Oncotype DX & cyp2d6

scaredinnj

Oncotype DX & cyp2d6

scaredinnj

I have finished my six rounds of TAC and just started tamoxifen.  My onc. ran a CYP2d6 test and I am either a poor metabolizer or intermediate metabolizer.  I don't know for sure if I have started menopause as my last full period started prior to diagnosis and my mother had an early menopause as well.  My onc. said that I should switch from tamoxifen to arimidex if they can confirm that I have started menopause.  I also had an Oncotype DX test with a low recurrence score.  Everything I have read about CYP2D6 poor and intermediate metabolizers is that they have such a significantly higher recurrence rate.

 My question is how to reconcile the Oncotype DX score with the CYP2D6 test.  Does the Oncotype DX score include a test of the CYP2d6 metabolizer.

 Has anyone heard anything about this?

BarbaraA

scaredinnj, the Oncotype Dx test assumes you will do 5 years of Tamox or and AI. So the recurrance % is based on that.

voraciousreader

I think Scaredinnj is asking the same question that I posted at the Johns Hopkins Ask an Expert website and Lilly Shockney, RN replied on June 21, 2010 under the "Hormonal Therapy" thread.

What I think Scaredinnj and I wanted to know was whether or not the Oncotype DX recurrence score takes into account whether or not a person is a "poor" or "ultra rapid"  or anything in between, metabolizer of tamoxifen when they determine the score.

Here is MY question and what Shockney said:

Once again, thank you so much for taking the time to answer my questions. I just received the results of my CYP2DG screening test and found out that I am an ultra-rapid metabolizer of Tamoxifen. While the test is still controversial, my oncologist uses the test primarily to find patients that are poor metabolizers and then considers alternative treatments. Since I am an ultra-rapid metabolizer, he is comfortable with me taking Tamoxifen. Now, for my question. I got to thinking back to the Oncotype DX recurrence index which is based on taking Tamoxifen. What I'd like to know is wouldn't the recurrence score, not only be affected by the genetic makeup of the tumor and whether or not a person takes Tamoxifen, but ALSO on how well the patient metabolizes Tamoxifen? With all that we've learned about the CYP2DG test in these last few years shouldn't the Oncotype DX scores be adjusted for this variable? Furthermore, I've found that some drugs may interfere with Tamoxifen, making it less effective. Shouldn't this variable also have been considered when they came up with the recurrence score? My gut is telling me, even though the Oncotype DX test is a good tool in helping determine treatment, perhaps it is already antiquated for predictive measures. Your thoughts? Thank you!
Replied	JHU's Breast Center Reply
6/21/2010	I have mentioned the same issues you listed to folks involved with this previously done research. my recommendation was to revisit it or even do new research factoring in these additional test results since metabolism of the drug is key. don't know if that will be done or not but i've brought it to their attention in any case. glad you are a good metabolizer.

Member_of_the_Club

I really think very little is known about the CYP2D6 test so they aren't going to incorporate the findings.  There is some though that there are other pathways for metabolizing tamoxifen, so the results may not mean a whole lot.  

revkat

The thing is, early reports of cyp2d6 testing showed what researches had hypothesized -- that poor metabolizers had a poorer clinical outcome (more recurrences). HOWEVER, as the sample group got larger, the effect disappeared. So, what does that mean? Clinically, based on the largest, latest study sample, there doesn't seem to be a correlation between cyp2d6 status and how well tamoxifen works for you. So now researchers are looking at what other pathways may be used to metabolize the tamoxifen, and wondering if the endoxifen (what they thought was the active metabolite of tamoxifen) is even the critical factor in tamoxifen's success is prevent recurrences and increasing overall survival for the women who take it.

oceangirl654

I thought of your question too- whether the oncotype test includes the CYP2D6 genes and whether that's part of the results. I called them today and they said it doesn't. They referred me to this page, which tells about the genes that the oncotype test covers. I hope this helps! http://breast-cancer.oncotypedx.com/en-US/Professional-Invasive/WhatIsTheOncotypeDXBreastCancerTest/UnderlyingTechnology.aspx

roxyandtaze123

Hello,

I've never posted here but just want to share important information about Oncotype testing and my results with that test.

I was diagnosed with Stage I, ILC 12/2006 --Biopsy, Lumpectomy. Because tumor was against pectoral wall, I did not have clear margins and tumor was almost a .2 (can't remember all this detail but I'm trying). So the question was, do I do Chemotherapy. Did Oncotype testing -- which came back 11,,, No Chemo for me! Treatment then was Tomoxifin for next 5 years and 7 weeks off Radiation. I had to quit after 4 years due not complications with Endometrial Lining probs. I had had 4 D/C's. then got partial hysterectomy so I could go on Arimedex.

In August, 2014 I was having extreme pain in hip/pelvic area. The return of cancer in bones. Stage IV. My MO believes that a cell had gone hiding somewhere and when I started Arimedex, it came out and started to spread. My Oncotype results showed I had a 5 % chance of recurrence!!! Now I'm fighting for my life.

Just wanted everyone to be aware of this very costly test. It did me wrong, for sure. Not being negative, just want everyone to be cautious and ask many questions about this costly test.

Have a good week,

Bev