CYP2D6 Test

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orange1
orange1 Member Posts: 930
edited June 2014 in HER2+ (Positive) Breast Cancer

See thread "Important for Her2+ on Tamoxifen" for why you should consider this test.  Here are some suggestions on how to get the test.  I copied this from the hormonal therapy board:

Ideally, your doctor should order the test.  Mayo Clinical Laboritories performs the blood test.  If the lab your onc uses does not have an account with Mayo (most large institutions probably do), its very easy for his staff to set up.  See link.

http://www.mayomedicallaboratories.com/order-tests/new-client.html

If after much, much pestering, your onc will not agree to do the test you can get it yourself over the internet with a cheek swab.

see link.

http://www.tamoxitest.com/

I suggest pestering your onc to order the test.  If your onc won't do it, maybe your PCP or gyne will.  At first many will refuse.  Eventually many will probably give in, especially if you pester alot, or as lexislove suggested, manage to conjure up some tears - just to get you off their backs.  With Mayo, the quality of the test is almost certainly high.  I have no reason to suspect the tamoxitest is not okay, but they don't have the reputation of Mayo.

In addition to ensuring you are a good or "extensive" metabolizer of tamoxifen, it is important to remember to not take any drugs that interfere with tamoxifen metabolism.  Unfortunately there are many that do, including many antidepressants and many antihistamines.  If in doubt, ask your pharmacist to check for you.  He or she will probably be grateful for a question that utilizes their training (instead of the usual insurance questions) 

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  • lexislove
    lexislove Member Posts: 2,645
    edited August 2009

    Awsome...such good info. This should be "bumped " daily Orange...

    TY

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  • Warrior517
    Warrior517 Member Posts: 355
    edited August 2009

    Hi Orange!

    I just wanted to thank you for making us Her2 and Estrogen girls more aware!! I saw my oncologist today and discussed these findings. One thing the dr said that has not come into play is the early stage BC pts that have been on Herceptin and how that all comes into these recent findings....Nevertheless, they are sending my blood to Univ of Michigan for the preliminary test and if that comes back positive..then off to Mayo. She said the test at Mayo can take up to 3 weeks. I didn't have to pester...I just 'told" them...I need this. I tend to be aggressive in what I feel I need..lol   So..I assume if I am NOT metabolizing Tamoxifen then I should do a hyster and be switched to AI??? Does that sound right?   Thanks again for being such a wealth of knowledge!!!

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  • orange1
    orange1 Member Posts: 930
    edited August 2009

    Warrior -

    I'm glad you found the information useful.

    Regarding your question - yes, Mayo onc (Dr. Goetz) suggested ovarian ablation and AI for poor metabolizers.  Unfortunately, we did not discuss prognosis on tamoxifen or his recommended approach for Her2+ intermediate metabolizers (IM).  If you turn out to be an IM (approximately 30% of caucasians are IMs), and if you have the resources, I suggest going to see him and asking him directly.  Otherwise, if it were me, I'd probably go with the AI.

    I understand that in the general hormone receptor positive population, (including both Her2+ and Her2-), the response to hormonal therapy is somewhat proportional to the degree of ER expression. Therefore it may be possible, that for a very low degree of ER positivity (say < 5%), it may not be worth while to have the hormonal treatment if it requires ovarian ablation.  However I don't know how this plays out for just the population of Her2+ (without the Her2- ladies confounding the statistics.)  If you have a very low degree of ER+, it may be worth discussing with him as well. 

    Good Luck - and let us know how your test turns out.

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  • orange1
    orange1 Member Posts: 930
    edited August 2009

    Bump for tamoxifen and Her2+ thread

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  • Mocity
    Mocity Member Posts: 451
    edited August 2009

    I guess I should ask my Onc for this test???  I am not taking Herceptin.  My Onc has me on Lupron to suppress any Estrogen.

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  • orange1
    orange1 Member Posts: 930
    edited August 2009

    CristlC - If you are taking tamoxifen, I highly recommend it.  If you haven't seen it yet, take a look at the thread: "Important for Her2+ on Tamoxifen" for an explanaition of why this is so important for Her2+ tumors.

    For a really technical explanation see "Tamoxifen and Her2+ Cancer"

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