Advanced Endoscopic Resection of Colorectal Lesions




Advanced endoscopic resection techniques allow curative treatment of difficult colonic lesions and avoid the need for surgery in certain cases. If endoscopic resection is indicated, the choice of the most appropriate resection technique depends on lesion characteristics and endoscopist expertise.


Key points








  • Advanced endoscopic resection techniques represent the most cost-effective option for the management of difficult colorectal lesions.



  • Proficiency in optical diagnosis, techniques to prevent complications and to resect are key to the management of complex colorectal lesions.



  • All the team members should fully understanding the techniques and equipment needed to perform them.






Introduction


Recent advances in endoscopic imaging and resection allow clinicians to identify and determine lesions that are amenable to curative resection and apply techniques that ensure their complete and safe resection, while referring cancer-harboring lesions to surgery. However, these developments occurred after many clinicians finished training in an era in which lesions were described as either pedunculated or sessile and treated with a hot snare, without the benefit of image enhancement, resection, hemostatic, and closure techniques that developed in the last decade. Current therapeutic colonoscopists should be able to make an optical diagnosis of the lesion and apply the most appropriate technique to remove the lesion completely and safely. Based on our practice, this article shares our views on advanced endoscopic resection of colorectal lesions ( Box 1 ). It focuses on the resection of the nonpolypoid colorectal neoplasm (NP-CRN) because of its importance and because its resection often requires advanced techniques.



Box 1





  • Nonpolypoid colorectal neoplasms



  • Lesions greater than 2 cm



  • Difficult locations




    • Dentate line



    • Ileocecal valve



    • Appendiceal orifice



    • Folds




  • Lesions over scars



  • Lesions in chronic inflammatory bowel disease



  • Large pedunculated lesions



  • Rectal carcinoids



  • Large lipomas



  • Patients with impaired coagulation




    • Anticoagulation medication



    • Antiplatelet medication



    • Thrombocytopenia




Indications for advanced endoscopic resection in the colon




Introduction


Recent advances in endoscopic imaging and resection allow clinicians to identify and determine lesions that are amenable to curative resection and apply techniques that ensure their complete and safe resection, while referring cancer-harboring lesions to surgery. However, these developments occurred after many clinicians finished training in an era in which lesions were described as either pedunculated or sessile and treated with a hot snare, without the benefit of image enhancement, resection, hemostatic, and closure techniques that developed in the last decade. Current therapeutic colonoscopists should be able to make an optical diagnosis of the lesion and apply the most appropriate technique to remove the lesion completely and safely. Based on our practice, this article shares our views on advanced endoscopic resection of colorectal lesions ( Box 1 ). It focuses on the resection of the nonpolypoid colorectal neoplasm (NP-CRN) because of its importance and because its resection often requires advanced techniques.



Box 1





  • Nonpolypoid colorectal neoplasms



  • Lesions greater than 2 cm



  • Difficult locations




    • Dentate line



    • Ileocecal valve



    • Appendiceal orifice



    • Folds




  • Lesions over scars



  • Lesions in chronic inflammatory bowel disease



  • Large pedunculated lesions



  • Rectal carcinoids



  • Large lipomas



  • Patients with impaired coagulation




    • Anticoagulation medication



    • Antiplatelet medication



    • Thrombocytopenia




Indications for advanced endoscopic resection in the colon




Resection of NP-CRN


Characterization of NP-CRN


Endoscopic characterization of the colorectal lesion is the first step in the assessment of whether a lesion is a candidate for curative endoscopic resection. This characterization can be undertaken using the shape of the lesion (macroscopic characterization) as well as the mucosal surface pit pattern and vascular pattern (microscopic characterization). Lesions amenable for curative resection are those limited to the mucosa and, perhaps, superficial submucosa, whereas those extending to deep submucosa are not candidates for endoscopic resection.


Macroscopic characterization


Macroscopic characterization of a lesion provides information about its endoscopic appearance, its malignant potential, and the skill level required for its resection. There are 2 macroscopic types: (1) type 0, the superficial lesions; and (2) types 1 to 5, the advanced cancers ( Box 2 ). Type 0 includes the colorectal polyps, herein called lesions because the term polyp connotes abnormal growth of tissue projecting from mucous membrane. Type 0 can be classified into protruding or polypoid, and nonprotruding or nonpolypoid. Polypoid lesions are further subtyped into pedunculated (0–Ip) and sessile (0–Is). Nonpolypoid lesions can be subtyped into the superficial elevated (0–IIa), flat (0–IIb), and depressed (0–IIc) types. In the colon and rectum, the superficial elevated types are commonly classified together with flat lesions because of their shapes being tabletop flat, and because the true colorectal flat (0–IIb) lesions are rare. Flat colorectal neoplasms equal to or larger than 10 mm are called lateral spreading tumors (LSTs). LSTs are differentiated into granular LST (LST-G) and nongranular LST (LST-NG).



Box 2





  • Type 0: lesions with superficial appearance




    • 0 to I: Protruding




      • 0 to Is: Sessile



      • 0 to Ip: Pedunculated




    • 0 to II: Nonprotruding and nonexcavated




      • 0 to IIa: Slightly elevated



      • 0 to IIb: Flat



      • 0 to IIc: Slightly depressed



      • 0 to IIa + IIc, 0 to IIc + IIa: Elevated and depressed




    • 0 to III: Excavated




  • Type 1 to 5: lesions with muscularis propria involvement



Paris/Japanese classification


Macroscopic characterization provides superior information about the risk of early cancer compared with size of the lesion. NP-CRNs have higher risk of early cancer than the polypoid-CRNs, irrespective of size. The observation that the larger the polypoid neoplasms the higher the risk of deeper submucosal invasion does not apply for NP-CRNs. In NP-CRNs, the difference in the size of lesions with superficial and deep submucosal invasion is not pronounced. LST-Gs with even-sized nodules have a low risk (<2%) of submucosal invasion, irrespective of size, whereas LST-Gs with mixed-sized nodules have a higher risk of submucosal invasion (7.1% for lesions <20 mm and 38% for lesions >30 mm), with the point of invasion usually located under the largest nodule. The LST-NGs, particularly those that have a thinner center (LST-NG with pseudodepression) also have a high risk of submucosal invasion: 12.5% for lesions less than 20 mm to 83.3% for lesions more than 30 mm. In such lesions the points of invasion are typically multifocal. Although depressed lesions are uncommon (1%–6% of NP-CRNs), their risks of submucosal invasion are the highest: the overall risks are reported to be 27% to 35.9% compared with 0.7% to 2.4% in the flat lesions.


In addition to the macroscopic classification, there are several other important clues to submucosal invasion in NP-CRN, including fold convergence, expansion appearance, and ulceration ( Box 3 ).



Box 3





  • Macroscopic signs:




    • Expansive appearance



    • Deep depression in surface



    • Irregular bottom of a depression



    • Fold convergence



    • Tumor size



    • Presence of white spots (chicken-skin appearance)



    • Redness



    • Firm consistency




  • NBI NICE type 3



  • Pit pattern type V invasive



  • Nonlifting sign positive a



a False positive can occur due to desmoplastic reaction, scarring from prior biopsies or incomplete EMR, India ink tattooing or chronic inflammatory disease.


Findings that suggest submucosal deep invasion


Microscopic characterization (optical diagnosis)


Optical diagnosis is a real-time, in vivo microscopic characterization of a lesion at the tissue level during endoscopy that is based on objective criteria and is reproducible. Objectivity based on standardized and reproducible criteria is important to bring the validity of the optical diagnosis to the same level as pathologic diagnosis. Both electronic and dye-based image-enhanced endoscopy techniques are conceptually similar to the application of the various stains in pathology and can delineate the neoplastic borders. They can enhance optical diagnosis and provide information on the depth of invasion.


In practice, we routinely use image-enhanced endoscopy to make an optical diagnosis. Following a detailed high-definition white light inspection of the lesion, we perform image-enhanced endoscopy using narrow band imaging (NBI) to systematically characterize the lesion color and mucosal surface and microvascular patterns. We apply the Narrow Band Imaging International Colorectal Endoscopic (NICE) classification to make an optical diagnosis (type 1, hyperplastic; type 2, adenomatous or superficial invasive carcinoma [<1000 μm]; or type 3, deep submucosal invasive cancer) ( Fig. 1 ). Lesions that are a good match with the criteria are considered to have high confidence. We spray diluted indigo carmine (0.2%) to confirm the diagnosis of a depressed lesion, which is characterized by dye pooling into the depressed area. The indigo carmine solution can also help delineate the borders of the lesion before and during resection. We do not routinely apply the Kudo classification, although it can be useful to confirm the optical diagnosis. We use the clinical classification: hyperplastic, adenoma, and deeply invasive, as proposed by Matsuda and colleagues.




Fig. 1


NICE classification.


Optical diagnosis is vital to the management of complex colorectal lesions. All of the lesions shown in this article were optically diagnosed before resection. Deep submucosal invasive lesions are generally not resected by endoscopy because their resections are associated with increased risks of complications, and they have a high risk of metastasis.


The nonlifting sign


The nonlifting sign, which is assessed during the submucosal injection, provides further opportunity to assess for the possibility of submucosal invasion. The nonlifting sign has shown a predictive positive value of 80%, negative predictive value of 96%, and an overall accuracy of 94.8%. It can be falsely positive because of submucosal fibrosis (secondary to prior biopsies, incomplete resection, or cauterization), desmoplastic reaction under the lesion, prior India ink tattooing, or presence of ulceration.




Resection techniques


Resection techniques to treat difficult colorectal lesions include the inject-and-cut endoscopic mucosal resection (EMR), EMR with specialized cap (EMR-C), EMR with band ligation (EMR-L), underwater EMR, endoscopic submucosal dissection (ESD), and specialized polypectomy techniques ( Box 4 ).



Box 4





  • Inject-and-cut EMR



  • EMR-C a



  • Underwater EMR



  • ESD



  • ESD-universal



  • Ligate and let go (for colonic lipomas)



  • EMR of rectal carcinoid using band ligation a



a Unsafe in the colon due to high risk of muscularis propria entrapment.


Advanced resection techniques


General Recommendations


Personnel


Personnel who are proficient in the use of the range of equipment and the intricacies of the technical procedure details, and who remain calm to manage complications are critical assets in performing advanced resections.


Equipment


We use high-definition adult colonoscopes with a water jet channel. We often use the therapeutic upper endoscopes when the lesion is located in the left colon. Pediatric colonoscopes featuring a smaller diameter may be useful to retroflex in the right colon to manage lesions extending over folds. Distal attachments can be helpful to improve visualization behind folds and stabilize the endoscope tip. We use CO 2 insufflation because it has been shown to improve patient comfort during and after the procedure, and it decreases the risk of tension pneumoperitoneum if a perforation were to occur. The accessories that we routinely use are shown in Box 5 .



Box 5




  • 1.

    High-definition endoscope with water jet




    • Colonoscope



    • Pediatric colonoscope



    • Therapeutic upper endoscope



  • 2.

    Carbon dioxide regulator


  • 3.

    Water irrigator with pedal activator


  • 4.

    Distal attachments compatible with selected endoscope


  • 5.

    Indigo carmine in a 60-mL syringe


  • 6.

    Injection needle (25 gauge)


  • 7.

    Electrosurgical generator


  • 8.

    Injectant (10-mL syringes of indigo carmine and saline; tattoo agent)


  • 9.

    Stiff snares (small and large)


  • 10.

    ESD knife (dual knife)


  • 11.

    Biopsy forceps (standard and jumbo cold forceps)


  • 12.

    Endoscopic clips (if using resolution, we take the sheath off)


  • 13.

    Endoscopic loop


  • 14.

    Band ligator


  • 15.

    Argon plasma coagulator with straight catheter


  • 16.

    Coagulation forceps (Coagrasper, hot biopsy forceps)


  • 17.

    Retrieval net


  • 18.

    Multichannel suction trap


  • 19.

    Pins and Styrofoam



Standard equipment and accessories used for advanced endoscopic resection


Choice of sedation


The ideal sedation is conscious (moderate sedation). Deep sedation with propofol may result in labored breathing, which makes the colon move significantly and interferes with the EMR. Furthermore, patient repositioning, which is often required in order to optimize the procedure, may be difficult in obese patients.


Injection


Injection solutions


Saline is commonly used worldwide. Glyceol, which is composed of glycerin, fructose, and NaCl solution, is commonly used in Japan. Hyaluronic acid solutions have shown longer duration of mucosal elevation compared with saline, independently of the concentration used (0.4%, 0.2%, or 0.13%). However, it does not cause a significantly higher elevation of the mucosa compared with saline. Other solutions have been described in search of a solution that stays longer, but none is commonly used.


Injection techniques


We use a dynamic submucosal injection technique ( Fig. 2 ) that is designed to create a generous bulge under the lesion. In this technique, after puncturing the mucosa and inserting the needle into the submucosa, a small amount of saline is injected to confirm insertion into the submucosal layer, followed by rapid large-volume injection. Unlike the variceal injection technique, in which the needle is kept stationary during the injection (static injection technique), dynamic submucosal injection involves moving the needle within the submucosa by slowly deflecting the tip of the endoscope or gently pulling the catheter back to create the desired mound of submucosal fluid cushion with injection. At the same time, air is suctioned out of the lumen. In essence, the submucosal bulge is sculpted.




Fig. 2


The dynamic injection technique. The dotted arrow shows the planned path of the needle that was to be followed during injection ( A ). Diluted indigo carmine solution in saline was injected rapidly while lifting the tip of the endoscope and suctioning the lumen ( B ). Further injection ( C ). After 8 to 10 mL of injection, there was a large submucosal cushion ( D ). A stiff 10-mm snare was used to capture the lesion and surrounding normal tissue ( E ). After resection ( F ).


It is important to appreciate the difference between the dynamic and static injection techniques. In the static technique, after inserting the needle into the submucosa, the needle is kept stationary until an adequate amount of fluid is slowly infused. In this technique the lumen is maintained insufflated to allow visualization of the lesion during injection. A common disappointment after the static injection technique has been inadequate thickness of the submucosal cushion, which is unsatisfactory for successful resection, because the injected saline spreads thinly throughout the area rather than collecting as a mound under the lesion.


EMR


The inject-and-cut EMR


The inject-and-cut EMR is a simple technique that is widely used for removal of large flat or sessile lesions. Lesions larger than 20 mm cannot be removed in a single piece (en bloc resection), and in such cases piecemeal resection is required.


We use a stiff snare for EMR after dynamic submucosal injection. If an LST-G mixed lesion with a large nodule is encountered, it is important to resect the large nodule in a single piece and submit it in a separate bottle of formalin after fixing it because of the likelihood of advanced features or invasive carcinoma underneath such a lesion. Our preference is to resect LST-NGs en bloc if they are less than 20 mm.


After capturing the lesion with a snare, the lumen is insufflated with air to stretch the wall, and the snare is lifted up while the snare is slightly loosened to release any entrapped muscularis propria. The lesion is then strangled and transected using blended current: 35 W in the left and 40 W in the right side of the colon. In large lesions requiring piecemeal resection, successive resections should be performed using the free resection margin from prior resection as an anchor point. Additional submucosal injections can be performed through the already-visible submucosa to create a cushion if necessary for safe resection. It is important to keep the snare parallel to the wall during piecemeal resection to avoid entrapping muscle when a snare is deployed at an angle.


Prevention of recurrence using argon plasma coagulation


A major drawback of piecemeal resection is the risk of leaving residual tissue at the end of resection, which can ensure recurrence in 100% of cases. We resect all visible neoplastic tissue. Application of argon plasma coagulation (APC) to the borders and bridges of the resected area may burn microscopic residual tissue to reduce the risk of recurrence.


EMR-C


EMR-C with a prepositioned snare in the colon has been regarded as unsafe because of the theoretic risk of entrapment of thin colon wall during suction of the lesion into the cap resulting in perforation, although this technique is widely used in the resection of lesions of the rectum where the wall is thick.


Underwater EMR


Binmoeller and colleagues observed that the muscularis propria of the colon and rectum that are filled with water stay circular during endoscopic ultrasonography. Thus, he proposed to use water immersion to eliminate the need for submucosal injection during mucosal resection. To perform this technique once the lesion is identified, the air is suctioned and 500 mL to 1 L of water are infused until complete filling of the lumen is achieved. Once underwater, the margins of the lesion are marked using APC. The resection is performed using a 15-mm duckbill snare with blended current. To maximize tissue capture a torque-and-crimp technique is used. APC can be delivered underwater as well. Note that the lesions are resected in piecemeal fashion.


ESD


En bloc resection is recommended for lesions that are deemed to have high risk of harboring high-grade dysplasia or superficial submucosal invasion, or lesions that may be difficult to remove using the other available techniques. The indications for ESD recommended by the Japan Colorectal ESD Standardization Implementation Working Group include lesions difficult to remove en bloc (including LST-NG, especially of the pseudodepressed type; lesions showing a Vi pit pattern; or lesions 0–I with suspicion of adenocarcinoma); lesions with underlying fibrosis; sporadic localized lesions in ulcerative colitis; or local residual lesions after prior EMR ( Box 6 ).


Sep 6, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Advanced Endoscopic Resection of Colorectal Lesions

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