Recent advances in endoscopic management of gastric neoplasms

Table 1 Endoscopic ultrasonography features of subepithelial tumors

Subepithelial tumor	Endoscopic ultrasound layer	Histological layer	Echogenicity	Shape	Other features
Gastrointestinal stromal tumor	4th	Muscularis propria	Hypo	Irregular or round	Heterogenous, marginal halo, cystic spaces, lymphadenopathy
Leiomyoma	2nd or 4th	Deep mucosa or muscularis propria	Hypo	Round	Homogenous, fine margins
Neuroendocrine tumor (carcinoid)	2nd	Deep mucosa	Hypo or iso	Round, sessile or polypoid	Erythematous depression or ulceration, smooth margin
Lipoma	3rd	Submucosa	Hyper	Round	Homogenous
Schwannoma	4th	Muscularis propria	Hypo	Round	Heterogenous, exophytic
Granular cell tumor	2nd	Deep mucosa	Hypo	Round	Homogenous, fine margins
Inflammatory fibroid polyp	2nd	Deep mucosa	Hypo	Irregular	Heterogenous, diffuse margins
Ectopic pancreas	2nd, 3rd or 4th	Depending on layer	Mixed	Irregular	Ductal structure, anechoic microcysts

Table 2 Common endoscopic knives used for gastric endoscopic submucosal dissection

Endo knife type	Name (manufacturer)	Advantages	Disadvantages
Insulated tip knife	IT knife (Olympus, Tokyo, Japan)	Less risk of muscle layer injury and perforation due to ceramic insulated tip, more suitable for submucosal dissection. Can be used for hemostasis	Cannot be used for marking, precutting or injection. More difficult to maneuver. Pull-cut limits direction of incision. Cutting performance tends to deteriorate in cases with severe fibrosis such as ulcer scars. Lateral cutting is difficult as the ceramic tip at the distal end catches in the mucosa. Laying the knife down too much increases the risk of perforation
	IT knife 2 (Olympus, Tokyo, Japan)	Improved incision and cutting performance in lateral cutting and fibrotic tissue with three blades attached to the back of the insulated ceramic tip. Faster incision and cutting, shorter operating time compared to IT knife. Safer than dual knife for beginners	Needle knife for marking, precutting and injection. Difficult to manipulate in cardia and greater curvature of upper body. Sharper than IT knife which may increase the risk of perforation if firm pressure or too much downward angle is used. Needs more gentle manipulation than IT knife
Needle knife	Dual knife (Olympus, Tokyo, Japan)	Easy to maneuver. Can be used for all steps of ESD: Marking, injection, incision, dissection and hemostasis. Offers more precise fine incision with better cutting performance on fibrotic tissue and ulcer scar	Higher risk of perforation when dissecting close to the muscularis propria, especially since the tip of the electrode is exposed (not insulated)
Scissor knife	SB knife (Sumitomo Bakelite, Tokyo, Japan)	External insulation, curved blades to protect muscle layer with reduced risk of perforation for gastric lesions. Superior safety profile. Rotatable to adjust cutting line. Useful to cut the fibrotic tissue. Sufficient coagulation before incision to minimize bleeding. Suitable for trainees	Cannot control severe bleeding. Discontinuous cutting
	Clutch cutter (Fujifilm, Japan)	Scissor-type knife similar to SB knife. More secure incision. Serrated cutting edge enables more efficient bleeding control than SB knife. Better self-completion rates and shorter procedure times for gastric ESD by nonexperts than IT2, probably due to hemostatic efficacy	Thicker than SB knife, cannot make a sharp mucosal incision as SB knife
Waterjet knife	Hybrid knife (Erbe, Germany)	Waterjet knife with needleless injection. Multi-function probe, can be used for all steps of ESD. Shorter procedure time compared to non-waterjet knives. Lower risk of bleeding by water cushion. Three types with different functionalities	Requires ERBEJET® 2 hydro surgery system. More costly
RFA knife	Speedboat (Creo Medical, United Kingdom)	Multi-function probe, integrated injection needle, able to complete the entire procedure with a single instrument. Only bipolar RFA knife in the market, no grounding needed. RF cutting with lower voltage and minimal bleeding. Microwave coagulation with possibly lower rates of post polypectomy syndrome. Potentially faster procedure	Requires therapeutic scope with at least 3.7 mm accessory channel

ESD: Endoscopic submucosal dissection.