Endoxifen and CYP2D6 test
Hi,
i’ve been reading posts for a few months since being diagnosed with early breast cancer in early November. I really appreciate posts people make - it’s been a comfort to come and on and read the real deal. I continue to be blown away by how little I understood breast cancer and its ongoing impacts before getting it myself. I’m sorry that we are on this cancer path, but I appreciate the group support.
I’m hormone receptor positive/her2 negative and have had sentinel node biopsy, lumpectomy and radiotherapy. I was fortunate enough to be able to get the OncotypeDX test, which showed chemotherapy would only give 1% benefit. Prior to test results, my oncologist was strongly recommending chemo. I’m about to start tamoxifen.
I usually take really low doses of medications, way below the standard dose, for anything to do with pain, migraine, or low blood pressure. A doctor has suggested that I am a slow metaboliser for drugs processed through the liver, but I don’t really understand what that comment means.
In looking at tamoxifen, it is metabolised by the liver (best I can tell), into endoxifen which seems to be its “active ingredient”.
Sorry if I’m repeating a question, but has anyone ever looked into testing for CYP2D6 which is the gene (I think that’s what it is) that metabolises tamoxifen. I read some articles that say it’s all inconclusive, and others suggesting that testing is useful, as if you are a poor metaboliser, then need to look at using aromatise inhibitors earlier (with ovary function suppression?). Testing is offered but not sure if it is bunkum. Here’s one link where the test is described: https://www.dhm.com.au/media/21900626/pharmacogenomics_brochure_2013_web.pdf
Any thoughts? (Even if it’s just that I’m overthinking it!)
Thanks, and warm thoughts to folk out there for a good night’s sleep tonight
i’ve been reading posts for a few months since being diagnosed with early breast cancer in early November. I really appreciate posts people make - it’s been a comfort to come and on and read the real deal. I continue to be blown away by how little I understood breast cancer and its ongoing impacts before getting it myself. I’m sorry that we are on this cancer path, but I appreciate the group support.
I’m hormone receptor positive/her2 negative and have had sentinel node biopsy, lumpectomy and radiotherapy. I was fortunate enough to be able to get the OncotypeDX test, which showed chemotherapy would only give 1% benefit. Prior to test results, my oncologist was strongly recommending chemo. I’m about to start tamoxifen.
I usually take really low doses of medications, way below the standard dose, for anything to do with pain, migraine, or low blood pressure. A doctor has suggested that I am a slow metaboliser for drugs processed through the liver, but I don’t really understand what that comment means.
In looking at tamoxifen, it is metabolised by the liver (best I can tell), into endoxifen which seems to be its “active ingredient”.
Sorry if I’m repeating a question, but has anyone ever looked into testing for CYP2D6 which is the gene (I think that’s what it is) that metabolises tamoxifen. I read some articles that say it’s all inconclusive, and others suggesting that testing is useful, as if you are a poor metaboliser, then need to look at using aromatise inhibitors earlier (with ovary function suppression?). Testing is offered but not sure if it is bunkum. Here’s one link where the test is described: https://www.dhm.com.au/media/21900626/pharmacogenomics_brochure_2013_web.pdf
Any thoughts? (Even if it’s just that I’m overthinking it!)
Thanks, and warm thoughts to folk out there for a good night’s sleep tonight
