@carolee888 Perhaps you can ask your current doctor if he/she has any input. Hematologist oncologists seem to inhabit a small corner in the cancer world, and your team may have some suggestions.

I looked up Healthgrades, putting in Las Vegas, and here are the results: https://www.healthgrades.com/find-a-doctor/nevada/best-doctors-for-myeloma-in-las-vegas
Also, there is a school of medicine associated with University of Nevada Las Vegas. Good for you for thinking ahead!
Ginger

In my experience, doctors who treat conditions that are a tad uncommon tend to know others throughout the country also treating it. (One good argument for those conferences and continuing education programs they attended is keeping up to date with other specialists.) So get referrals locally if you can. If someone sounds good, your doctor can help ease you into that doctor's practice by sharing your med records before you make the move. You can always change doctors later but it's reassuring to have doctor's already familiar with any special needs before arrival. And makes moving a lot less stressful.