DW,
I hope you'll get more responses to your question from those with personal experience.
From what I've read anyway, hair regrowth after WBR is variable from person to person.
But, I don't recall anyone saying that their hair didn't regrow in some form or another. Only that, for some, there were
areas of no regrowth. And that was frustrating in itself for them.
My hair loss in spots, from focalized radiation, did completely regrow.
Unless you look great bald and/or it 'fits' with your personality, hair is a VERY big deal. I've so far avoided tx's that cause hair loss since mets dx. Once was enough to deal with... in my opinion
)
Best wishes to you,
pattyz