Abstract
Most malignant tumors in the upper digestive tract, as well as their nonmalignant precursors, are epithelial (carcinomas); they develop either in the squamous epithelium of the esophagus (squamous-cell carcinoma) or in the glandular mucosa in the stomach and in the metaplastic epithelium of Barrett’s esophagus (adenocarcinoma). Other primitive tumors include granular-cell tumors, lymphomas, melanoma, endocrine tumors, and leiomyomas. In addition, metastases from breast or lung cancer occur in the esophagus and stomach. Grouping esophageal and gastric tumors under a single heading is justified from a diagnostic point of view - esophageal or gastric tumors may be revealed by similar symptoms (dysphagia and restricted food intake), and both areas are systematically explored during upper gastrointestinal endoscopy. At the esophagogastric junction, precise classification of an adenocarcinoma as being situated in either the esophagus or in the stomach is often impossible; this is why tumors are classified using three distinct sites - the esophagus; the esophagogastric junction and cardia; and the noncardial stomach. Gastric cancer is thus divided into two areas - cardial and noncardial. In addition, the same endoscopic procedures of destruction or resection are used for small neoplastic lesions in both the esophagus and the stomach, and stent treatment for palliation of obstructions is now carried out in the esophagus, at the esophagogastric junction, and at the gastric outlet. On the other hand, the biology of tumors and their types of progression differ in the multilayered squamous epithelium and in the glandular epithelium, and this directly affects endotherapy techniques. With squamous neoplasia, the risk of metastases to lymph nodes, which is nil for intraepithelial neoplasia, increases dramatically along with the depth of invasion, reaching around 45 % when invasion of the submucosa reaches the lower third. With glandular neoplasia, the risk of metastatic lymph nodes is not nil for intramucosal neoplasia, but it is small; progression and depth of invasion into the submucosa are less dramatic than in the esophageal mucosa. This distinction between the two categories of tumor also applies to advanced cancer, and the options for surgery, radiotherapy, and chemotherapy differ. Since the last annual review of the literature [ 1 ] in this journal, trends in published reports confirm that two distinct directions are being followed in research on endotherapy for esophagogastric tumors: endoscopic mucosal resection (EMR) with curative intent for small tumors, and palliative stent treatment for neoplastic strictures.