Endoscopic management of difficult laterally spreading tumors in colorectum

Table 2 Steps for endoscopic mucosal resection of laterally spreading tumors

Steps for endoscopic resection
(1) Endoscopic evaluation	Using Paris classification, pit pattern and vascular pattern to characterize the lesions and define the risk of deep SMI
(2) Strategy	Decide en bloc vs piecemeal resection according to risk of SMI. Consider patient position and gravity
(3) EMR technique
Injection	Needle tangential to the plane. Inject whilst “stabbing” the mucosa helps accurately find the SM plane. Use a dynamic injection technique
Resection	Put the area to resect ideally between 5-6 o’clock (with colonoscope); accommodate the snare over the lesion and push “down,” aspirate to decrease tension and maximize tissue capture; close the snare tightly; check for mobility and degree of closure of the snare handle (usually < 1 cm distance between thumb and fingers), be sure there is no muscle trapped, otherwise release the tissue (in case of doubt, open and close the snare to “drop out” possible muscular entrapment); press the pedal to resect
Wash and check mucosal defect	Check the mucosal defect produced to rule out signs of muscle layer damage or perforation
Hemostasis	If there is mild intraprocedural bleeding, try first snare tip soft coagulation. If necessary, coagulating forceps or clips can be helpful
Systematic inject and resect	Continue resection injecting when necessary to maintain submucosal cushion. Resect 2-3 mm of normal mucosa to ensure margins. Try not to leave islands or bridges between resections
(4) UEMR technique
Water filling	Aspirate all the gas and fill the lumen of the working space with water or saline (turning off insufflation may help) to create a gravity-free environment
Resection	Put the area to resect ideally between 5-6 o’clock (with colonoscope); accommodate the snare over the lesion “torque and crimp” and push “down” to get the floating lesion inside the snare; aspirate and irrigate more water to help the capture of the tissue; close the snare tightly and separate the tissue from the wall. Press the pedal to resect. Underwater, higher outputs might be needed for resection/coagulation due to the heat sink effect
Wash and check mucosal defect	Check the mucosal defect produced to rule out signs of muscle layer damage or perforation. As no dye is used to stain the submucosa, the operator should become familiarized with the aspect of the “transparent” fibers
Hemostasis	In cases of jet bleeding gas insufflation might be needed to find the bleeding point
Systematic gas aspiration water irrigation and resection	Continue resection aspirating gas or irrigating water when necessary. Resect 2-3 mm of normal mucosa to ensure margins. Try not to leave islands or bridges between resections
(5) Final inspection	Check the scar to rule out residual neoplastic tissue or signs of deep injury. In cases of piecemeal resection, thermal ablation with the tip of the snare (Soft COAG 80 W) to coagulate the mucosal borders of the scar reduces risk of recurrence
(6) Specimen retrieval and assessment	Consider using a net for retrieval. Big nodules should be sent separately if it was piecemeal resection

EMR: Endoscopic mucosal resection; SM; Submucosal; SMI: Submucosal invasion; UEMR: Underwater endoscopic mucosal resection