What are the applications of EMR and ESD?
These techniques provide definite therapy for benign lesions, premalignant lesions, and early malignancies (Tis and T1N0M0). EUS and Kudo’s mucosal pit pattern analysis may be used to assess the tumor-node-metastasis (TNM) staging and invasiveness and removability of the lesion. Lesions in the mucosa, lesions with minimal submucosal invasion up to 1000 μm with tumor-free margins, and lesions that are well differentiated and moderately without lymphovascular involvement can be considered cured. The rationale for EMR and ESD in early malignancy is that there is very low probability for lymph node involvement in Tis and T1 stage. Furthermore, when accessible, EUS can determine the status of Tis and T1 with 91% to 94% accuracy. A few examples include adenocarcinoma of the esophagus and colon, flat polyps, gastric nodules, and duodenal adenomas.
Stage of Cancer and Lymph Node Involvement Status
Rice TW, Zuccaro G Jr, Adelstein DJ, et al. Esophageal carcinoma: depth of tumor invasion is predictive of regional lymph node status. Ann Thorac Surg 1998; 65: 787-92.
How is EMR performed?
Various commercially available EMR kits can be used. The EMR cap is made of clear plastic that can be soft or hard and straight or oblique in various sizes up to 18 mm. Larger caps are soft to allow easier passage into the GI tract. The oblique caps are helpful in the esophagus and straight caps are helpful in the stomach. The target lesion is raised with submucosal injection to form a cushion. An EMR cap of desired size is affixed to the tip of the endoscope. The electrocautery snare is opened and positioned on the distal internal circumferential ridge of the cap. The scope is advanced and placed over the lesion. Suction is applied to retract the lesion into the cap. Once the lesion is well positioned in the cap, the snare is closed and the lesion is captured with the snare. The suction is released. The lesion is then resected like a polyp. The lesion can be retrieved in the cap using suction. In addition to the previously discussed EMR cap technique, there are several variations on EMR techniques, such as “inject, lift, and cut,” and a newer banding device for mucosectomy can be used. (See the website at the end of the chapter for a link about how to perform EMR.)
How is ESD performed?
The lesion is located and raised with submucosal injections. The borders of the lesion are defined using narrow band imaging or adding a dye to the suface of the lesion (chromoendoscopy). The needle knife is passed through the instrument channel of the scope and a circumferential submucosal cut is first made using fine movements and maneuvers. Subsequently the base of the lesion is dissected with multiple cuts. Multiple submucosal injections are needed as the submucosal cushion tends to dissipate with time. One modified needle knife (ERBE Hybrid knife) allows injection and cutting using the same needle. Once the lesion is freed from the base, it can be retrieved with a Roth net or a spider net. The specimen is immediately mounted on polystyrene foam with pins and oriented for pathologic examination. In addition to the previously discussed technique, there are other variations to the ESD such as magnetic anchor–guided ESD. (See the website at the end of the chapter for a link about how to perform ESD.)
What are the differences and limitations of the EMR and ESD?
The EMR is limited by the largest suction cap size of 18 mm to accommodate the narrow passages in the GI tract. This is can be overcome by ESD. EMR and ESD cannot be performed in areas such as the distal small bowel that are not accessible by traditional endoscopes. These procedures are technically difficult, time consuming, and labor intensive, and specialized training is needed.
What are the complications of EMR and ESD?
The major complications include bleeding (average 10% in various series) and perforation (4% to 10% for ESD) and (0.3% to 0.5% rate for EMR). The table lists gastric ESD complications. Most bleeding can be handled endoscopically using coagulation graspers and endoscopic clips without surgery. Most perforations can be handled endoscopically using endoscopic clips and loops without surgery. describes nonsurgical treatment of ESD perforations. In certain instances, especially when the perforation is large, surgical repair is needed. In our own series for colorectal ESD using the new modified needle knives, bleeding rate was 1.8% and perforation rate was 1.8% (n = 220). Other complications include stricture (esophageal or pyloric) and infections.
Endoscopic Dissection. Endoscopy. 2006;38 (10):980-1028 (entire issue).
|Study Author||n||Lesion Size mm||Enbloc Rate %||Bleed %||Perforation %|
ESD, Endoscopic submucosal dissection.
What are some investigational applications of EMR and ESD?
These techniques used in combination with EUS aid in accessing lesions outside of the GI tract such as mediastinal lymph nodes and intraabdominal organs such as the gall bladder. Once the technique to create and then close an endoscopic transluminal opening (perforation) is mastered. Therefore EMR and ESD facilitate the development of other techniques such as natural orifice translumenal endoscopic surgery and mediastinoscopy. Full-thickness endoscopic resection has been performed using modified needle knives for the therapy of gastrointestinal stromal tumors (GISTs).
What are some investigational applications of advanced EUS?
• EUS-guided pancreatic necrosectomy and drains with large-bore plastic or metal stents
• EUS-guided antitumor therapy
• EUS-guided nonpapillary pancreatic and bile duct drainage
What is the role of EUS-guided FNA biopsy in tissue sampling and sampling of nodes?
EUS-FNA has been shown to aid in the diagnosis of primary lesions within or close to the GI tract such as rectal, esophageal, pancreatic, and lung cancers. The EUS-FNA of lymph nodes has overall sensitivity of 84%, specificity of 92%, positive predictive value of 88%, and negative predictive value of 89%. The sensitivity and specificity vary with the type and location of lesion being evaluated. The sensitivity and specificity of EUS-FNA is higher for lesions such as pancreatic neuroendocrine tumors and pancreatic cancer, and lower for submucosal lesions such as GISTs. The main utility of EUS-FNA is in nodal staging of these lesions, allowing not only imaging of lymph nodes but also providing samples of these nodes