Endoscopic management of difficult laterally spreading tumors in colorectum

Table 1 Considerations for endoscopic treatment in laterally spreading tumors

LST suitable for piecemeal EMR	Comments	LST not suitable for piecemeal EMR	Comments
LST-G homogeneous type	Very low risk for deep SMI, independent of size of the lesion	LST-NG pseudodepressed type	En bloc resection
LST-G mixed nodular type with no signs of SMI	Consider en bloc resection first. If not, careful inspection of surface/pit pattern and vascular pattern specially in the larger nodules (≥ 10 mm), resect the nodular area apart (e.g., JNET2a)	LST-G mixed nodular or NG flat with risk of SMI	En bloc resection (e.g., JNET2b, pit pattern V)
LST-NG flat with no demarcated area and no signs of SMI	Consider en bloc resection first. If not, careful inspection of surface/pit pattern and vascular pattern (e.g., JNET2a)

EMR: Endoscopic mucosal resection; G: Granular type; JNET: Japan Narrow Band Imaging Expert Team; LST: Laterally spreading tumor; NG: Non-granular type; SMI: Submucosal invasion.

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

Table 3 Sydney Classification of deep mural injury

Sydney Classification of deep mural injury
Type 0	Normal defect. Blue mat appearance of obliquely oriented intersecting submucosal connective tissue fibers (with a blue dye such as indigo carmine or methylene blue)
Type 1	MP visible but no mechanical injury (“Whale” sign)
Type 2	Focal loss of the submucosal plane raising concern for MP injury or rendering the MP defect uninterpretable
Type 3	MP injured, specimen target sign or defect mirror target sign identified
Type 4	Actual hole within a white cautery ring, no observed contamination
Type 5	Actual hole within a white cautery ring, observed contamination

MP: Muscular propria.

Table 4 Spanish Score for risk of bleeding after endoscopic mucosal resection

	Age ≥ 75-yr-old	Lesion ≥ 40 mm	ASA III-IV	Location proximal to transverse colon	Aspirin	Clips
Yes	1	1	1	3	2	0
No	0	0	0	0	0	2
Risk of bleeding after EMR
Low risk 0.6% (0.2%-1.8%)	0-3 points
Medium risk 5.5% (3.8%-7.9%)	4-7 points
Elevated risk 40% (21.8%-61.1%)	8-10 points

ASA: American Society of Anesthesiologists classification of physical health; EMR: Endoscopic mucosal resection.

Table 5 Sydney endoscopic mucosal resection recurrence tool

Risk factor	Score
LST size ≥ 40 mm	2
IPB requiring endoscopic control	1
High-grade dysplasia	1
Total	4
Cumulative incidence of EDR% (standard error)
SERT = 0	9.8% (2.2); 6 mo FU
	11.6% (2.5); 18 mo FU
SERT = 1-4	23.0% (2.5); 6 mo FU
	36.3% (3.2); 18 mo FU

EDR: Endoscopically determined recurrence; FU: Follow-up; IBP: Intraprocedural bleeding; LST: Laterally spreading tumor; SERT: Sydney endoscopic mucosal resection recurrence tool.