Carcinoma of the duodenum.

Ewing (1931) states that the incidence of malignant tumours of the small intestine is 3% of neoplasms of the gastrointestinal tract. Shallow, Eger, and Carty (1944) reported the incidence of primary carcinoma of the duodenum in a study of 350,286 necropsies as 003%; the duodenum is affected in 45.6% of cases of small intestinal neoplasms. In this series care was taken to exclude undifferentiated neoplasms of the ampulla of Vater and of the biliary and pancreatic systems, all of which are mixed with the figures for the incidence of duodenal carcinoma throughout its history. Ficarra and Marshall (1945) state that in order of frequency the duodenum is the commonest site for carcinoma of the small bowel if carcinoma of the ampullary region is included, and hence special attention must be paid to the pathology to establish the primary site and obtain true figures for its incidence. Spinazzola and Gillesby (1963) give the distribution of duodenal neoplasms for the first part of the supraampullary region as 18-23%, for the second part as 50-65%, and for the third part as 15-200%. In their review of the tumour registry at the Veterans Administration Hospital, Hines, Illinois, from 1931 to 1960 inclusive, they found 31 cases of small bowel neoplasm. Of these, 390% (12 cases) were in the duodenum and only authenticated cases were included; eight of the 12 were adenocarcinomas (three carcinoid and one leiomyosarcoma). Most of the tumours were of the polypoid or ulcerating type. The incidence in males is approximately twice that in females, the average time between the onset of symptoms and diagnosis six months (Shallow, Eger, and Carty, 1945) to 11 months (Dixon, Lichtman, and Weber, 1946). These neoplasms occur most frequently in the fifth and sixth decades.