrowings. EUS can be used to assess perianal disease and drain pelvic abscess associated with IBD, along with newer applications currently under investigation. For rectal varices, EUS can confirm the diagnosis, assess the optimal site for banding, guide therapy placement with sclerotherapy and/or coils, and assess response to treatment by confirming absence of flow. Therapeutic rectal EUS is emerging as a promising modality for drainage of pelvic fluid collection drainage and fiducial placement for rectal or prostatic cancer. Drug delivery mechanisms and substances that may increase the scope of therapy with rectal EUS are in varying stages of development. Rectal EUS continues to be an important modality for evaluation of benign and malignant disorders of the lower gastrointestinal tract, although its use as a cancer staging modality has declined due to improvements in MRI technology. Various technologies to enhance ultrasound imaging and for therapeutics have been developed that have or may contribute to expanded indications for rectal EUS.

Clinical impact of endoscopic ultrasonography on the management of neuroendocrine tumors: lights and shadows

The incidence of gastroenteropancreatic neuroendocrine neoplasms has increased in the recent decades. An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published mostly between year 1997 and June 2017, using both medical subject heading (MeSH) terms and free-language keywords about the accuracy and diagnostic and therapeutic role of endoscopic ultrasound in the context of gastro-entero-pancreatic neuroendocrine neoplasms. Endoscopic ultrasound is the modality of choice for diagnosing pancreatic neuroendocrine neoplasms and for the locoregional staging of gastric, duodenal, pancreatic and rectal neuroendocrine neoplasms; in particular, in the setting of pancreatic neuroendocrine neoplasms it has demonstrated higher accuracy in tumor detection than other imaging modalities. Furthermore, the possibility of tattooing pancreatic lesions by endoscopic ultrasound fine needle aspiration may help surgeons to locate the tumor and avoid any demolition surgery. Finally, endoscopic ultrasound-guided therapies have been proposed and used in several studies for patients unsuitable for surgery, with good results on the control of symptoms and the reduction of tumor burden.

Advances in endoscopic ultrasound imaging of colorectal diseases

The development of endoscopic ultrasound (EUS) has had a significant impact for patients with digestive diseases, enabling enhanced diagnostic and therapeutic procedures, with most of the available evidence focusing on upper gastrointestinal (GI) and pancreatico-biliary diseases. For the lower GI tract the main application of EUS has been in staging rectal cancer, as a complementary technique to other cross-sectional imaging methods. EUS can provide highly accurate in-depth assessments of tumour infiltration, performing best in the diagnosis of early rectal tumours. In the light of recent developments other EUS applications for colorectal diseases have been also envisaged and are currently under investigation, including beyond-rectum tumour staging by means of the newly developed forward-viewing radial array echoendoscope. Due to its high resolution, EUS might be also regarded as an ideal method for the evaluation of subepithelial lesions. Their differential diagnosis is possible by imaging the originating wall layer and the associated echostructure, and cytological and histological confirmation can be obtained through EUS-guided fine needle aspiration or trucut biopsy. However, reports on the use of EUS in colorectal subepithelial lesions are currently limited. EUS allows detailed examination of perirectal and perianal complications in Crohn’s disease and, as a safe and less expensive investigation, can be used to monitor therapeutic response of fistulae, which seems to improve outcomes and reduce the need for additional surgery. Furthermore, EUS image enhancement techniques, such as the use of contrast agents or elastography, have recently been evaluated for colorectal indications as well. Possible applications of contrast enhancement include the assessment of tumour angiogenesis in colorectal cancer, the monitoring of disease activity in inflammatory bowel disease based on quantification of bowel wall vascularization, and differentiating between benign and malignant subepithelial tumours. Recent reports suggest that EUS elastography enables highly accurate discrimination of colorectal adenocarcinomas from adenomas, while inflammatory bowel disease phenotypes can be distinguished based on the strain ratio calculation. Among EUS-guided therapies, the drainage of abdominal and pelvic collections has been regarded as a safe and effective procedure to be used as an alternative for the transcutaneous route, while the placing of fiducial markers under EUS guidance for targeted radiotherapy in rectal cancer or the use of contrast microbubbles as drug-delivery vehicles represent experimental therapeutic applications that could greatly impact the forthcoming management of patients with colorectal diseases, pending on further investigations.

Review article: the investigation and management of gastric neuroendocrine tumours

BACKGROUND

Gastric carcinoids (GCs) or neuroendocrine tumours (NETs) are increasingly identified at endoscopy, and account for 0.6-2% of all gastric polyps identified. The SEER database in the US has demonstrated a rising incidence of gastric NETs amongst all NETs; from 2.2% between 1950 and 1969 to 6.0% between 2000 and 2007.

AIM

To review the literature and assist clinicians in managing patients with GCs.

METHODS

A literature search was conducted through MEDLINE using search terms: gastric, carcinoid, neuroendocrine tumour, therapy, endoscopy, mucosal resection, submucosal dissection. Relevant articles were identified through manual review. The reference lists of these articles were reviewed to include further appropriate articles.

RESULTS

There are three types of GCs with important epidemiological, pathophysiological, histological and endoscopic differences that affect prognosis and management. Type 1 and 2 GCs develop in the context of hypergastrinaemia that originates from achlorhydria in atrophic gastritis and a gastrinoma, respectively. Type 3 GCs occur sporadically and independent of gastrin. The histological type, grade and Ki67 index are used to determine prognosis and direct clinical management. Type 1 GCs >1 cm in size and type 2 GCs should be assessed for invasion beyond the submucosa with EUS prior to endoscopic resection with EMR or ESD. Type 3 GCs should be managed as per recommendations for gastric adenocarcinoma. The treatment of advanced disease is multimodal.

CONCLUSIONS

Patients with gastric carcinoids should be discussed in a specialist neuroendocrine tumour multidisciplinary meeting to ensure all treatment options are explored in localised and advanced disease. Areas of controversy exist that need further research.

Long-term results of endoscopic resection for type I gastric neuroendocrine tumors

BACKGROUND

A number of different therapies, including endoscopic resection, have been suggested for the treatment of Type 1 gastric neuroendocrine tumors (NETs). The current study aimed to determine the long-term efficacy of endoscopic resection for Type 1 gastric NETs.

METHODS

Twenty-two patients (from 1999 to 2012) with Type 1 gastric NETs were included in the study. All patients were treated with endoscopic resection and received regular followed-up appointments at a tertiary referral center.

RESULTS

All patients were initially diagnosed with hypergastrinemia, atrophic gastritis and intestinal metaplasia. Polyps' diameters were >1 cm in 4 patients, and between 0.5 and 1 cm in 18 patients. All detectable lesions were successfully resected. One patient required surgery due to gastric perforation during endoscopic mucosal resection. Recurrence was detected in four patients (18%) and endoscopic resection was performed again. Local or distant metastasis was not observed in any patient during follow-up. Median follow-up time was 7 years, with a maximum of 14 years. Seventeen patients (78%) completed a 5-year follow-up period, and overall disease-free survival rate was 100%.

CONCLUSIONS

Long-term follow-ups with 22 patients suggest that endoscopic resection of Type 1 gastric NETs is a safe and effective treatment option with a relatively low recurrence rate.

Endoscopic ultrasound in gastroenteropancreatic neuroendocrine tumors

Endoscopic ultrasound (EUS) is an advanced endoscopic technique currently used in the staging and diagnosis of many gastrointestinal neoplasms. The proximity of the echoendoscope to the gastrointestinal tract lends itself to a detailed view of the luminal pathology and the pancreas. This unique ability enables endoscopists to use EUS in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Diagnostic EUS allows previously unidentified NETs to be localized. EUS also determines tumor management by staging the GEP-NETS, enabling the clinicians to choose the appropriate endoscopic or surgical management. The ability to obtain a tissue diagnosis with EUS guidance enables disease confirmation. Finally, recent developments suggest that EUS may be used to deliver therapeutic agents for the treatment of NETs. This review will highlight the advances in our knowledge of EUS in the clinical management of these tumors.

Unusually aggressive type 1 gastric carcinoid: a case report with a review of the literature

Gastric carcinoids are rare tumors of the stomach. Gastric carcinoid type 1 is associated with chronic atrophic gastritis, and because of a low metastatic potential, is the most benign type. Death from metastatic disease has been reported in only three patients in a review including 724 cases. The present report refers to a 60-year-old man who was affected by type 2 diabetes mellitus and pernicious anemia and died from metastatic gastric carcinoid type 1. In 1998, a well-differentiated 1.2 cm gastric neuroendocrine tumor, immunoreactive for chromogranin A, with a Ki-67 index less than 2% and with infiltration to the submucosal layer was diagnosed and enucleated. In 2002, a new well-differentiated gastric endocrine tumor 6 mm in size with a Ki-67 of approximately 2% was detected, and endoscopic ultrasound confirmed it to be limited to the submucosal layer. The patient refused antrectomy and started long-acting somatostatin analog (lanreotide) in 2005 when the Ki-67 index was 7%, but he stopped the treatment after 4 months. In 2007, despite previous endoscopic stability, endoscopic ultrasound showed an infiltrating gastric lesion of 7 cm. At surgery, the disease appeared to be extended to the liver and to the peritoneum (well-differentiated endocrine carcinoma, Ki-67 40%) with both hepatic and massive peritoneal metastases. A regimen of somatostatin analog was soon restarted; however, the disease continued to spread, and the patient died 6 months later. Overall, despite their generally benign course, type 1 gastric carcinoids may have malignant potential, a finding that should be considered when planning the medical workup of these patients.

[Gastric neuroendocrine tumors. Endoscopic and surgical treatment]

Neuroendocrine tumors (NETs) of the stomach are the most frequent among all neuroendocrine neoplasms in the digestive tract. The diagnosis and classification are complicated by the fact that these tumors have to be categorized not only by common staging and grading but also according to their pathophysiological background (types). The types differ in their biological behaviour (aggressiveness) which influences therapeutic concepts. This article explains and summarizes the etiology and classification of gastric NETs and offers a precise concept for diagnosis and treatment to improve clinical outcome.