Section 1: Lesion Lifting
1. When evaluating a lesion, what specific criteria guide your decision between proceeding with endoscopic removal and recommending surgery?
The main indication for direct referral to surgery is the presence of vascular and surface pit structure disruption. These features are captured in NICE (Narrow band imaging International Endoscopic classification) 3, JNET (Japan Narrow band imaging Expert Team classification) 3 and Kudo 5. When present these features are typically accompanied by some degree of depressed morphology. These features are not highly sensitive for cancer but are very specific for cancer with at least deep submucosal invasion. Traditionally, deep submucosal invasion has been considered a strong predictor of lymph node metastasis. If these changes are present over an area that is more than 5 to 10 mm wide, the best approach is to biopsy that specific area of vascular and disruption which will document the presence of cancer and then send the patient to surgery.
In recent years we have seen considerable evidence, primarily from Europe, that if deep submucosal invasion is present but there are no other adverse histologic features (poor differentiation, lymphovascular invasion, or high-grade tumor budding), then the risk of lymph node metastasis is actually quite low. In one meta-analysis the risk of lymph node metastasis with isolated deep submucosal invasion as the only adverse histologic feature was only 2.6%. Therefore, if the area of vascular and surface pit disruption is present only over a few millimeters, then endoscopic resection may still be appropriate. However, the method of endoscopic resection must be carefully considered. The area of vascular and pit disruption should be resected en bloc, and consideration of endoscopic full-thickness resection of this area is appropriate.
In the absence of these changes, most lesions in the colorectum are candidates for endoscopic resection.
2. When you think about the “perfect lift” during EMR, what characteristics are you looking for immediately after injecting EverLift?
Submucosal injection prior to snare resection should always be performed with the thought and intent that the injection will facilitate the snare resection, i.e. make it easier. The ideal lift is one that builds vertically and does not spread excessively in the lateral directions, is relatively persistent in that it does not diffuse away quickly, is reasonably soft so that it can be indented easily with the snare, and has enough blue contrast to clearly delineate the lesion margin and to strongly stain the submucosa for easy inspection during the resection. EverLift is a great combination of these features, and I use it routinely for EMR.
3. What are the most common mistakes you see clinicians make with needle positioning during EverLift injection, and how does this affect the quality of the lift?
First, it helps to approach the lesion tangentially rather than en face whenever possible. The tangential approach makes it easier to find the submucosa. Second, 25-gauge needle makes it easier to enter the submucosa without pushing through the wall. The 23-gauge needle requires more pressure to push through the mucosa and that extra pressure is more likely to result in the needle passing entirely through the wall of the colon. Once the needle is inserted, if the entire needle has disappeared, it is quite possible that the needle tip is through the wall, especially with an en face approach. So it is often helpful to pull a Foley inserted needle back to a more superficial position before starting the injection.
When actual injection is started, the assistant should push only a small amount of fluid, and if no submucosal bleb appears, the needle is repositioned, followed by injection of another small amount of fluid. This process continues until the submucosal bleb begins to develop, and then injection can proceed more rapidly.
4. For flat lesions in the 10-30mm range, you recommend a centralized “dome” injection. How does your approach change if the lesion demonstrates partial non-lifting despite an appropriate injection?
The location of the first injection should be carefully planned. Were lesions in the 10 to 30 mm size range, the injection should usually be near the center of the lesion so that the lesion ends up on top of a submucosal mound created by a single injection. Ideally the injection mound will have spread at least a few millimeters beyond all borders of the lesion. If the submucosal mound develops asymmetrically, lifting one side of the lesion more than another, then stop and move the needle to a new position. This position should usually be into the edge of the already created blue submucosal injection mound that is closest to the portion of the lesion not yet lifted. Try to avoid starting additional injections in areas where there is no submucosal fluid, but this requires finding the submucosal space again. In the absence of overt cancer, there is no contraindication to injecting through the lesion.
If the lesion is draped over a haustral fold, so that the portion of the lesion on the cecal side of the fold is not visible, then the best strategy is often to make the initial injection on the cecal edge of the lesion. In some cases this will be easier in retroflexion.
If the lesion is 40 mm or larger or extends over multiple haustral folds, it is often preferable to inject a portion of the lesion on the rectal side, snare resect that portion, and then reinject, moving progressively from the rectal side toward the cecal side.
In modern practice, the most common reason by far for non-lifting is previous manipulation of the polyp. This is most likely to be created by previous partial resection, but flat polyps may have poor lifting simply from previous biopsy, and occasionally poor lifting results from previous submucosal tattoo. In lesions that have not been previously manipulated, non-lifting can be caused by tumor invasion, and in that case proceeding with endoscopic resection may not be appropriate.
Section 2: Tattooing Technique
5. What tattooing errors do you see most often that you wish every endoscopist could avoid?
The most common error is letting the tattoo get under the lesion. This is avoided by placing the tattoo 3 to 5 cm from the lesion and come injecting an appropriate amount. With a concentrated tattoo like SPOT-EX only 0.5 to 0.75 ml into the submucosal space is needed to make an endoscopically easily visible tattoo. Always make a note in the report about where the tattoo is in relationship to the lesion. For example, “the tattoo was placed 5 cm distal to the lesion on the same wall”.
The other common mistake is to place tattoos where they are not needed. In general, tattoos are not needed in the cecum or proximal ascending colon. The position of the lesion can be documented for future reference by a photograph showing the position of the lesion in relationship to a fixed anatomical location such as the appendiceal orifice or ileocecal valve. Tattoos are also generally unnecessary in the rectum.
6. What details do you find most crucial to document or communicate to surgeons or endoscopists so they can interpret the tattoo correctly?
When a tattoo was placed, the report should document the amount of tattoo placed and the specific location of the tattoo in relationship to the lesion. Generally, I prefer that for both lesions referred for surgery or for subsequent endoscopic resection, the tattoo be placed distal to the lesion. For surgery, tattoos should be placed in 3 or 4 quadrants and distal to the lesion.
During surgery, the surgeon must find the tattoo in the wall of the colon. The surgeon should never rely on tattoo in other organs or in the peritoneal cavity. If the tattoo cannot be located during surgery, the surgeon should not rely on the endoscopist’s report of tumor location if that location is transverse, descending, or proximal sigmoid. Obese men often have a lot of serosal fat, and a higher tattoo volume can be helpful for locating the tattoo during surgery. If the endoscopist notices tattoos other than the tattoo marking the lesion for intended surgery, it is very helpful to communicate this to the surgeon so that the surgeon is aware of the potential of a misleading tattoo. Finally, if the surgeon cannot locate the tattoo intraoperatively, then an intraoperative colonoscopy by the surgeon or the gastroenterologist on-call should be performed to locate the lesion.
7. Tattooing 3 – 5 cm distal to the lesion is standard, but this can be challenging depending on the patient’s anatomy and lesion location. How do you adjust tattoo placement when the lesion is near a flexure or difficult-to-orient segments?
The key to successful tattooing is to create a good submucosal bleb. The exact distance from the tumor is less critical. Find the location where you can make a good tangential approach to the mucosa and inject there. If this ends up being a bit further than 3 to 5 cm distal to the tumor it is fine. Just give a good description in the report of how far and where the tattoo is in relationship to the lesion.
8. From a long-term surveillance standpoint, how important is it to be able to reliably locate the lesion in follow up procedures and how does Spot Ex enable this?
Surveillance has two purposes. One is to identify the EMR site and determine if there is a recurrence, and remove any recurrence that is present. The other purpose is to make sure that all synchronous disease is cleared from the colon.
For the first purpose, the tattoo is very valuable. The tattoo is particularly valuable when the report from the EMR states very clearly the position of the tattoo in relationship to the EMR defect. EMR defects but are most easily visualized with the colon fully distended. Developing skill and identifying EMR scars is an important goal for every colonoscopy is to performs EMR.
