Rare resected eight cases of duodenal adenocarcinomas

•Duodenal cancer used to be rare disease and, however, we have increasingly experienced surgical intervention for duodenal cancers because it might be due to development of duodenal endoscopic examination.•For early cancers, duodenal resection preserved surrounding organs such as a pancreas can be indicated, otherwise pancreaticoduodenectomy is necessary for advanced stage duodenal cancer located up to 3rd portion of duodenum.•Patient prognosis can be expected by the novel adjuvant chemotherapy after curative duodenectomy.