Hi SP and welcome.
I had CK over 9 years ago. Edema of the tumor can occur after any radiation treatment. The goal in prescribing any form of anti-inflammatory post radiation to help prevent the tumor from swelling too much. I was prescribed short term course of steriods after my radiation to prevent the tumor from swelling on my hearing/balance nerve, thus, potentially causing the tumor from pressing too much and blowing out my hearing.
For me, after speaking to my dad who was a pharmacist, I weighed out risks versus benefits. For the short term use that I was prescribed, the benefits outweighed the risks.
Bottom line, it's personal preference and yet, the treating teams have experience under their belts to know what may or may not work. OTC anti-inflammatories may be worth checking as well.
I hope this helps... and again, welcome.
Phyl