This is a interesting observation which may assist others who face the chemo regime where they won't lose all their hair, but it will just thin, as happened to me. I'll stick some tags on the post in the hope that it will be found by those who seek such information.
Back in the summer of 2011 when I was receiving chemotherapy treatment for lung cancer my hair thinned in that a lot of it fell out at the same time. I'd been warned this would happen but told I wouldn't go completely bald. As it was I don't think most people noticed any change.
It began to grow immediately, while I was still having chemo, and I faced quite a marked period of whispy bits sticking out amongst the long tresses and a distinct second layer which could be seen clearly as it lengthened. It's all more or less the same length now.
What I've noticed in the past couple of months is that a lot is falling out again at the same time, leaving it quite thin again. I can only conclude that all the hair that started growing after the first falling out, has now reached the end of its natural life and stopped growing. Yes, I can see small whispy bits of new growth as before so it will all come back. I just find the whole thing fascinating and felt I should note it for posterity, if nothing else.
I still have that chemo curl by the way because the hair that didn't fall out during chemo is still believe it or not mainly in place. That leads me to conclude that the new hair has had a shorter life than the old hair which is still there and falls out on average every five years. This new stuff has only managed four, but given the state of my body when it started out I guess that's not surprising.
Oh one more thing, another check-up is looming at the start of next month. I have no reason to think that anything suspicious will be found and I'm looking forward to saying a fond farewell to the consultant.