Endoscopic ultrasound (EUS), as a preoperative procedure, has become an important modality in the asssessment of pancreatic, biliary and ampullary tumors, especially when they are small (<3cm).
Endoscopic ultrasonography provides the endosonographer the best of both worlds. Not only can one visualize structures endoscopically, but also one can see through the gut wall and better define the extent of disease and more effectively plan therapy. Linear array echoendoscopy produces a scanning plane, which is parallel to the the long axis of the endoscope. Hence, endosonography-guided fine needle aspiration biopsy (EUS FNA), endosonography-guided fine needle injection (EUS FNI), duplex endosonography, and endosonography -guided celiac plexus neurolysis (EUS CPN) can be performed. The role of linear array echoendoscopy in cancer staging and management will be critically reviewed.
Pancreatic cancer diagnosis and management has been enhanced with the application of endoscopic ultrasound. The close proximity of the pancreas to the stomach and duodenum permits detailed imaging with intraluminal ultrasonography and staging of pancreatic tumors. EUS directed fine needle aspiration and injection may be successfully employed with patients with pancreatic cancer. Expandable metal stents can palliate patients with obstruction of the pancreaticobiliary tract as well as the gastroduodenum. The efficacy of EUS in the management of pancreatic cancer is critically reviewed.
The most frequent primary cancers causing malignant obstructive jaundice were pancreatic cancer (57%), hilar biliary cancer (19% including metastatic disease), nonhilar biliary cancer (14%) and papillary cancer (10%). Endoscopic stenting has widely replaced palliative surgery for malignant biliary obstruction because of its lower risk and cost. Self-expandable metal stents are the preferred mode of palliation for hilar malignancies. Plastic stents have a major role in benign biliary strictures. Major complications and disadvantages associated with metallic stents include high cost, cholangitis. malposition, migration, unextractability, and breakage of the stents, pancreatitis and stent dysfunction. Dysfunction due to tumor ingrowth can be relieved by thermal methods (argon plasma coagulator therapy). We present a concise review of the efficacy of metallic stents for palliation of malignant strictures.
Metallic stents are effective in relieving colorectal obstruction in more than 80% of cases. Self expanding metallic stents allow for decompression of the proximal colon and preoperative bowel cleansing. Hence, emergent surgery for large bowel obstruction with its associated high morbidity and mortality might be avoided. Endoscopic laser photoablation and stent placement may successfully palliate inoperable colorectal cancer patients by maintaining luminal patency and avoiding the need for a colostomy. Major complications associated with metallic stents include pressure necrosis, perforation, bleeding and migration. The effectiveness of expandable metallic stents in obstructive colorectal carcinoma is critically reviewed. The authors present a concise review of the effectiveness of endoscopic laser photoablation and expandable metal stent placement.
Malignant dysphagia is a serious condition in which 70% of patients die within one year, regardless of the treatment received. It provokes a rapid deterioration of a patient's physical condition and a significant worsening of quality of life. The surgical treatment of dysphagia is frequently complicated with technical difficulties, and often the tumors cannot be excised because of extensive invasion into adjacent structures. Furthermore, many patients are considered inoperable due to advanced age, associated diseases and malnutrition. Laser photoablative therapy coupled with expandable metal stents restores luminal patency in more than 80% of patients allowing them to eat liquids and soft foods. The efficacy of laser photoablative therapy and expandable metal stents for the palliation esophageal carcinoma will be critically reviewed.
Precise tumor-staging is critical in the management of early esophageal caner. Endoscopic ultrasound (EUS) allows the endoscopist a view beyond the esophageal wall which opens the door to a variety of new gastroenterologic techniques. Endoscopic mucosal resection, laser photoablation and photodynamic therapy may be successfully employed in early esophageal cancer management. Combination radiation therapy and chemotherapy have shown better responses in advanced cancer. Expandable metallic stents may also provide palliation with inoperable esophageal cancer. The efficacy of EUS in the management of esophageal cancer is critically reviewed.
Enhanced endoscopic detection of small flat adenomas is becoming increasingly important as they have a reported 14 percent incidence of dysplasia when compared with 5% incidence in polypod adenomas of the same size. These lesions even when invasive do not show up against the translucent surrounding mucosa making endoscopic detection difficult. Dye spraying with indigo carmine makes their morphology clear, with well-circumscribed borders. Dye spraying and magnifying endoscopes can be used to observe pit patterns on the surface of the bowel. Combining dye spraying and high-resolution video endoscopy demonstrates well the colorectal epithelial surface. Scanning immersion video endoscopy visualizes the epithelial surface of the colorectal mucosa by high-resolution endoscopy after filling the lumen with water. Endoscopic ultrasound can be used to see if the lesion is intramucosal or not and assess the depth of invasion if malignancy is presented. Laser induced fluorescence spectroscopy has the potential to detect colonic dysplasia in vivo. Combining such technologies with conventional colonoscopy can help in the surveillance of large areas of colonic mucosa for the presence of dysplasia. Guided biopsy can replace random biopsy based on information provided at the time of colonoscopic examination.
Videoendoscopy has truly enlarged the scope of diagnostic and therapeutic gastroenterology. However, videoendoscopic examinations are limited to the mucosal surface. Endoscopic ultrasound allows the endoscopist a view beyond the intestinal wall which opens the door to a variety of new gastroenterologic techniques. The evaluation of plain images in combination with contrast-enhanced imags has been found to be helpful when applied to CT and MRI. A similar advantage may be found for endoscopic ultrasound (EUS) studies. The efficacy of EUS with and without contrast enhancement is critically reviewed.
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