Sounds like that is a good question specific to your concerns about having had a brain tumor to ask your doctor just to be sure. I'd like to hear what you learn.

Not related specifically to a brain tumor, some people may have a difficult time acclimating to high altitude living. There are many articles online. Here's one blog post
- How to Adjust to Altitude Changes (and Not Get Sick) https://www.inaraft.com/blog/how-to-adjust-to-altitude-changes-and-not-get-sick/