Esophageal Cancer Support Group
Esophageal cancer is malignancy of the esophagus. There are various subtypes. Esophageal tumors usually lead to dysphagia (difficulty swallowing), pain and other symptoms, and is diagnosed with biopsy. Small and localized tumors are treated with surgery, and advanced tumors are treated with chemotherapy, radiotherapy or combinations.

Believe me, I understand your fears. My wife and I felt the same. However, in my case, there was no reasonable alternative. As Pat once wrote (paraphrased, of course): it's not a matter of being brave. It just has to be done. I found that point very insightful.
Yes, the radiation/chemo can make you nauseated. There are some very good meds for this. I remember not taking my nausea meds at the proper time before a radiation treatment once. I took the pill right before the treatment. I will not ever forget the next 45 minutes before the med kicked in. It might be good to learn from my mistake.
One more thing: While it may be different for you husband, even at the worst of the nausea, I rarely actually vomited. The nausea could be intense. I learned to read all the info that came with ALL my meds. I "religiously" followed the med instructions.
You'll have to learn to trust your docs, but verify (per Ronald Reagan).
This brings us back to "Learn All You can"!!!!!!!!!!!!!!" It is still the best bet against this beast.
It'll make a difference.
All the best,
Fred