Tamoxifen and CYP2D6 testing

bcamnb

Tamoxifen and CYP2D6 testing

bcamnb

Hi,

Just wondering if other Canadians have been tested before beginning tamoxifen. I was and am delighted to know the results. How do we get the word out about this?

YoYo44

Hi,

I asked my onc about this and he said he did not know that this testing was routinely done.  How and where did you get it done?  Did you pay out of your own pocket or was it covered?

Thanks,

 yo

bcamnb

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 ;-)

YoYo44

Thanks for the info bcamnb.  I think there was a woman from Genelex posting with some good info too.

I am not there yet but will be eventually so have all the same concerns.  Being ILC I ask a lot of questions since there are differences but the clinical practice here is the same it seems.

Good luck on the next 4years 339 days !

Yo

bcamnb

where r u from?

YoYo44

I am in MTL.  Being followed at the Jewish.  Great doctors there and great care.

Yo

Anonymous

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.

AnnNYC

Even worse than being an intermediate metabolizer is being a poor or non-metabolizer -- 7 to 11% of the population -- I found out I'm in that "special" group , with two "null" alleles for CYP2D6, so I'm REALLY glad my onc had me tested -- I was completely unaware of this issue before she mentioned she was ordering this test.

covertanjou

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. 

bcamnb

Hi Covertanjou,

Are you taking the Tamox at night and with food?  Works for me - no nausea and hot flashes et al while I am asleep.

Good luck with the onc. But you do know you can do this test all by yourself (I did and it wasn't until then my onc took me seriously).

YoYo44

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

covertanjou

Caroline,

I am taking it at night and with food.  The nausea is better today, so I hope my body is getting used to it.  I will definitely look into getting the test to see if I metabolize the tamox.

Yo,

Good luck with your surgery.  You are at a great hospital and that makes a difference.

 Mary 

bcamnb

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) 

hlya

I was told by my ONC that it's not an official test and not proved yet...some famous ONC in US never used it.

InfoSeeker2008

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....

bcamnb

hi infoseeker,

I live in Calgary. I arranged the test myself. Very easy to do, so long as you are willing to pay the $US295.. I was VERY happy with Genelex in Seattle. They were helpful, knowledgeable, prompt and from what I understand VERY accurate. My onc was totally unsupportive as well. Changed his tune when we found out I was an Intermediate Metabolizer of Tamoxifen. (See my earlier post.)

 I highly recommend every woman prescribed tamoxifen get tested. Why in the world wouldn't you want to know if you didn't metabolize the drug at all/or not all that well/ or over metabolize it????? YIKES we are not cows to be herded or sheep.....

Beverly11

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

bcamnb

Hi Bev,

The Genelex lab, where I had my swabs analyzed, recommended 30-40 mg. On Oct 1, I began, and am still on 30 mg/day. A few mild hot flashes/night sweats and red cheeks in the afternoon - otherwise no problems. I am EXTREMELY careful what I eat/drink, so as not to inhibit the Tamox any further. 

From your diagnosis, I suspect you had chemo, which I did not. That may make a difference to Tamox follow up?  Also, are you pre/post menopausal. I am post. The jury is out on all this adjusted dosage. This test is so new, I don't think onc's know what to do with the results.

Good luck

Beverly11

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

bcamnb

Best of luck tomorrow.

BTW did you GO to Mayo? Why did you do that? Is that where you had your surgery/follow-up/chemo/radiation? Just curious. This journey for each of us takes many wierd twists and turns (and we could all do without ANY of them!!!)

Beverly11

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.

Beverly11

Caroline - I swear I 'still' have chemo brain!  I discussed possibly revising my doseage of tamoxifen with my oncologist and he was intrigued and will be getting back to me.  Thanks again for sharing your info.  These boards & the people on it are just amazing!!!

bcamnb

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!

jillyG

I am thinking it might be a good idea for me to get this test done.  I think I will order the kit and do it myself.  My surgeon in Calgary who is a breast cancer specialist told me that I don't need the test because there is nothing else I can take as I am pre-menopausal and because I am only 34 he says he would absolutely not recommend an ooph.  If you are a poor metabolizer and pre-menopausal do they up your dosage?  What happens in that case? 

cedarlover

jillyG

I do not want to complicate things for you, but I will share my experience. I was pre-menopausal upon diagnosis (age 43).  I sent away for the CYP 2D6 test b/c I did not want to take tamoxifen for 5 years without knowing it was doing some good.  My test came back Poor Metabolizer.  If it came back Intermediate metabolizer I would have just taken the tamoxifen.  But since it was PM, that piece of info complicated things for me.  I live in Calgary as well.  Well, I told the oncologist the result of my test and that Tamoxifen is not a good choice for me.  The oncologist said there is nothing she could do for me at the present time (meaning other treatment is not covered).  I suggested goserelin to suppress my ovaries and an aromatase inhibitor and possibly a referral to an gyne for and ooph (I am older).  That was prescribed even though does not seem regular course of action.  The goserelin is expensive $519.00 per a month and the aromatase inhibitor is $189 month which I have to pay.  At present I have insurance, but it makes me nervous because it is for 5 years and who knows financially the future.  If you have not already, check out lexilove's debate regarding this issure on the "hormone forum" as I believe she is closer to your age. 

sling99

Is the test to see if you metabolize tamoxifen just a simple blood test? I see other people mention cheek swab. My onc said she could order it for me if that will make me feel better about taking it. Is the test covered by OHIP or not?

If the result comes back as an intermediate metabolizer then would the onc up your dosage to compensate for that? If so, doesn't the risk/severity of the side effects increase also?

Caroline-H

Hi Sling. I'm 43, pre-menopausal, & from BC. I sent off for the cheek swab to Genelex in Seattle (as recommended above by bcamnb - thanks!!), paid $350 my cost but no doctor's order was needed. Results came back within a week about being an intermediate metabolizer. I've not yet talked with my team about how this affects my Tamox treatment, as am just starting chemo. However it did make deciding on the big treatment picture easier for me. I'd also found out (through a study offering OncoType DX testing) that I'm on the borderline for needing chemo, and knowing Tamox was going to be moderately effective made doing chemo an easier decision. On the Genex literature it notes I should either have a higher dose of Tamox, or an alternate tx. I imagine when my chemo is finished, I'll get a higher dose, and may consider additional options (other than aromatase inhibitors, as I'm presently pre-menopausal). I'll write back in Nov when I'll have more info on options, if anyone still wants to know then. Good luck to all of you with your journeys!

Caroline-H

An update about the test. Apparently studies have now shown that this test is no longer recommended for breast cancer, as it's inconclusive. My oncologist heard this at the December breast cancer conference in Texas. I believe the Genex site has more information about this. Also, there is no correlation that night sweats means Tamoxifen is working better than for ladies who don't have the sweats. So after other treaments (suregery / chemo / radiation), the standard treatment for premenopausal women continues to be Tamoxifen 20 mg / day for 5 years.  

Carol_Mark

Tamoxifen for 10 years based on new research I got at the Mayo clinic.

It is a small study but the survival rate increases to take a second look.

I was tested at the Mayo after leaving Canada where all 4 tumours were missed and

two negative mammograms.

Why are Canadians not more vocal in having this tested routinely especially if you were the ones unable

to metabolize this drug? We have universal healthcare but it is still paid for by taxes and not free but substandard.

An former nurse who is disgusted with no accountability by the politicians and government who should be regulating this !