Evolving role of the endoscopist in management of gastrointestinal neuroendocrine tumors

Abstract

Neuroendocrine tumors (NETs) are uncommon gastrointestinal neoplasms but have been increasingly recognized over the past few decades. Luminal NETs originate from the submucosa of the gastrointestinal tract and careful endoscopic exam is a key for accurate diagnosis. Despite their reputation as indolent tumors with a good prognosis, some NETs may have aggressive features with associated poor long-term survival. Management of NETs requires full understanding of tumor size, depth of invasion, local lymphadenopathy status, and location within the gastrointestinal tract. Staging with endoscopic ultrasound or cross-sectional imaging is important for determining whether endoscopic treatment is feasible. In general, small superficial NETs can be managed by endoscopic mucosal resection and endoscopic submucosal dissection (ESD). In contrast, NETs larger than 2 cm are almost universally treated with surgical resection with lymphadenectomy. For those tumors between 11-20 mm in size, careful evaluation can identify which NETs may be managed with endoscopic resection. The increasing adoption of ESD may improve the results of endoscopic resection for luminal NETs. However, enthusiasm for endoscopic resection must be tempered with respect for the more definitive curative results afforded by surgical treatment with more advanced lesions.

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

“…In meta-analyses[166,169], EUS had pooled sensitivity of 87–97% for detecting a panNET and a specificity of 98%. It also allows for assessment of lesion depth, invasiveness, and presence of lymphadenopathy[170]. Furthermore, EUS allows for the evaluation of cystic panNETs which will be briefly discussed later in this article[48].…”

“…), as well as in patients with small sporadic NF-panNETs, who are being followed, each of which will be discussed in more detail below. Fourth, it allows EUS-directed cytology or biopsies to be performed, which can confirm the histology of the lesion as well as provide grading of the NET[48,170]. Lastly, it can have a therapeutic option in patients with functional NETs such as insulinomas, where surgery is not considered, by allowing EUS-administered cytotoxic agents such as ethanol, which can control the hormone-excess state[6,171].…”

“…On EUS higher grade panNETs were more likely to be large≥20mm), heterogeneous and have obstruction of the pancreatic duct[174,177]. In recent studies the sensitivity of EUS-FA for diagnosing panNETs is reported to be 84–90%[170,173,179], specificity(99%)[179] and the concordance between the WHO tumor grade between surgical and EUS-FA specimens was 64–88%%[172–175,177,180,181]. The concordance rate on EUS-FNA samples compared to surgical samples varied with panNET size being 88–95%% for panNETs<20 mm, but only 7–57% for panNETs≥20mm[174,177] and also was more accurate when larger number of cells(>2000) were counted[174,175,181].…”

Combination of laparoscopy and endoscopy as an option for treatment patients with gastric neuroendocrine tumors

“…In spite of a wide numbers of studies, there is still no universal position in treatment of small (<20 mm) gastric NETs. Some surgeons prefer to follow up without surgery, another ones consider surgical treatment [2, 3]. Combination of laparoscopy and gastroscopy can be an optional approach in treatment of patients with multiple gastric NETs.…”

Evaluating the ACS-NSQIP Risk Calculator in Primary GI Neuroendocrine Tumor: Results from the United States Neuroendocrine Tumor Study Group

“…10 Surgical techniques include minimally invasive strategies such as endoscopy, laparoscopy, or robotic surgery, as well as traditional open surgery. [11][12][13] Despite advances in surgical technique, resection of localized GI-NET does carry risk of adverse events. These complications include but are not limited to SSI, UTI, intra-abdominal bleeding, and bowel obstruction, perforation, or necrosis.…”