First report of a series of endoscopic intermuscular dissection for gastric neuroendocrine tumours

Aims Endoscopic submucosal dissection (ESD) has been established as a safe and effective technique for minimally-invasive resection of gastric neuroendocrine tumours (gNETs), providing a higher complete (R0) resection, when compared with endoscopic mucosal resection [1] [2] [3], and providing excellent specimen quality for accurate histopathological evaluation. However, even small, non-invasive gNETs may involve the deep submucosal layer, with associated fibrotic-tethering to the muscularis propria (MP), as a result of these lesions’ paracrine effects. Due to this tethering, a standard ESD approach runs the risk of a compromised resection (R1). In order to ensure R0 resection, we have previously described the first case of gastric endoscopic intermuscular dissection (EID) [4], through dissection of the oblique layer from the circular layer of the MP, to achieve a clear vertical dissection margin, as was previously described for rectal pathology. This small series of gastric EID reports outcomes, benefits and risks in routine clinical practice.

Methods Consecutive, prospective case-series from a single, tertiary-referral centre in the UK.

Results A total of 4 patients (M:3; F:1), with gNETs were referred to our centre for ESD. Mean age: 52.75 years (SD 16,25, range 35-68) and median ASA score: 2 (IQR 1-2, range 1-2). All lesions were located within the gastric body; median maximum diameter: 15 (IQR 12-15, range 12-15). Median resection time: 170 minutes (IQR 130-220, range 120-240). All procedures were performed with endotracheal intubation. Our saline-immersion/irrigation technique (SITE) was used and EID was applied in all cases to achieve a tumour-free resection margin, due to gNET adherence to the MP. EID was achieved in all patients with 100% R0 resection. Histopathological analysis confirmed the first two cases to be 15mm type 1 gNETs arising on a background of chronic atrophic gastritis with entero-chromaffin-like cell hyperplasia (World Health Organization (WHO) classification Grade 2). The 3^rd case was a 12mm Type 1 gNET (WHO Grade 1). The most recent EID specimen included a 1.5mm and an 11mm Type 3 gNETs (WHO Grade 2). All patients were admitted as a routine and intravenous prophylactic antimicrobials given. One adverse event was encountered: a perforation of the full-MP; this was completely closed endoscopically. Post-procedural CT-scan revealed intraperitoneal saline-leakage, warranting radiological drainage which was managed conservatively and discharged 11-days post-EID. The remaining patients were discharged after 72-hours without any adverse events.

Conclusions SITE-EID is a feasible technique for gNETs when deeper excisions margins are required to achieve R0 resection, avoiding the need for invasive surgery. SITE facilitates this technically demanding procedure through enhanced visualization and buoyancy. Any intra-peritoneal leakage of saline through inadvertent full-thickness defects may be easily managed with drainage rather than surgery. Further study is merited.

Publication History

Article published online:
27 March 2025

• References

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