It generally responds to treatment with prolonged remissions and it tends to not be either subtly disabling or quickly disabling so it's got that going for it with the FAA. But it's a rare disease and you probably want to get the best hematology-oncology service you can find to deal with it, not the local one or two oncologist medium size city's office. Places like these:

https://health.usnews.com/best-hospitals/rankings/cancer

https://www.mespoir.com/usa/all/hematology/all/hospitals

With treatment by the best specialists and a good result long term remissions are very likely, and that may pass muster with the FAA with good follow-up. But yeah, AMAS or similar is the way to go once you are in remission and the best oncology and/or hematology services recommendations will have more clout with the FAA medical folks than your local MD. They are worth the extra effort all around.

Best of luck to you.