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Daft question here

Community Champion

Re: Daft question here

Hello again Joemic , 


Yes,  I have no issue with meds as long as I feel confident that the benefits outweigh the risks and I don't end up on a string of other meds to counteract side effects etc.  My tumour tested 8/8 for oestrogen receptors and as side effects are manageable for now,  this is  enough reason for me  to continue with Anastrazole at the current time!   I know what you mean about wanting to know the reasoning behind things.... I wish I didn't sometimes.


After writing my response,  it also struck me that blood level measurements of circulating oestrogen would be of little use for Tamoxifen users as Tamoxifen does not act upon oestrogen production but aims to block circulating oestrogen's action on cell receptors.  It may be of interest to see if the body compensates by trying to increase production when there are attempts to block the action of it. 


I suppose for AI users,  there is an assumption that ovarian oestrogen production has greatly decreased by natural or enforced shut down so any circulating levels drop dramatically.  Estrone is then made from converting androgens/testosterone produced by adrenal glands and ovaries (in declining proportions post menopause)  via the action of aromatase.  As AIs inhibit Aromatase,  then it is assumed you don't have much circulating oestrogen so why test for it?  I am not entirely convinced by this and personally would like to have had levels tested before and after use or even now!  It can be a blessing not to have had too many severe AI side effects yet but not when you read that some research concluded that the less side effects,  the less effective the meds blah blah. It  may make people wonder if it is inhibiting as much aromatase as it should and/or what level may be still circulating.  


Not an issue for me at the moment, but it also seems  unclear how being overweight increases risk if a person is already receiving anti oestrogen treatment.  It never seems clear if the issue is that actual oestrogen is stored in fat cells or that fat cells may be loaded with aromatase and thus potential for more oestrogen to be produced and circulate.  We all get the same dosage of AI at the moment so perhaps the medics need to make it clear about what exactly are the increased risks of ER+ breast cancer recurrence ,if any,  if you are overweight and already receiving AIs ?  My understanding is that being overweight is a risk for post menopausal breast cancer rather than pre menopausal breast cancer (although it may increase risks for other cancers at whatever stage of life) as the type of oestrogen made after menopause can make cells divide faster especially in the breast and womb.


  I have even seen estrone referred to as the Carcinogenic oestrogen.  Great eh?  Estradiol forms us,  Estriol comes into play and is supposed to be protective during pregnancy and then Estrone comes along to try and finish us off.  Lovely.  How fascinating our bodies,  their workings and nature are.... 


 I better sign off now before I get carried away (literally as well as metaphorically).

Chick 🐣  x


Re: Daft question here

Thank you for your reply Chick, I found it really informative, I do intend to ask my Oncologist if I ever see her again - just because I like to know the reasoning behind things.

I was having the same thoughts that you mentioned in your post about levels and whether the meds are working or not. Surely in this day and age there must be some sort of reliable test, as you say some women have terrible side effects from the medication but this does not mean that it is lowering their levels and vice versa no or few side effects does not mean the medication is not successfully doing what it is supposed to do.

5 or 10 years is a long time to stay on medication that is maybe having no or little effect and the side effects are outweighing the benefits. It would just give women the opportunity to make an informed decision on whether to continue with a medication that might be unnecessary. Can you tell I'm not a big fan of taking medication unless it is necessarySmiley Frustrated.

Anyway hopefully in the future there will be such a test but in the meantime as you say we can only make decisions the best we can in the here and now. 


Joemic x 

Community Champion

Re: Daft question here

Hello Joemic, 

Not a daft question at all but a very logical one.  Hopefully someone with more knowledge can give a more informed response to it. Perhaps you might like to post your question in the Nurses section. 


My understanding is that there is no specific horrmone called oestrogen but there are 3 different main forms.  Estradiol  which is produced in the ovaries so I assume it is the pre menopausal dominant form,  estriol which is dominant during pregnancy and estrone which is created from organs/fat tissue.  and hence I assume is the post menopausal dominant form created from the action of aromatase on androgens/testosterone.


As far as I know,  it is not as simple to measure estrone levels as it is, for example,  to measure blood sugar levels.  Just like when they do the test for whether someone has hit menopause,  they don't do a direct measure of estradiol levels but measure the. level of follicle stimulating hormone (FSH)  in the blood.  Even such results as theses can yield false negatives and positives.


I also heard that any blood levels of oestrogens can fluctuate greatly rendering any given measurement relatively uninformative.  However perhaps someone should tell the bodybuilders who use aromatase inhibitors as they don't seem to have a problem testing their blood levels. 


I was told that measuring would have little purpose as no safe level has been determined/the level it takes to feed a tumour to life.  But surely it would  be useful to know whether the hormone meds are having a lowering effect, especially if people are not experiencing too many side effects and are debating efficacy of medication based on that!  You would also think testing could alert people to drug resistance etc. at an early stage. 


Whether using tamoxifen to block action of circulating oestrogen or aromatase inhibitors like Letrozole to inhibit the production of aromatase and stop the conversion to estrone,  I think the aim is to reduce the action of oestrogen  to zilch. I think aromatase inhibitors  have been shown to reduce levels by over 95% .  I don't  think there is a recognised unsafe low level, apart from when people have had enough of debilitating side effects and how much this is affecting their quality of life.  Yes you are right that we can be at increased risk of other things from oestrogen depletion,  for example, osteoporosis,  increased cholesterol,  effects on mental health.  In the end we just have to make the best informed choice for ourselves.  There are no guarantees with any treatments. 


Chick 🐣 x






Re: Daft question here

I just started a few weeks ago nine years and 48 weeks ... to go . No mention of blood tests I suppose monitoring us is enough . TBH had more than enough blood tests in past nine months ! 


Daft question here

Hi Ladies


It may be a daft question but when we are on Letrozole for long periods do we have blood tests to determine our oestrogen levels? I just wondered because if we are ER+ how do we know if our oestrogen has lowered enough with the hormone therapy or not.


Just a random thought (I'm full of themSmiley LOL), surely if the levels go too low we are at risk of all sorts of things and if it's still high, well we all know what we are at risk of there.


Joemic x