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.

Localized Well-Differentiated Rectal Neuroendocrine Tumors - Where Are We in 2021?

Neuroendocrine tumors (NETs) are slow-growing malignancies with distinct biologic and clinical characteristics. Most rectal-NETs are localized and well-differentiated, usually carrying an excellent prognosis. In this review, we aim at describing the epidemiology, clinical characteristics and therapeutic approaches for well-differentiated rectal NETs.

Successful outcomes of EMR-L with 3D-EUS for rectal carcinoids compared with historical controls

AIM: To assess the results of endoscopic mucosal resection with a ligation device (EMR-L) combined with three dimensional endoscopic ultrasonography (3D-EUS) using an ultrasonic probe for rectal carcinoids. In addition, diagnosis of the depth and size of lesions by EUS was evaluated.

METHODS: Between January 2003 and March 2007, 20 patients underwent EMR-L with 3D-EUS using an ultrasonic probe (group A). 3D-EUS was combined with EMR-L at the time of injection of sterile physiological saline into the submucosal layer. For comparison, 14 rectal carcinoids that had been treated by EMR-L without 3D-EUS between April 1998 and December 2002 were evaluated as historical controls (group B). EUS was conducted for all of the patients before treatment to evaluate tumor diameter and depth of invasion. The percentage of complete resection and the vertical resection margin were compared between the two groups.

RESULTS: The depth of invasion upon histopathological examination was in complete agreement with the pre-operative findings by EUS. The tumor diameter determined by EUS approximated that found in the tissue samples. There were no significant differences in the gender, tumor sites or tumor diameters between the two groups. The rate of complete resection for groups A and B was 100% and 71%, respectively (P < 0.05). The vertical resection margin of group A was longer than that of group B.

CONCLUSION: EMR-L is effective as an endoscopic treatment for rectal carcinoids. In combination with 3D-EUS, safe and complete resection is further assured.