EPIDEMIOLOGY AND NATURAL HISTORY OF DUODENAL ADENOMAS AND ADENOCARCINOMAS

Abstract

Duodenal adenomas and carcinomas are clinically and histologically divided into ampullary and non-ampullary tumors. Non-ampullary tumors are classified into intestinal or stomach type based on the mucin phenotype. The intestinal type can occur anywhere in the duodenum, but the gastric type is more common in the proximal duodenum (oral side of papilla of Vater), suggesting a high degree of malignancy. Due to the higher rate and severity of complications, endoscopic resection for superficial non-ampullary duodenal tumors was not actively performed in Japan for a long time. However, the development of a new treatment method enables us to perform endoscopic resection more safely. On the other hand, some cases of adenoma were observed without resection. From the cases with long follow-up periods, the carcinogenesis rate was not so high. The treatment strategy should be decided taking into consideration potential complications, risk of carcinogenesis, the patientʼs condition, and prognosis. With appropriate evaluation of lesions based on understanding the characteristics and natural history of duodenal adenomas and adenocarcinomas, proper treatment strategies should be selected.