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.

Interested in more discussions like this? Go to the Breast Cancer Support Group.

I refused AI after my chemo and radiation for a 2mm tumor removal. That was 5 years ago and so far I am cancer free. My menopause was o miserable emotionally, I knew I didn't want to go through that again.

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I don’t understand why they don’t test estrogen levels and avoid over dosing people unnecessarily. Someone on this site shared a study showing leteozole had a 48 hour life and taking it every other day kept estrogen away and reduced toxicity. It was a study out of the university of Arizona but it was small and the treatment protocols weren’t adjusted. I plan to speak with my oncologist about it. But I recall other women posting that they started taking it every other day to reduce symptoms.

As for bones, start lifting weights. You can Google exercise for bones and you will get a lot of ideas if you want to do it at home. I also do yoga for stretching joints and breathing and walking.

Stay active and move your joints. I too am 71, I started leteozole a year ago and have more stiffness than ever in my knees and I have arthritis in some places in my body. I had slight osteoporosis in my hip but I won’t go on more medications so I walk and lifer weights and have adjusted my diet. My DO agrees with my plan - doesn’t like the drugs that treat osteoporosis.

I think these AI meds are a blessing and a curse. They may prevent cancer from returning but they affect the quality of your life. My cancer was stage 1A without lymph node involvement and I had bilateral mastectomy last February with clean margins. I was told even with letrozole my cancer has an 8% chance of returning. It is a hard decision but there are women who decide not to take them at all. There are days I wonder about that approach.

Hang in there everyone. Now I have four more years to go. I will see whether switching to another AI med is something my oncologist would like to do. I hear they all have the same side effects. She chose Letrezole because it is the choice for invasive lobular breast cancer which was the kind I had. So again I find myself hesitant to try something else. I feel stuck between doing the best thing and feeling my best.

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Docs will often prefer to switch AIs rather than dose adjust for side effects because they prefer to stick with approved doses. I'm also in Kisqali where starting dose is 600mg daily. Because of neutropenia, dose was reduced to 200mg. Since we all metabolize meds differently and may be taking other meds that slow metabolism, my 200mg may lead to same concentrations as 600mg in someone else. I was diagnosed at stage 4 with lobular carcinoma and have been at this dose for 3 years. Fingers crossed.

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Profile picture for jmh22 @jmh22

Docs will often prefer to switch AIs rather than dose adjust for side effects because they prefer to stick with approved doses. I'm also in Kisqali where starting dose is 600mg daily. Because of neutropenia, dose was reduced to 200mg. Since we all metabolize meds differently and may be taking other meds that slow metabolism, my 200mg may lead to same concentrations as 600mg in someone else. I was diagnosed at stage 4 with lobular carcinoma and have been at this dose for 3 years. Fingers crossed.

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@jmh22 I think oncologists rely on research rather than seeing the humanity involved.

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Profile picture for richandjanice @richandjanice

Is there any other option...my estrogen is already extremely low and I have osteoporosis but they are still recommending letrozole...really don't want to hurt my body more

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@richandjanice
Seems like if you estrogen is extremely low, perhaps you should stop taking it? But, consult you OB?GYN doctor, he/she will be able to give you a level of hormones that would be right for you. Mine is 95% and I just started Exemestane. I am no doctor but you will be producing estrogen all your life. So, it shouldn't be non existent. NOT LETROZOKE lots oa side effects. You have to ask yourself
How long have I been on this?
What do I feel like what is their overall plan?
Where are you in the recovery?
blood work? Testing of other stuff, heart, bones,etc.
Conversations about how you feel?
Ask, how bad is my prognosis now?
What is my chances of survival now?

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I have wondered that myself. A woman weighing 130# gets the same dose as woman weighing 230#.

I brought this up to my oncologist when I had my first round of breast cancer and was having a ton of side effects. Her answer was, "well, that is the dosage they used for the clinical trials". I don't think that is a good enough answer, but it is all I got.

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Profile picture for angele2times @angele2times

@richandjanice
Seems like if you estrogen is extremely low, perhaps you should stop taking it? But, consult you OB?GYN doctor, he/she will be able to give you a level of hormones that would be right for you. Mine is 95% and I just started Exemestane. I am no doctor but you will be producing estrogen all your life. So, it shouldn't be non existent. NOT LETROZOKE lots oa side effects. You have to ask yourself
How long have I been on this?
What do I feel like what is their overall plan?
Where are you in the recovery?
blood work? Testing of other stuff, heart, bones,etc.
Conversations about how you feel?
Ask, how bad is my prognosis now?
What is my chances of survival now?

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@angele2times Estrogen is continued to be produced in females after menopause by the fat in their body. That is one reason they talk about taking off excess weight. I found that impossible as Arimidex caused me to gain twenty-five pounds over the five years on was on it and NOTHING I did would make a single pound leave. NOTHING! I had never been overweight in my life until I had to take Arimidex. I recently read that selenium degrades estrogen, and I am taking it now.

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Anastrozole! Anyone else on this drug? I am more tired than I’ve ever been plus it is not good for my bones so the oncologist has added Fosamax which has its own set of side-effects. Need advice from others who are walking this walk!

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Profile picture for angele2times @angele2times

@richandjanice
Seems like if you estrogen is extremely low, perhaps you should stop taking it? But, consult you OB?GYN doctor, he/she will be able to give you a level of hormones that would be right for you. Mine is 95% and I just started Exemestane. I am no doctor but you will be producing estrogen all your life. So, it shouldn't be non existent. NOT LETROZOKE lots oa side effects. You have to ask yourself
How long have I been on this?
What do I feel like what is their overall plan?
Where are you in the recovery?
blood work? Testing of other stuff, heart, bones,etc.
Conversations about how you feel?
Ask, how bad is my prognosis now?
What is my chances of survival now?

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@angele2times presurgery...they want to hold nodules or shrink before surgery. I won't agree to it afterward. Postponing surgery is a life choice for me. Summer plans

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Profile picture for katie816 @katie816

@angele2times Estrogen is continued to be produced in females after menopause by the fat in their body. That is one reason they talk about taking off excess weight. I found that impossible as Arimidex caused me to gain twenty-five pounds over the five years on was on it and NOTHING I did would make a single pound leave. NOTHING! I had never been overweight in my life until I had to take Arimidex. I recently read that selenium degrades estrogen, and I am taking it now.

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@katie816
Hi!

did your symptoms go away, weight gain. Who suggested selenium? Hopefully this works.

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