I'm really surprised someone at U Mass Medical said she shouldn't go to Dana Farber for a second opinion. Until now, I've heard nothing but really good things about U Mass Medical.
What your sister has sounds like a PEG tube (and , if so, actually she didn't swallow the tube, she swallowed an endoscope with a light at the end that they would have used, when it got to the stomach to locate where they should cut to insert the tube. She was probably semi-conscious for this and it isn't fun, I can see why she might have thought she swallowed the tube itself). If she hasn't done so (but I have a hard time believing they wouldn't do this at U Mass Medical), she should meet with a nutritionist about using the tube and what sort of food to pour down it. Her insurance may cover prescription tube food, such as Jevity 2.0, which has more fiber (which will help her stay regular) and if so a hospital nutritionist can get that ball rolling.
I had some extra cushioning so I lost about 65 pounds altogether and about 40 of that I needed to lose and some of that was before the chemo and radiation and some was after. I think I lost about 20-25 pounds during chemo/rad. Since your sister has no cushioning, once she starts treatment she needs to be SURE she gets an adequate amount of calories down (either by swallowing or the tube) right from the start. The nutritionsit may know of some higher calorie stuff she can mix in with ehr regular tube food if calories really become an issue. Losing too much weight will interfere with her healing so it's really important.
Nelie