Question for Al from Canada

Rozebud made mention in a post on 6/23 on Tamoxafin and Aromatose that there was anecdotal evidence that tamoxafin and herceptin were not good to take together. She said you had commented on it and I have searched and been unable to find anything.
I am scheduled to receive my first herceptin treatment on July 12 and will also begin taking tamoxafin at that time. I was diagnosed with three cancers in one breast. One of them Her2+++ and ER/PR- and the other two Her2- and ER/PR +. I want to take something for all of them but am now concerned about the interaction between the two drugs. I'm 52 and was perimenopausal at the time of my dx so ovary suppression and an AI is an option.
Thank you for any help you can offer.

Peggy

Dear Peggy,
Here is a great and comprehensive article on the whole HER2 vs ER+ thing. If there is some you don't understand, I will try my best to simplify it.
Regards,
Al

The link: http://annonc.oxfordjournals.org/cgi...ull/14/12/1697

What was the conclusion of the anastrazole (ie: Arimidex) and Herceptin? I assumed that this was the way to go over Taxoxifen. My rationale had always been to reduce steric inhibition of the receptor sites (ie: let the Herceptin find the HER 2 receptors on the cell surface. This can be done more easily if Taxoxifen is not associated with the cell surface (so the Herceptin can bind better - only one alignment so everything "fits" on the surface)). Then inhibit estrogen production with an AI. Biochemically, I felt this is the way to go.

Is this what this article is inferring? (I have an MS in Biochemistry so I understand the mechanisms behind this article and the studies).

Let me know your thoughts or where I can find additional info. I just started Herceptin as an adjuvant 2 weeks ago (I am 4 months out of chemotherapy). I would not allow my onco to put me on tamoxifen and insisted on LH/FSH tests to prove I turned postmenopausal (I was but will get this retested every two months as I was not prior to chemo. I am 46). So I am on Arimidex now and I theorize, that this with Herceptin is the best possible combination. I am toying with getting the ovaries removed to insure I stay postmenopausal.

Thanks for being here. This is the best site ever.

Becky

Hi Becky,

The verdict is in about Herceptin (H) + Tamoxifen (T), that is, HER2+ make the cancer resistant to T therapy and when combined with H it actually causes disease proliferation. The question about AI's is a different one. One study has shown that AI's in HER2 BC has a Time to treatment failure (TTF) of 5.6 mos where the TTF of AI's in HER-(-) BC was 11.6 months. This still suggests that there is some x-talk between HER2 and the AI mechanisms.

On the other hand, there is a study quoted in this article where the end point is a 33% reduction in Time to progression for H + Letrozole (an AI) vs Letrozole olone.

I think in his closing arguments, the author is suggesting that in HER2+/ER+ BC; AI's alone is sub-optimal and the way of the future will be H+ AI's To Quote: "....suggest that combining treatments that target these different pathways may provide additional clinical benefits for patients with breast cancer." and, "together the evidence suggests that targeted non-chemotherapeutic combinations of trastuzumab with hormonal therapy, which are currently being studied in large-scale clinical trials, represent the future of cancer therapy, allowing the individualisation of treatment based on tumour characteristics."

Keep in mind that this is one man's view and the jury is still out! Under no circumstances would I try to co-medicate with any type of Chemo and AI's.

Confusingly yours,
Al

Thank you Al. I am not mixing chemo and AIs. I have been done with chemo (dense dose 4 AC followed by 4 Taxol in early Feb). Had 7 weeks of rads (ended mid April) and started Arimidex about 6 weeks ago. Started Herceptin as an adjuvant (due to the trial results) on June 17 (will have my third weekly treatment this Friday to continue for a total of 52 treatments (unless the HERA 2 year results justify longer)).

Therefore, I am assuming the Arimidex/Herceptin combo is the right thing to do right now. My oncologist (as well as a second opinion from Sloan Kettering) were set on Tamoxifen which I rejected outright. They wanted me on it for 1-2 years and then switch. I said no way.

Is there any evidence that the AI should not be used? I have not found any evidence. All fingers point to this AI/Herceptin combo (especially in the adjuvant setting).

Thanks for your help and insight.

Best regards,

Becky

Thank you Al and Becky for you responses. I am a plumber not a chemist or biologists so reading through some of the studies can be a daunting task.
I saw my onc yesterday. She recommended tamoxifin but agreed on arimidex. She said she thought arimidex "tweeked" things in my favor slightly, but thought it wasn't worth Lupron shots or surgery. I think that it is and she agreed to do what I want.
I start herceptin on July 12th, 4 weeks out from my last chemo.
Again, thanks for the help.
Peggy

Peggy,

Another success story on "how to bring your onc around".

Great stuff!!!

Al