Estradiol levels with AI
Since a recent study (May 2022) found that estradiol was lowered similarly whether the AI (exemastane) was taken daily or every other day, does anyone know what is the aimed at level of estradiol when taking AI ? And can they confirm a blood test would allow one to know this?
Thanks!
Interested in more discussions like this? Go to the Breast Cancer Support Group.
Thank you so much for sharing! I meet with oncologist next week and will ask as I believe national oncology conference was held this week. I am very anxious about quality of life while taking AI's. I'm 57 yrs and just starting on this journey.
If you can, do post what you learn! My surgeon/oncologist was away at a conference this week, maybe the same one!
Thank you.
If you read this carefully, you will notice this:
"The authors found that both adverse events and menopausal symptoms were similar in all arms."
I have been speculating about this for years and often on this forum.
The Femara insert says that 20% of the normal dose reduces estradiol below detectabel levels. Eight years ago I asked my oncologist about taking it alternate days and was given permission (I stayed with full dose).
So logically, if estradiol is reduced enough to be effective, side effects would be the same regardless of the dose, right? Because side effects are from estrogen suppression. Including menopause-like effects and many others.
I hope people read that study carefully because it confirms side effects were the same with the lower dose. I don't see how it makes any difference what the dose is, if the drug suppresses estrogen at any level of dose.
@windyshores “ So logically, if estradiol is reduced enough to be effective, side effects would be the same regardless of the dose, right? Because side effects are from estrogen suppression. Including menopause-like effects and many others.”
I’m thinking about this statement …. If I took say Ibuprofen & and took 8 all at once vs spreading over a 24 hour period the side effects would be different. There is something about taking more (80%) & less (20%) that the side effect is the same is not clear. I might be missing something. Maybe time release into our bodies plays a role. Is full dose more effective against estrogen than the 20%.?
I am not advocating for or against AIs as it is purely personal as all our bodies are so very different. Side effects get discussed a lot bit I’m not hearing do much about effectiveness. My doctor could not tell me if Anastrozole was actually working .. said they take it for granted. That not a very scientific or medical studied answer.
@sequioa you can't really compare dosing of ibuprofen and aromatase inhibitors. I don't know if you saw the study elsewhere in this forum that showed alternate days to be as effective as daily but side effects were the same. I do wonder if dosing will change at some point (to half of what it is now). The Femara studies showed effectiveness with 20% but doubt that will become the practice.
Docs rely on standards of care established by studies. They should refer you to studies, I think, but blood tests aren't very useful to determine effectiveness.
@windyshores I wasn’t actually comparing ibuprofen & AIs as they are two different meds. Poor example I guess. My point was if you took any med all at once vs. taking as prescribed you’d probably have side effects. Again I’m not stating this well. Sorry. Is blood tests which aren’t very useful how they -researchers & doctors - actually determine effectiveness. I’m interested but not for sure if there is an answer. I know they’ve done studies and I’m glad that there is medication that helps breast cancer patients but one size - I don’t believe - fits all. How does an oncologist decide which AI to prescribe to a patient. Maybe the last sales person that gave him the last info on their drug at their pharmaceutical company. I don’t want to drag this out further but these are some of the areas of my concern. I’ll drop this now. Thank you @windyshores for the input.
But the point of the study was in fact to examine whether a lower dose would be as effective in lowering circulating estradiol because the authors suggest a lower dose would presumedly result in lower toxicity (and therefore fewer nasty side effects). The lower dose was just as effective apparently but a longer follow up period needed to examine tolerability (SE issue). Personally I’d choose a lower dose if equally effective and I like that they point out that researchers are now questioning the premise that higher doses in general are necessarily better. (Big pharma won’t be on board with this!) Thanks for yr input!
Given the relatively long half-life of anastrozole, and my low BMI, I am taking it every other day. My oncologist says that taking it as I am is better than not taking it at all. He has written in his medical notes that I am taking it on alternative days "by preference." I find that the side effects are somewhat reduced but estrogen deprivation still takes its toll. An official study on dosage for all AIs would be great. There was a small Italian study on low-dose tamoxifen that found that 5mg was as good as 20mg for prevention and reducing adverse SEs.
Again, the study above says side effects were the same for all doses tested. Not sure how this relates to the other comment in the study about toxicity.
The insert that comes with Femara states that 20% of the dose reduced estradiol below detectable levels. My doc okayed every other day.
The question would seem to be, is estrogen suppression the only reason for side effects? If the study found similar side effects at all doses tested, it would seem so, but that is the question I wondered about.
I don't know if side effects would be better on a lower dose. I didn't have bad ones on the full dose so I stuck with it for 5 years.