Is proximal duodenal adenocarcinoma (above the ampulla of vater) considered biologically similar to colon adenocarcinoma or gastric cancer?   

Does the precise location of duodenal cancer even matter given that treatment would be 5FU/platinum based. Also with the knowledge of impact of sidedness on the prognosis and treatment choices for colon cancer what would be the side assigned to duodenal cancer- Right sided? Has this been looked at?