Treatment while on ventilator?

My wife has been in the ICU on the ventilator for the past 2 and a half months. She has metastasis breast cancer to her lungs which had made it very stiff for her to breathe.  It is stage IV. The doctors doesn't think she will be able to get off the ventilator and has long as she is on it, chemo is not an option for her.  They are talking about how to make her remaining  days comfortable by give her pains med s and keeping are sedated.  She is 31 years old, strong, and occasionally complains about pain in her chest.  She is not on her last days as she says so herself and we see it.  She has weakened quite a bit as she is bed ridden, but her will is there and her mind is still sharp and strong.  But it seems the doctors have written her off as there isn't much they can do but just give her pain meds. So my question is, is there any kind of treatment possible for a metastasis breast cancer to the lungs while the patient is on the ventilator?