This is the first time here I have heard if this particular cancer, and can offer no insights. But being about what I suspect is a similar age to you, I have had squamous cell carcinomas on my scalp recently, some of them quite large, which were surgically removed and healed back in by secondary intent. Scalp SCC is usually a function of solar radiation, and my hair thinned early in my life, leaving me with a scalp that the sun had easy access to, especially since I spent many days sitting on a surfboard out in the sun when I was a young man.
It seems curious that they are going to remove it and free flap tissue to it, then radiate it. You would think the excision would remove it all. This must be more aggressive than SCC. Good luck with this, please come back and let us know how things go. B