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Testing Baseline Hormone Levels before starting Tamoxifen

futura Member Posts: 14
edited January 2022 in High Risk for Breast Cancer


I will be starting Tamoxifen due to ADH. My doctor did not suggest any tests to measure hormone levels before starting the treatment.

Can you share your experience if your doctor has ordered any tests?

Thank you.


  • threetree
    threetree Member Posts: 1,275
    edited August 2021

    I take an AI, letrozole, not Tamoxifen, but I have been told that there is no routine testing of hormones for any of these endocrine treatments. I asked my oncologist why and all she said was, "We just don't do that." Others on these boards have wondered the same thing and heard the same thing, i.e. they just don't do the testing. Some say it has something to do with how circulating blood levels that would be obtained via blood draw are not at all the same as the levels that might actually be in other body tissue, e.g. breast tissue, so that the tests would really show nothing. That's all I know, hope this helps. It all remains a conundrum to me.

  • elainetherese
    elainetherese Member Posts: 1,625
    edited August 2021


    If you're pre-menopausal, your oncologist will presume that your ovaries are producing estrogen. If you're post-menopausal, your oncologist will assume that your ovaries are not. I've been taking Zoladex for over six years to shut down my ovaries so I can take an aromatase inhibitor. Right now, I'm on a Zoladex vacation to see if I'm post-menopausal. After two months, my oncologist will test my estrogen levels. If they're low, no more Zoladex. If they're high, there's more Zoladex in my future.

  • futura
    futura Member Posts: 14
    edited August 2021

    Thank you Three Tree & Elaine for your responses and help.

  • BCat40
    BCat40 Member Posts: 121
    edited September 2021

    They don’t test because it doesn’t matter how high or low your estrogen levels are. The purpose of tamoxifen is to block whatever estrogen you do have from binding to your breast cells (of course it also blocks estrogen from binding to other cells as well, which is why some women have side effects).

    They will test estrogen levels for Zoladex or lupron because if your estrogen is so low that you are in menopause you can take an AI without Zoladex or lupron on top. If you are not in menopause you can’t take an AI by itself so need to have the injections to chemically shut down your ovaries. The AI drugs work by a different mechanism than tamoxifen. They prevent other glands in your body from producing estrogen in the first place rather than blocking circulating estrogen from binding with your cells.

  • pt1234
    pt1234 Member Posts: 9
    edited January 2022


    I see you had cancer in 2014 . Was there any recurrence . What did you follow , not to get