Lack of hot flashes on Tamoxifen

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hope70
hope70 Member Posts: 47

Hi Ladies,

I am 43 y.o.  premenopausal. Started Tamoxifen  March'14. Had to increase dose from 20 to 40 mg due to the CYP2D6 metabolism test result ( intermediate metabolizer). As of May 9 th  I am taking 40mg. I do not  experience any hot flashes. I do take medication at bedtime. I remember hot flashes and night sweats from chemo, so I expected something similar from Tamoxifen. Is this normal not to have hot flashes on Tamoxifen? I am worried that  the medication is not working. 

Comments

  • Kicks
    Kicks Member Posts: 4,131
    edited May 2014

    Rather or not you get SE has nothing to do with rather or not it's working.  I never had any 'hot flashes' when I went through natural menopause at 44 in 1990.  I had none on chemo (A/C and Taxol) and have not had any during my 4+ years of Femara/letrozole.  We are each so unique and our bodies react differently to different things.  'Hot flashes' are but one possible SE (many do experience them) but it is just that a SE like many 'things' are and some might experience them - others don't.  If you were given a med for other health issue and you did not develope any of the possible SE, would you think they weren't working?

  • besa
    besa Member Posts: 1,088
    edited May 2014

    I second what Kicks posted.  I took tamoxifen for 5 years without a single hot flash.  None of my doctors had any issue with this.  I also did not have any hot flashes when I went through natural menopause.  I just considered myself lucky. 


  • corky60
    corky60 Member Posts: 726
    edited May 2014

    I agree with Kicks and besa.  I've been on tamoxifen for three months without a hot flash or night sweats.

  • hope70
    hope70 Member Posts: 47
    edited May 2014

    thank you ladies!!!

  • keepthefaith
    keepthefaith Member Posts: 2,156
    edited May 2014

    hope70, I have just started Tamoxifen. So far, no SE's. I am curious about the test you mentioned though. What is the purpose of the test? Is it a standard protocol to take it while you are Tamoxifen? I am post-menopausal, but have osteoporosis, so opted against Armidex, at least for now. Thanks!

  • hope70
    hope70 Member Posts: 47
    edited May 2014

    keepthefaith,  this test is not standard, but my MO strongly suggested. It is called CYP2D6 metabolism of Tamoxifen. Apparently, some of us has genetic defects in the enzyme ( CYP2D6) that metabolizes tamoxifen into its active form Endoxifen. Endoxifen blocks estrogen receptors on cells. So it is important to make sure we get enough of it from the dose of T.   http://www.medscape.com/viewarticle/776933

    most of the insurances cover this test. 

  • besa
    besa Member Posts: 1,088
    edited May 2014
    http://infoonco.es/wp-content/uploads/2011/10/breast_cancer_2.2013.pdf
    Actually the use of CYP2D6 testing is controversial right now.  The NCCN Guidelines currently recommend not to test.  (See page BINV-J in the above link.) My understanding is that studies  looking at CYP2D6 genotype, tamoxifen use, and survival have inconsistent results.   My current insurance will not cover the test....
    http://www.jnccn.org/content/7/2/203.abstract
    From the above link:
    "The authors do not currently recommend routine testing for CYP2D6
    genotype for making clinical decisions regarding tamoxifen. Use of
    concomitant strong or intermediate inhibitors of CYP2D6
    should be avoided when alternate medications are
    available. Ongoing research is directed toward identifying other
    polymorphisms
    that may influence the efficacy and safety of
    tamoxifen, other hormonal agents, and chemotherapies used to treat
    breast cancer.
    The hope is that in the future, not only
    tumor-associated factors but also germ-line host genetics can be used to
    determine
    whether a woman should receive treatment, and with
    which specific agents, to prevent breast cancer recurrence or death or
    avoid drug-related toxicities.
    "

    The thought is that other genes (polymorphisms) besides CYP2D6 may be playing a role.  The feeling is that consistent, good data needed to decide about testing is just not available yet....



  • hope70
    hope70 Member Posts: 47
    edited May 2014

    besa, that is why it is not a standard of care yet.  It is relatively   inexpensive test ( $200-300)  . From what I have been reading the results of multiple studies were different , as well as in post menopausal women only.  

    There is a topic about this test on breastcancer.org.    https://community.breastcancer.org/forum/73/topic...

    There is a genetic lab that does the testing http://youscript.com/healthcare-professionals/wha...

  • keepthefaith
    keepthefaith Member Posts: 2,156
    edited May 2014

    Thanks for the info ladies! I haven't seen any SE's yet. A light night sweat last night. 

    Have a great day~

  • Lojo
    Lojo Member Posts: 303
    edited May 2014

    I just saw this

    http://link.springer.com/article/10.1007/s10549-014-2963-1

    Suggesting that hot flash severity is inversely correlated with endoxifen levels. There's also another CY gene variant noted. It sounds like it's just not clear without prospective studies. Still wonder if I should ask about cyp2d testing at my next appointment. Argh

  • besa
    besa Member Posts: 1,088
    edited May 2014


    Yes - my personal take on things is that the jury is still out for CYP2D6 testing.  I decided not to test but that is just my view and in retrospect it may turn out that I was wrong.  Lot of times there are contradictory reports and then hopefully after some time things become clearer and a consensus is reached.   (Also as an aside when looking at published articles and trying to figure things out- all medical journals don't carry the same weight.  It is much more prestigious and difficult to get a study published in certain journals. ) From my perspective you have nothing to lose by talking to your doctor about testing - it will just give you more information.  I may help you decide what you want to do.  (Thought I didn't have hot flashes I clearly did have some side mild effects from tamoxifen -- I lost weight while taking the drug.  I had very occasional leg cramps. And I had an endometrial polyp that needed to be dealt with.)

  • Annette47
    Annette47 Member Posts: 957
    edited May 2014

    My understanding is that the presence or absence of side effects doesn't necessarily indicate anything about the effectiveness of Tamoxifen, but I also wanted to comment that I didn't have any hot flashes for the first 5-6 months I was on it, had a few the following fall and hardly had any all winter but now that the weather has warmed up again I am having more of them.    Point being, just because you've escaped them so far doesn't mean you will never get them from it.

  • keepthefaith
    keepthefaith Member Posts: 2,156
    edited May 2014

    When I asked my MO about post-menopausal symptoms while taking therapy, she suggested that it would be similar to the symptoms you had when peri-menopausal, if you have gone thru it. I think I am going to ask her about the test anyway, to get her take on it. I know there is always new information, treatment and research, but sometimes it seems as though we are still in the dark ages....I hate things to be so gray!

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