Early adenocarcinomas in the small intestine are a rare entity. Most adenocarcinomas in the small intestine are diagnosed at a more advanced stage. After surgical resection, only 3 - 10 % are found in stage T1 and 0 - 3 % in stage Tis (high-grade intraepithelial neoplasia), resulting in an overall 3 - 13 % rate of early-stage small-intestinal adenocarcinomas. The diagnosis of early small-intestinal carcinoma by endoscopy is still very rare, although it will probably improve with the development of new endoscopic techniques. At present there have been only two studies and a few case reports on the treatment of early duodenal carcinoma by endoscopic resection. No major complications such as massive bleeding or perforation occurred in the studies and case reports, which show that endoscopic resection is a safe and effective treatment for early duodenal cancers that have not invaded the submucosa. Endoscopic resection can be carried out with reduced costs and lower morbidity and mortality rates in comparison with surgery.