I have had in the past (2012) what I consider to be quite terrible side effects from ADT with LHRHa (Eligard similar to Lupron). So recently when I needed to start short-term ADT as adjuvant to pelvic lymph node radiation (IMRT with boost to nodes) I chose to try Estradiol patches. Now 7 weeks in and I have learned the following:
1) Estradiol can effectively lower testosterone by depressing GnRH but it is a gradual process requiring about a month to reach castrate levels.
2) The side effects profile is unbelievably better with estradiol! Zero hot flashes. No weight gain (nor loss). Good energy and eagerness to exercise that I haven't had in years. No fatigue (until the RT started producing a little). And no mental fogginess evident.
3) There is much variation in the delivery of supposedly equivalent brands of estradiol patches. I was using 4 patches at a time and changing one daily on a rotating basis (per PATCH trial findings). These are supposed to deliver 0.10 mg/24 hours each and are semi-weekly patches (4 day). I have used 3 different brands due to supply and insurance issues.
The first patches were generic Medicare approved and dropped my testosterone from over 350 to 90 within 2 weeks. When they ran out I had to order some from a (legitimate) Canadian Pharmacy and got Sandoz Estradiol Derm 100. These are very large and un-elegant patches that don't stick well but raised my E2 levels three times higher! Then I went back on another US product: Tamneal DOTTI estradiol transdermal. These are small and adhere well, but my E2 levels dropped by 2/3 on them. So the dosage delivery needs to be titrated and rechecked until stable. If I had to start over I would use Estradiol transdermal gel instead on a daily basis.
4) Because the last patches were not delivering the Estradiol adequately and my radiation was well underway, I decided to punt: To take a shot of degareliz (Firmagon) which drops T levels very rapidly. I feared my old ADT problems would re-emerge but delightfully they did not! With the Estradiol on board I have had no re-emergence of adverse or unpleasant ADT symptoms.
5) When I started the patches I experienced the start of some breast tenderness and glandular swelling within 3 days. So I started the Tamoxifen (I had at the ready) 10mg once daily. Within 24 hours 90% of the breast symptoms resolved and have remained steady (very mild).