still tired on oxygen, i lose breath taking steps. can this improve or is this how people die?

Talk to your medical team.

Part of the tiredness could be that your body is still recovering from the trauma of your treatments. It took me months after I finished chemo and radiation until I stopped needing daily naps.

We don't know how your treatment are going. There may still be some further improvement if they have got some control over your cancer.

Hopefully you will be around for a good while yet and regain some quality of life.

Do you have COPD or CHF ? Neither of these are good. I worked in an assisted living and once the oxygen doesn't help any longer, well, what else is there? My mother is in the same boat. My mother in law was in the same boat. It happens. Just follow your doctors instructions.

Ask professionals!!

Hopefully there are a few here, but don't trust the general answer of the community.

You might also call other treatment centers and hospitals and see what they think.