Any ideas why a person with esophageal cancer will have a feeding tube inserted into the duodenum instead of the stomach?

Better tolerated. Two major reasons. First, the stomach is the preferred organ substitute for esophageal cancer surgery, and second, duodenal feedings are generally better tolerated, and are associated with less reflux.

Related Questions

Why do esophageal cancer patients have a feeding tube inserted into the duodenum instead of the stomach?

Surgery location. Short answer from a non-surgeon. The percutaneous endoscopic gastrostomy (peg) feeding tube may interfere with a potential esophageal surgery more than a percutaneous endoscopic jejunum (or duodenum) (pej) tube in the small bowel (after the stomach). This isn't always the case, but one reason.
To avoid stomach. When your esophagus is removed due to cancer (esophagectomy) in order to eat again, your stomach may be used to replace your esophagus (stomach conduit). Therefore you want to avoid any surgery that may compromise the use of the stomach as a conduit. Therefore a feeding tube would be placed in the small bowel or jejunum. This is called a "j" tube.