Published online Jul 14, 2022. doi: 10.3748/wjg.v28.i26.3258
Peer-review started: October 27, 2021
First decision: December 27, 2021
Revised: January 4, 2022
Accepted: April 15, 2022
Article in press: April 15, 2022
Published online: July 14, 2022
Processing time: 258 Days and 15.3 Hours
The prognosis of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) is widely variable depending on several factors including the site of the primary tumor, the grading, and the stage. The correct localization of the primary tumor site, as well as a complete histologic diagnosis, represent the milestones for the proper management and the prognosis of these tumors. Standard axial endoscopy and endoscopic ultrasonography (EUS) still play a pivotal role in several GEP-NENs.
The incidence of GEP-NENs has hugely increased over the last decades; given the well-known heterogeneity of these tumors and the lack of large prospective studies, there is an urgent need to standardize their management.
To analyze current evidence on the role of endoscopy in the management of GEP-NENs (both diagnosis and potential treatment). A specific focus will be reserved to capsule endoscopy, double-balloon enteroscopy and ultrasound endoscopy.
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.
EUS represents the diagnostic gold standard for pancreatic NENs (panNENs) and the technique of choice for the locoregional staging of gastric, duodenal and rectal NENs. EUS proved to be the most accurate diagnostic technique in panNEN detection. EUS–fine needle aspiration is a diagnostic advanced EUS technique, which represents the gold standard least invasive option to obtain the histological identification of a suspected pancreatic neoplasm or peripancreatic lymph node. The diagnosis of small bowel NENs (sbNENs) has been improved with the advent of capsule endoscopy (CE) and double-balloon enteroscopy (DBE), even if data regarding the efficacy and safety of these techniques in the detection of sbNENs are scanty and mainly based on small retrospective series, given the rarity of the disease and the still-limited use of these techniques in routine clinical practice. In selected localized gastrointestinal NENs with the absence of features associated with lymph node metastases, endoscopic therapy is generally an appropriate treatment with radical intent. In highly selected G1 or low G2 small neoplasms without radiological signs suspicious for malignancy EUS-guided pancreatic locoregional ablative treatments, using either ethanol injection or radiofrequency ablation, have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden.
Endoscopy plays a key role in GEP-NENs for both the diagnosis and the treatment. In selected localized GEP-NENs, endoscopic therapy is appropriate with radical intent. The multidisciplinary management and the referral to high-volume tertiary centers remain fundamental.
Further studies are needed: (1) To better define the actual role of CE and DBE in the diagnosis of sbNENs; and (2) To better analyze the possible role of endoscopic confocal laser endomicroscopy in the diagnosis of panNENs and radiofrequency ablation as a potential treatment. Possible future intriguing perspectives can be represented by the application, also in panNENs, of the novel techniques of locoregional delivery of drugs.