Topic: Tamoxifen and CYP2D6 testing

Hi YoYo,

The testing is not routine and my oncologist was neither supportive nor encouraging. However, my research indicated 50% of women prescribed tamoxifen do not metabolize it properly, and if I was going to take this drug for 5 years, I wanted to know it was going to work for me.

There are several labs in the US that do this testing. (You can google CYP2D6 and find them.) I selected Genelex (genelex.com) in Seattle. They were quick, efficient, accurate, helpful and the cheapest. They sent a package; I swabbed my cheeks; returned it and soon thereafter got the results. Also, they provide a software program where I can check for drug/food interactions.

Yes,  paid for it out of my pocket - $Can334 (including exchange).

As it turns out, I am an "intermediate" metabolizer, one of the 35% who sort-of metabolize tamoxifen. My onc now is interested and has upped the usual dosage - the first, I understand, at the Cancer Clinic in Calgary! And so far so good - 27 days down, 4years 339 days to go ;-)

where r u from?

My onc said that if you are having hot flashes, then you are probably metabolizing.  I started Zoladex at the same time as Tamoxifen, and did have hot flashes,  She said that you usually dont have hot flashes right away from Zoladex and my hot flashes are probably from the tamoxifen which would show i was a good metabolizer.  Anyway, I thought it was important enough to be tested.  So I shelled out $400, had a blood test at the hospital and guess what!  I am an IM.  i got the result on-line as my hospital has a patient portal that allows me to read all my results.  I am seeing my onc on Tuesday and will ask what to do.  I am thinking that I will be switched to an AI.

yoyo,

I am also being followed at the Jewish.  Who are your doctors?  Mine is Dr Margolese.  I just started Tamox on Friday, and all I feel is incredible nausea.  I think I will ask him next time I see him (Jan), if I could take the test.

I have had the prescription for 2 months and finally did it and started taking the medication.  I don't want to take it for 5 years and learn that I don't metabolize it well. 

Hello Covertanjou,

I am seeing Dr. Ferrario and I asked him about the test and he did not know about it beeing done.  But he was open.  I have  not asked again as I am not there yet but will follow up later.  Knowing that I have the option to get it done on my own is good too (thanks bcamnb for the info!).

Let me know what you find out.  I am trying to sort out surgery and reconstruction and lymph nodes and chemo so probabaly won't be geeting into this again for a while.

Yo

YoYo,

You have PLENTY on your plate to put this decision to the back of your mind for the time being. I know how totally overwhelming all the need-to-know-be-on-top-of info is. I had NO IDEA six months ago I'd ever have to know any of it!!!!! Best wishes with all the up-coming procedures/surgery et al.

Mary - hope the nausea continues to diminish

Caroline (in Calgary) 

hi all, i just found out about this test and phone my oncologist.  i was told that the credit valley hospital in mississauga, ontario is not going to have any of their patients take this test...not happy with this as i do not think they are being supportive if we are interested...i found out about it from a session at wellspring (a caring organization for those living with cancer) from an oncologist at a brampton hospital...he is advising his patients that it exists and if they want to pay for it he will arrange for it to be done..  i am now going to have to order it and do it myself without the guidance of my oncologist...any other women being treated at credit valley if it applies to them and if they are interested should contact their onc and ask for the test...the more pressure applied might make an impact....

Hi Caroline - I live in Manitoba.  I went to the Mayo Clinic for the cyp2d6 test and am an intermediate metabolizer also.  I am taking 20 mg of tamoxifen.  I was wondering what doseage your oncologist has now perscribed.

Thanks,

Bev

Thanks for the info Caroline.  I am seeing my oncologist tomorrow.  I agree, there is a lot of controversy on the cyp2d6 test.  The oncologist that I saw at Mayo was one of the leaders of it yet admitted that everyone is not on board with it. 

Yes, I did have chemo and rads.  I am also on a clinical trial with zometa.  Chemo has put me into menopause likely permanently.  I am 46.  

Thanks Again,

Bev

I went to Mayo in Feb/09.  (just before I started chemo)  We went to get a 2nd opinion and also for the cyp2d6 test.  (Things happened before my diagnosis that we were not happy about.)   We did not know at that time that you could do it how you did it.  I had my surgery, chemo and rads in Winnipeg (where I live).  We met with an oncologist at the Mayo and we did leave with some reassurance that the treatment that I was going to get in Canada was just as good.  I am lucky that Wpg has such an incredible plastic surgery breast reconstruction team.  One of the surgeons is originally from Mayo.  For the size of our city, we are extremely fortunate.

Hi Beverly,

Really interesting and I hope we can stay in touch to see how your treatment unfolds.

I lived in 'peg for 10 years (thus the M part of my handle!), so can relate a bit with where you are!