Does multiple myeloma become more radioresistant post transplant?

Anecdotally, I had a recent myeloma patient who developed progressive chest wall disease after ASCT and numerous prior rounds of therapy. I gave him 8 Gy in one fraction to two chest wall sites; one had a partial response before progressing months later, the second site progressed through RT with no response at all. Second time around, I gave both 30 in 10 fractions with the expected response. In most other situations, I have seen very good responses with 8 Gy x 1, consistent with this randomize...

Not that I've heard or seen, but would love to hear more about a case you may have had where RT didn't work well for a lesion in someone who had undergone ASCT for MM. I will say that I do think ASCT with high-dose melphalan works better systemically against extramedullary disease (EMD) than many of our novel therapies, so I wouldn't recommend deferring ASCT purely because of a risk of making EMD harder to treat with RT.