Andrew:
I am the one who posted about the Peg Belt with Kate who responded to you earlier.
A couple things:

I know this situation stinks as my father in law, wife, and I have been living with this for about 11 months now. He has esophageal and gastric cancer. I did not directly experience the effects but I saw my father in law go through things so I experienced them very closely, second-hand.
His doctor basically told him the same thing as you. I know that after he started to get his treatments he needed the tube to keep his nutrition because it either hurt him to eat or he could not keep food down. I know people probably have different reactions to the chemo and radiation so please get more comments from folks on this site.
In the event you decide to go ahead with the feeding tube, the device my father in law designed may assist you as it did him with daily activities.
As DavidCPA pointed out our website is still in the process of getting pictures and being updated for the belt.
My father in law has since had the tube removed. I do feel his belt helped him stay active during the time that he had the tube in so if you are contemplating having the tube inserted and you plan on remaining active I would recommend the belt as an alternative again, from my father in law's experience.

Sorry so long winded......I wish you the best.