Does hyaluronic acid stimulate tumor growth after endoscopic mucosal resection?

Submucosal injection fluid and tattoo agents

BACKGROUND AND AIMS

EMR and endoscopic submucosal dissection (ESD) are minimally invasive endoscopic techniques, developed for the removal of benign and early malignant lesions throughout the GI tract. Submucosal injection of a marking agent can help to identify lesions during surgery. Endoscopic resection frequently involves "lifting" of the lesions by injection of a substance within the submucosal space to create a cushion for safe resection. This review summarizes the current techniques and agents available for endoscopic marking and lifting of GI tract lesions.

METHODS

The MEDLINE database was searched through April 2023 for relevant articles related to the lifting and marking aspect of EMR by using key words such as "endoscopy" or "endoscopic" combined with "marking," "tattoo," and "lifting." The report was drafted, reviewed, and edited by the American Society for Gastrointestinal Endoscopy Technology Committee and approved by the Governing Board of the American Society for Gastrointestinal Endoscopy.

RESULTS

This technology review describes the techniques for endoscopic tattoo placement and submucosal lifting, along with currently available agents, safety, and costs.

CONCLUSIONS

Endoscopists performing EMR and ESD have several choices in submucosal injection materials for lifting and marking agents for tattoos. These may be commercially prepared agents or off-the-shelf materials with or without additives to facilitate visualization. A thorough understanding of the indications, techniques, properties of various agents, costs, and adverse events is necessary in choosing the appropriate materials and technique to optimize lesion resection in EMR and ESD.

Solutions for submucosal injection in endoscopic resection: a systematic review and meta-analysis

BACKGROUND AND AIMS

Submucosal injection is standard practice in endoscopic mucosal resection of gastrointestinal lesions. Several solutions are used. Our aim was to systematically review their efficacy and safety.

PATIENTS AND METHODS

We performed a systematic review and meta-analysis using a random effects model of randomized controlled trials (RCTs) from MEDLINE. Studies in animal models were qualitatively assessed for efficacy and safety.

RESULTS

In total, 54 studies were qualitatively assessed. Eleven RCTs were analyzed, two of which were on endoscopic submucosal dissection (ESD). The quantitative synthesis included nine RCTs on endoscopic mucosal resection (EMR), comprising 792 subjects and 793 lesions. Mean lesion size was 20.9 mm (range 8.5 - 46 mm). A total of 209 lesions were randomized to sodium hyaluronate (SH) vs normal saline (NS), 72 to 50 % dextrose (D50) vs NS, 82 to D50 vs SH, 43 to succinylated gelatin, 25 to hydroxyethyl starch and 36 to fibrinogen. In total, 385 were randomized to NS as controls. NS and SH are the best studied solutions and seem to be equally effective in achieving complete resection (OR 1.09; 95 %CI 0.82, 1.45). No solution was proven to be superior in complete resection rate, post-polypectomy bleeding or coagulation syndrome/perforation incidence. Many solutions have been tested in animal studies and most seem more effective for mucosal elevation than NS.

CONCLUSIONS

There are several solutions in clinical use and many more under research, but most are poorly studied. SH seems to be clinically equivalent to NS. There are no significant differences in post-polypectomy complications. Larger RCTs are needed to determine any small differences that may exist between solutions.

Endoscopic resection for gastrointestinal neuroendocrine tumors

Gastrointestinal (GI) and neuroendocrine tumors (NETs) can be treated by mini-invasive endoscopic resection when localized in the superficial layers of the bowel wall and their size is <20 mm. Endoscopic diagnosis of NETs is usually incidental or suspected after clinical, laboratory or imaging findings. Endoscopic mucosal resection is the most commonly used technique for NET removal, endoscopic submucosal dissection is indicated in selected cases, while papillectomy is feasible for ampullary lesions. Histopathologic assessment of the resection margin (circumferential and deep) is important for staging. Incidence of endoscopic mucosal resection-/endoscopic submucosal dissection-related complications for removal of GI NETs are similar to those reported for other GI lesions. Endoscopic follow-up is based on histopathologic characteristics of the resected NETs and its site. NETs >20 mm in size, with penetration of the muscle layer and/or serosa are at high risk for metastases and surgical approach is recommended when feasible.

Efficacy of submucosal injection of different solutions inclusive blood components on mucosa elevation for endoscopic resection

Background

Endoscopic resection has become the standard treatment for noninvasive gastrointestinal malignancies. In flat mucosal tumors, normal saline is frequently used for submucosal fluid injection in order to reduce the risk of complications during endoscopic resection. Recent studies have demonstrated longer-lasting mucosa elevation by injection of agents such as hyaluronic acid or glyceol, rather than normal saline. We investigated the efficacy of different blood components in comparison with other solutions for use as a submucosal fluid cushion.

Methods

Normal saline, sodium hyaluronate, glyceol, hydroxyethyl starch, serum, plasma, and whole blood were evaluated for their effectiveness in creating a submucosal cushion. One milliliter of each solution was injected into the submucosa of 5 × 5 cm specimens of resected porcine stomach. Mucosa elevation was measured before and up to 60 minutes after injection.

Results

The shortest duration of mucosa elevation was observed after injection of normal saline, glyceol, and 0.125% hyaluronic acid. A significantly longer duration was obtained after injection of hydroxyethyl starch, 0.25% and 0.5% hyaluronic acid, serum, and plasma. However, whole blood generated a longer-lasting mucosa elevation than all other agents.

Conclusion

The results of the current study suggest that whole blood is more effective in generating long-lasting mucosa elevation than any other commonly used solution. Because autologous blood is readily available at almost no cost, this seems to be an optimal agent for creating the mucosa elevation needed for endoscopic resection. Further in vivo studies in humans are needed to clarify the potential role of autologous blood for long-lasting endoscopic mucosa resection or endoscopic submucosal dissection.