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Debbie L. · 10-18-2011, 01:19 PM

Hi Pray.

The answer to your question depends upon what exactly you mean by "working". If you mean is it keeping estrogen levels low in your blood -- yes, that can be tested although I've heard it said that the low end of the estrogen curve is hard to test for (the low end being anything below "normal" menopausal levels).

If you mean is it "working" as in guaranteed to keep cancer at bay -- alas, there's no way to know that for any one individual, and that includes those whose estrogen levels are successfully suppressed. We know what percentage of a big group it seems to "work" for -- but have no way to know who will be in which group ahead of time. So we have individualized and/or targeted treatment with Arimidex, but wouldn't it be even nicer if we could dial it down closer.

I asked you this in some other thread, I think. I've never heard of a test that tells whether Tamoxifen is working. There was interest in an enzyme called CYP2D6 for awhile, because in theory it is involved in the metabolism of some drugs, including Tamoxifen, and it was speculated that those with variations in the CYP2D6 gene would not benefit from Tamoxifen. But that has apparently been proven to be a wrong theory, to the satisfaction of practicing oncologists -- and is no longer considered an appropriate test. It never WAS an officially-recommended test but some oncs jumped on the bandwagon a little early on that one and did do the test and use it to prescribe (or not) Tamoxifen, for awhile. Is that the test you had? Here's Susan Love's page from January of this year on this subject:
http://www.dslrf.org/breastcancer/co...d=132&cid=1146

She actually leaves a little more wiggle-room for further studies to look at this again. Most oncologists I've heard discuss this are not even interested anymore, considering it a done (dead) deal.

Debbie Laxague

10-18-2011, 01:19 PM	#9
Debbie L. Senior Member Join Date: Jul 2006 Posts: 463	Re: Does anyone know of a test that... Hi Pray. The answer to your question depends upon what exactly you mean by "working". If you mean is it keeping estrogen levels low in your blood -- yes, that can be tested although I've heard it said that the low end of the estrogen curve is hard to test for (the low end being anything below "normal" menopausal levels). If you mean is it "working" as in guaranteed to keep cancer at bay -- alas, there's no way to know that for any one individual, and that includes those whose estrogen levels are successfully suppressed. We know what percentage of a big group it seems to "work" for -- but have no way to know who will be in which group ahead of time. So we have individualized and/or targeted treatment with Arimidex, but wouldn't it be even nicer if we could dial it down closer. I asked you this in some other thread, I think. I've never heard of a test that tells whether Tamoxifen is working. There was interest in an enzyme called CYP2D6 for awhile, because in theory it is involved in the metabolism of some drugs, including Tamoxifen, and it was speculated that those with variations in the CYP2D6 gene would not benefit from Tamoxifen. But that has apparently been proven to be a wrong theory, to the satisfaction of practicing oncologists -- and is no longer considered an appropriate test. It never WAS an officially-recommended test but some oncs jumped on the bandwagon a little early on that one and did do the test and use it to prescribe (or not) Tamoxifen, for awhile. Is that the test you had? Here's Susan Love's page from January of this year on this subject: http://www.dslrf.org/breastcancer/co...d=132&cid=1146 She actually leaves a little more wiggle-room for further studies to look at this again. Most oncologists I've heard discuss this are not even interested anymore, considering it a done (dead) deal. Debbie Laxague