Why are dosages for estrogen suppression drugs one-size-fits-all?

Posted by gldilli @gldilli, Mar 28, 2023

Why is the dosage for Anastrozole (and any other AI) the same for everyone no matter your weight or size? Does this-one size-fits-all approach have an impact on side effects, risk of recurrence, etc. I’d like to know what the medical community has to say.

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Profile picture for thora902 @thora902

That is a good question. Why don't oncologists test for estrogen and estradiol levels? I have not been seen by one oncologist who tests these levels. When I suggest it, they all refuse.

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Hi
I have been wondering the same thing lately why would they not test your levels first to see where your estrogen is at because how do they know how low it is especially when your post menopausal

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Profile picture for sue417 @sue417

Hi
I have been wondering the same thing lately why would they not test your levels first to see where your estrogen is at because how do they know how low it is especially when your post menopausal

Jump to this post

@sue417

I had to “fight” with my oncologist to test me - refusing to start anastrozole until tested. His response is it’s not clinically indicated. Sadly there isn’t enough research. I’m 77 yo, early stage 1 BC, lumpectomy, 5 day radiation, normal weight for height, already have high BP, osteoporosis and heart disease. I feel better knowing my estrogen is below 15 (in case I decide to stop taking due to bad side effects).

I wish they did a more sensitive estrogen level test so I’d know how much under 15 my level is. There are a few studies about what % drop one can expect when on AI. If my estrogen level is actually 5 then an 80% drop might bring it lower than research says needed. That is, if there were research. One size fits all standard of care seems wrong.

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Profile picture for kherman8434 @kherman8434

@sue417

I had to “fight” with my oncologist to test me - refusing to start anastrozole until tested. His response is it’s not clinically indicated. Sadly there isn’t enough research. I’m 77 yo, early stage 1 BC, lumpectomy, 5 day radiation, normal weight for height, already have high BP, osteoporosis and heart disease. I feel better knowing my estrogen is below 15 (in case I decide to stop taking due to bad side effects).

I wish they did a more sensitive estrogen level test so I’d know how much under 15 my level is. There are a few studies about what % drop one can expect when on AI. If my estrogen level is actually 5 then an 80% drop might bring it lower than research says needed. That is, if there were research. One size fits all standard of care seems wrong.

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@kherman8434
I don't know what has to happen so that they will start to listen to patients because I think it's better to know what your numbers are for sure before starting that med.
I did not take an AI my breast cancer was dcis her2 negative stage 0. I had 20 rounds of radiation. 1 lymph node removed which was clear.
They immediately took me off my hormone therapy the day my GP told me I had breast cancer which put me into one horrid year of menopause. I had been on it for 13 years and I felt great. Now I feel like crap and I'm exhausted all the time and have brutal hot flashes still it's so frustrating.

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Profile picture for sue417 @sue417

@kherman8434
I don't know what has to happen so that they will start to listen to patients because I think it's better to know what your numbers are for sure before starting that med.
I did not take an AI my breast cancer was dcis her2 negative stage 0. I had 20 rounds of radiation. 1 lymph node removed which was clear.
They immediately took me off my hormone therapy the day my GP told me I had breast cancer which put me into one horrid year of menopause. I had been on it for 13 years and I felt great. Now I feel like crap and I'm exhausted all the time and have brutal hot flashes still it's so frustrating.

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@sue417 Yes, I agree with you. The docs test your cholesterol level before putting anyone on statins. Why not before AI's?
I'm on Anastrozole and I take it every other day as I'm very small and only weigh 100 lbs but haven't told my doctor because he and the NP just don't listen! When I complain of side effects they act like I'm speaking another language and tell me to go to other doctors to fix the side effects. It's just astonishing to me that these AI's aren't prescribed in lower dosages. I've told them before that I was taking Exemestane every other day (before I stopped) and was dismissed and told it was "ineffective". Is it just so they don't get sued for malpractice? Anyway, I'm doing just fine now as I have taken my health into my own hands and will continue to take it every other day. So far, so good!

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Profile picture for sue417 @sue417

Hi
I have been wondering the same thing lately why would they not test your levels first to see where your estrogen is at because how do they know how low it is especially when your post menopausal

Jump to this post

@sue417
It is my understanding that the hormone blockers we take actually block the estrogen receptors in the bone marrow, where dormant breast cancer cells can hide for years. So it would not matter how much estrogen is in our body. So no need to test estrogen levels. It just matters that dorment cancer cells hiding in our bone marrow are blocked from natural estrogen therefore cannot be fed and hopefully die out in 2 to three years. We take the hormone blockers for 5 years to be sure. I'm not sure I'm explaining this correctly. It's complicated. I have been on 3 different blockers. I am taking Tamoxifen now (Even though I'm past menopause). When I first started I would take it for two weeks and then stop for 2 or 3 days. Just needed a little break.. Then start back up. I think my body has finally adjusted. Now I have very little side effects. If we don't get the dormant cancer cells to die out, they will return as cancer somewhere in our body. That becomes an automatic stage 4 cancer. No cure for that, just treatment. So for me, I'm going to eat a little better, workout a bit, take up meditation (meditation helps calm the vagus nerve and can help with hot flashs) and continue to take my blockers. Good luck to all of you and stay strong.
Kristine

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Profile picture for kherman8434 @kherman8434

@sue417

I had to “fight” with my oncologist to test me - refusing to start anastrozole until tested. His response is it’s not clinically indicated. Sadly there isn’t enough research. I’m 77 yo, early stage 1 BC, lumpectomy, 5 day radiation, normal weight for height, already have high BP, osteoporosis and heart disease. I feel better knowing my estrogen is below 15 (in case I decide to stop taking due to bad side effects).

I wish they did a more sensitive estrogen level test so I’d know how much under 15 my level is. There are a few studies about what % drop one can expect when on AI. If my estrogen level is actually 5 then an 80% drop might bring it lower than research says needed. That is, if there were research. One size fits all standard of care seems wrong.

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@kherman8434 my situation is similar, diagnosed in August with early stage 1 ILC, lumpectomy & 5-day radiation. I'm 72. I take a half-dose (10 mg) of Tamoxifen which will hopefully help my bones & I'm doing ok. In case that might be an option for you.

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Profile picture for knm6302 @knm6302

@sue417
It is my understanding that the hormone blockers we take actually block the estrogen receptors in the bone marrow, where dormant breast cancer cells can hide for years. So it would not matter how much estrogen is in our body. So no need to test estrogen levels. It just matters that dorment cancer cells hiding in our bone marrow are blocked from natural estrogen therefore cannot be fed and hopefully die out in 2 to three years. We take the hormone blockers for 5 years to be sure. I'm not sure I'm explaining this correctly. It's complicated. I have been on 3 different blockers. I am taking Tamoxifen now (Even though I'm past menopause). When I first started I would take it for two weeks and then stop for 2 or 3 days. Just needed a little break.. Then start back up. I think my body has finally adjusted. Now I have very little side effects. If we don't get the dormant cancer cells to die out, they will return as cancer somewhere in our body. That becomes an automatic stage 4 cancer. No cure for that, just treatment. So for me, I'm going to eat a little better, workout a bit, take up meditation (meditation helps calm the vagus nerve and can help with hot flashs) and continue to take my blockers. Good luck to all of you and stay strong.
Kristine

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@knm6302 I'm 72 & I take a half-dose (10mg) of Tamoxifen (started Jan. 1st) & I'm doing ok. Most frustrating is a slight weight gain, but I'm working on that! I agree with you, that our bodies adjust over time.

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Profile picture for knm6302 @knm6302

@sue417
It is my understanding that the hormone blockers we take actually block the estrogen receptors in the bone marrow, where dormant breast cancer cells can hide for years. So it would not matter how much estrogen is in our body. So no need to test estrogen levels. It just matters that dorment cancer cells hiding in our bone marrow are blocked from natural estrogen therefore cannot be fed and hopefully die out in 2 to three years. We take the hormone blockers for 5 years to be sure. I'm not sure I'm explaining this correctly. It's complicated. I have been on 3 different blockers. I am taking Tamoxifen now (Even though I'm past menopause). When I first started I would take it for two weeks and then stop for 2 or 3 days. Just needed a little break.. Then start back up. I think my body has finally adjusted. Now I have very little side effects. If we don't get the dormant cancer cells to die out, they will return as cancer somewhere in our body. That becomes an automatic stage 4 cancer. No cure for that, just treatment. So for me, I'm going to eat a little better, workout a bit, take up meditation (meditation helps calm the vagus nerve and can help with hot flashs) and continue to take my blockers. Good luck to all of you and stay strong.
Kristine

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@knm6302 thank you for the explanation. I had no idea. Now I understand why my oncologist said taking Anastrazole for an extra 2 years (7 years) reduces the risk even further.

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Why don’t oncologist explain the information about cancer hiding in bone? What if you were stage 1A and no cancer in lymph nodes with clean margins at bilateral mastectomy ? I am on hormone blocker letrezole and my estrogen levels were never tested. I have read one study which someone posted on this site su suggesting letter results stays in your body for 48 hours therefore you could really take it every other day and have the same result of blocking any estrogen in your body. When I see my oncologist the next time I plan to ask her these questions and get more inside into how this drug works. Praying for no worse side effects of what I currently have which is hot flashes and joints that ache. But like the other contributor, I work out regularly and eat super healthy and yoga and meditation all which I think help the joints and the hot flashes. Hang in there ladies we got this, but I’m so thankful for all of you sharing your insights and experiences at least I know we’re not alone because you’re right doctors really don’t listen. And I have found that oncologist in particular don’t want to hear you complain.

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I understand your frustration. I always want all the answers too. Oh.... something you mentioned about having cancer in the bones.... it is my understanding that it is dormant cancer cells hiding in the bone marrow not actual bone cancer. And before we even found out about our breast cancer, those cells were traveling through our body.
I recently went to a breast cancer symposium. It was soooo informative! And in response to "why do our doctors not explain these things to us"? One of the speakers at the symposium told the audience that there are no new books being published on breast cancer because research and treatments are changing so fast, by the time it's published, it's out of date. The treatment I had 2 years ago would be different if I were diagnosed today. So I believe doctors just go by the book, so to say, until something is brought to their attention and it has to be medically accepted, in fear that they could be sued if they said, "sure go ahead and try that and let me know how it affects you."
So bring it up to your docs, and don't let them dismiss your report to them. You are the boss and they work for you. I ask my doctor many questions and sometimes I ask the same question twice (I chalk that up to chemo brain). I wish you all well! Good luck and stay strong.
Kristine

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