Tamoxitest? Anyone have it? Is it necessary?

horsegal13 · January 2010

I am to start on Tamox on Jan 11. My friend who had breast cancer last year and had a mastectomy and reconstruction told me she could not take Tamox cuz she had her ovaries, and they tested and she would not respond to Tamox, something because of her estrogen. So she had to have her ovaries removed first, now she is on Tamox. I called my oncologist, but he is out of the office until Jan. 11, I want to know if I should ask for one or if it's necessary. I had a hysterectomy last fall, but kept my ovaries. I'm hoping they call me back before my appointment.

otter · January 2010

horsegal, I think the "Tamoxitest" is a genetic test that measures whether you produce the enzyme (CYP2D6) that's needed to metabolize tamoxifen into its active form. Here's a website that talks about the test: http://www.tamoxitest.com/

If someone's Tamoxitest result shows that she "does not respond to tamoxifen," I can't see how taking out the ovaries will make her responsive to tamoxifen. Removal of the ovaries will decrease the amount of estrogen in the body if the ovaries are still making estrogen, but the surgery will not change whether or not tamoxifen can be converted to its active form.

There are several threads on the boards that discuss CYP2D6 testing. One is on the first page of the "Hormonal Therapy" forum; it's called "Most Drs only order CYP2D6 testing if the patient asks." Tamoxitest is one company's version of the test; toward the end of that thread are some posts providing the names of other companies and labs that also offer it.

If I were considering taking tamoxifen (I'm not -- I'm postmenopausal, and on Arimidex), I would not hesitate to ask my onco to test me for the CYP2D6 alleles. I think I would pay for it out of pocket if my insurance didn't cover it. There's just no sense in taking an anti-cancer drug, even one as cheap as tamoxifen (a generic), if you don't even know whether it can be coverted to an active form in your body. IMHO, anyway.

otter

lexislove · January 2010

Hi horsegal,

I have been on Tamox for 18 months and just ordered the test otter was discussing. I got the test from the same company, and paid $300.00. Out of pocket, but very necessary. Still waiting for the results.

Most woman do metabolize Tamoxifen fine. I think its 10% or less of the population that does not, and should then have their ovaries removed and take another anti hormone. Ovaries are only removed if the woman is pre menopausal.

Even though, my chances of metabolizing Tamoxifen are good, I cant take that chance that I do not, and might be compromising my survival. You just never know.

Good luck.

NativeMainer · January 2010

tamoxifen is an inert chemical that the body, through the CYP2D6 enzyme system is metabolized to endoxifen, which binds with estrogen receptors and block their function. This prevents ER+ bc cells from getting the message to multiply. A woman who does not metabloize tamoxifen gets no protection from it. Theses women can have ovarian suppression --turning off the ovaries with medication like lupron injections, surgical removal, or killed by radiation. After menopause, when the ovaries stop making estrogen, some estrogen is made in the fat cells. An enzyme called "aromatase) transforms cholesterol and similar substances to estrogen. The AI's are Aromatase Inhibitors--these drugs (arimedix, faslodex, etc) stop this enzyme from working, so no estrogen is produced in the woman's body (or very, very little is made). When there is no circulating estrogen, ER+ bc cells never get the signal to multiply and eventually die off.

When I was diagnosed the tamoxifen test cost $3000 and my insurance considered it experiemental. So I took tamoxifen for several months hoping it was working. Since I wasn't having one single side effect (that I knew of) I begged my med onc to change me over. Turns out I was metabolizing the tamox--I didn't realize how much worse my depression had gotten on it (tamox is known for depression as a side effect). I have hot flashes on arimidex, but that's a whole lot better than depression to the point of not getting out of bed for days at a time!

nene2059 · January 2010

I had the Cyp2d6 test at the urging of my health insurance..weird right? I was going to ask for it but decided to try the Tamox for a month and see if I has side effects first. a few weeks later my insurance called and said that they are participating in a study and had ok'ed it with my onc and I could take it free of charge if I wanted participate. I did and I was a poor metabolizer, in that 10% Ugh. Anyway like someone posted earlier I was given the option to surgically remove ovaries (oopherectomy), take Lupron shots to temporarily shut them down (like I did during chemo to PROTECT my fertility...hindsight is 20/20) or radiate them to shut them down. Only one I could see any real, long term benefit to was the ooph so I had it in September. I did that so I would become postmenopausal and could be put on an Aromatase Inhibitor like Femara, Arimidex, Aromasin, not so that I could take Tamoxifen. If you are a poor metabolizer removing the ovaries won't change that and Tamoxifen is not an option for you so I would check with your friend to make sure she is getting good info or understands what she is being told. It can be a lot to take in. I had two tumors and one was very estrogen positive so it was the right thing to do. Best of luck.

horsegal13 · January 2010

I think she is on a different med. I thought she was on Tamox, but her hubby told me she can't take it and they removed her ovaries. He didn't give me all the facts, you know men! haha

She is doing great though. I am definitely going to talk to my oncologist about the CYP2D6 test, thanks so much. I learn alot on here, haven't been here too long, but find alot of answers that sometimes even the doctors forget to mention to me.

Everlastpink · January 2010

I don't know if this is what happened with your friend, but here is my situation. I was pre-menopausal and a blood test my onco did showed I had a genetic tendency towards getting blood clots. Tamoxifen can increase blood clots, so since I was already 46 and heading towards menopause, all my docs decided to remove my ovaries so I could take Armidex, which is for post-menopausal women. Tamoxifen acts on the ovaries, arimidex acts on the adrenal glands and other fat tissues that produce estrogen. I did not have the test to see if I could metabolize tamoxifen, since they were worried about the blood clot side effect. I could have chosen to have monthly shots which suppress the ovaries, but for this reason (blood clots) and others (concern over ovarian cancer), I chose to have the ovaries removed.

Glad your friend is doing well. I am too, although menopause is not too fun!

horsegal13 · January 2010

I just talked to my oncologist's nurse, she told me that he does not do this test. She said to talk to him when I come in on Monday. I may have to insist on it, or switch doctors. We'll see what happens on Monday.

lexislove · January 2010

Update:

I received my results of my CY2PD6 test...................poor metabolizer. Great.

thank god I have been doing Lupron all this time in addition to Tamoxifen. Im meeting with my onc next week to talk about my options. Options being: 1) Lupron+ AI, 2) Ooph+AI

I was really hoping to hold out on the ooph + AI for as long as I could, but now it will probably happen sooner.

I did the test from Genelex(sp?). I question there reliability and accuracy. Maybe Im in denial...lol.

My onc did state briefly that just because Im a poor metabolizer, doesnt mean Im not receiving any benefit and that benefit is not working. He has no problem switching me to an AI, but thinks this test can be misleading....sigh

horsegal13 · January 2010

Here's some info I've been reading up on...........

Findings from a new study have prompted Mayo Clinic researchers to recommend CYP2D6 gene testing for postmenopausal women about to begin tamoxifen therapy. This data confirms that women with an inherited deficiency in the CYP2D6 gene, which is important for the metabolism of tamoxifen, have a nearly fourfold higher risk of early breast cancer recurrence compared to women who have not inherited the deficiency. The research findings, announced jointly by investigators from Mayo Clinic and the Austrian Breast and Colorectal Cancer Study Group (ABCSG) confirmed results from a previous study conducted by Mayo Clinic. Tamoxifen, approved by the Food and Drug Administration (FDA) to both prevent development of estrogen-receptor-positive (ER+) breast cancer and as a therapy to stop ER+ breast cancer from coming back, is a "pro-drug"; it must be metabolized in the liver to become active. Mayo researchers had previously discovered that the drug is less effective in postmenopausal breast cancer patients who had a deficiency in the CYP2D6 gene, which is key for activating tamoxifen and many other drugs. However, until now, testing for the gene has not been done routinely at most medical centers.

lexislove · January 2010

Ive read that too.

Im glad that they are finally saying that the test is worth while to get. So many oncs though are STILL not sure and sceptical.

Since I have been on Lupron for 18 months, am I considered menopausal even though Im only 32? My period stopped on AC back in December 2007. No period since.

Tamoxitest? Anyone have it? Is it necessary?

Comments

Categories