Probably not. Despite thoughts that some breast disease can be oestrogen triggered, you have found quality of life after a long haul. Keep that thought in mind that you had a fight to get stable!!
I underwent the procedure that you are facing - there will probably be a gap between the surgery and the start of radiation to allow wound to heal and to give the body a break; the lump should be taken to histology even though it's seen on mammogram. Is there an option for mastectomy, so that you could continue with HRT? Was this discussed? I had a small area of 'sunburn' over the radiation site which was treated with steroid cream.
If you feel that is a option do ask to see the Surgeon again. We are told so often that we shouldn't use HRT if there is breast disease but I can't understand why we aren't offered bitateral mastectomy if HRT can be prescribed after. HRT can be a Life saver after all.
Do find out what you will be taking as an oestrogen inhibitor.
tamoxifen almost killed me as I became sensitive to smells, taste, had cold flushes
and as I hadn't felt ill during diagnosis and treatment, decided not to continue with it. Still here >wave<. There are other medications now I believe worth visiting a Pharmacist perhaps to discuss?
Let us know how you get on. Also, once the surgery and treatment is over, it might be worth you writing to the manufacturer of the product or getting the Surgeon to do so. I believe that without communication treatments won't evolve.