You're likely SOL. It just speeds up the natural process. If you're predisposed it's going to happen inevitably.. I suggest embracing it when it comes time. Don't hold onto a smidgen of hair on the top and sides. (Think about how hot most women think Jason Statham is..)
What I find interesting is when I take a steroid other than test that converts to DHT (anadrol, masteron, anavar, winstrol, etc.).. I will have thinnng hair! When I'm on TRT though.. it's hardly the case, and from my understanding Test does convert to it. It's almost the opposite too, my head hair will grow in very thick, and my beard will be very full.
I'm not sure how it works, or if I'm using the terms correctly, but regardless, if my TRT was causing hair loss I would shave it all off and keep it at minimal length when it did grow back.