Dear Eric,
I'm so sorry your wife is not "responding" to you. I think it's a good idea for you to talk to someone else since she's not there for you at the moment. Hopefully she'll come back around.
I don't know if this will help, but my husband has been cancer free for 5 year's now. The first couple year's out it seemed like any bump, lump or whatever would absolutely freak him out (which is totally understandable). Seeing him so scared/freaked out would make me try to be the calming influence over him. I would talk to him soothlingly and try to reassure him that a bump/lump showing up overnight would not likely be cancer. I tried to be the "voice of reason" if you will. It did seem to help.
Another thought...maybe she's tired of talking about cancer all the time. For a caregiver it's very emotionally draining and maybe she just needs a little break to regenerate herself. I wish you both all the best.
Shelley