Tamoxifen or AI?

[kari]

In a couple of weeks, I will be seeing my onc for a three-month check up. I have been on tamoxifen for two years, and at that time we will be discussing whether or not to switch to an AI. I have been menopausal (chemo-induced?) since April '06. My question is, what are the risks/benefits of switching to an AI--specifically Exemestane (Aromasin)? I seem to be tolerating the Tamoxifen fairly well, the main side effects being hot flashes and mild nausea. Can anyone offer any thoughts/advice? I would prefer to stay on Tamox., providing it would be as effective as Aromasin.
I was peri-menopausal at age 46 when dx'd in Dec '05 with IDC, Stage T2N1, PR+/ER+/Her2+++. Treated with mastectomy, AC/Taxol chemo, local radiotherapy and Herceptin, then started Tamoxifen Nov '06.
Thanks for any input.

~Karen~

[Becky]

If you decide to switch to an AI make sure your onc runs a blood test on FSH, LH and estradiol to ensure you are in true menopause. Sometimes the FSH and LH are in the postmenopausal range but estradiol is not (but is too low for you to ovulate and menstrate) and that may actually get "fixed" by taking an AI and suddenly, you are menstrating again and because of low (but not low enough) estrogen levels, you were never protected by the AI due to ovarian estrogen production.

Otherwise, you will need Lupron or Zoladex shots to take the AI (or an ooph).

[dlaxague]

Karen, I agree with Becky that it's a huge gray area of menopausal-or-not and with an AI that is crucial information. However, it is not that easy to figure out. Hormone levels fluctuate quite amazingly from day-to-day and most of the experts that I've been listening to have been burned so many times, even when relying on two or three sets of blood tests, that they are quite wary of prescribing AI's to someone who is not clearly menopausal (has been without periods for two years before chemo, etc). It seems to me that they favor ovarian suppression with an AI if there is any doubt (and there is almost always doubt, in your 40's and even for some in theit 50's). And as we know from other recent threads, there is no evidence yet that ovarian suppression and AI is the same as menopause and an AI, although it seems logical.

Another interesting result recently, somewhat overshadowed by the zoledronic acid news from the same study, is that they are seeing no difference at all in that study between Tamoxifen and the AI, given to premenopausal women who are also suppressing their ovaries. Which is of course a surprise as logic would suggest they'd get the same results as the postmenopausal T vs AI studies. So many shades of gray, and of course we don't want to make any decisions based on just one study. But still, it raises interesting questions (as if we need more questions, arggg).

I thought that one of the most interesting things at SABCS last year was the question of whether Tamoxifen might not be just as good as an AI for those who metabolize it properly. A guess was hazarded in one of the Q&A sessions that if they were able to take the nonmetabolizers of T out of the stats in studies that compare Tamoxifen to an AI, the increased benefit from an AI might disappear. I cannot remember who said this but it was one of the big names (Winer, Allred, ...?).

This is not helping much with your decision. But since you're liking the idea of sticking with Tamoxifen, maybe it would be worth waiting until after SABCS (12/11-14) to make a final decision, in case there's new evidence either way.

When they first began looking at AI's, there was discussion that an AI seemed to be better overall but especially for HER2+ cancers, while Tamoxifen often met with resistance in same. As I understand it, since then, they do not still think that, especially in the presence of Herceptin. It seems to be more that HER2+ cancers are more likely to be somewhat resistant to hormonal treatment in general. Whether that is simply because they also tend to have lower levels of receptor positivity or if there are other things going on in addition does not seem to be clear yet.

When there is a decision to be made and no clear answer(s) upon which to make that decision, I advise trusting your intuition, or gut, or still small voice - I know that will be the right decision, for you.

Debbie Laxague

[TSund]

Karen, do you know why your dr is recommending aromasin over femara or arimidex?

Debbie,

Thanks for the informative post. Things are that much more confusing for those on the "cusp" of menopause.

I think I posted on this website my speculation about the tamoxifen metabolizers and the study stats.

Are there any minuses perceived about having an ooph? I always thought it sounded like a pretty good idea, but two doctors have discouraged it in Ruth's case.

We also have the situation of "changing PR status" of the original biopsy vs the post chemo/surgery one.

What are the longest term Tamoxifen vs AI studies available? I wonder if the stats will change in those crucial post ER treatment years. (crucial for those with ER+ bc)

TRS

TRS

[dlaxague]

Are there any minuses perceived about having an ooph? I always thought it sounded like a pretty good idea, but two doctors have discouraged it in Ruth's case.

Hmm. From a purely breast cancer perspective I don't think that there are minuses other than the risk associated with any minor surgery. But for young women, we don't know much about the long term effects of such drastic estrogen suppression as is achieved with oophorectomy and AI's. Again, more questions than answers right now. There was a study reported a year or so ago about increased dementia when young women had ooporectomy (I don't think that it was a breast cancer-related study). I talked to some young women then whose reaction to that study was relief that they were using ovarian suppression rather than ooph. But who's to say they wouldn't have seen the same results either way? And again, we can't hang our hats on one study.

What are the longest term Tamoxifen vs AI studies available? I wonder if the stats will change in those crucial post ER treatment years. (crucial for those with ER+ bc)

Good question. I don't know. I think ATAC and MA17 are the main ones (adjuvant AI vs. T) - it's frustrating to search and keep getting links that require membership or payment. There are so many studies - T vs. AI right off, T for a few years and then AI vs. AI only. AI after T at 5 years. And in the podcasts I've been listening to, some have suggested that they are intrigued with the idea of alternating back and forth, or even having holidays of nothing between alternating. It would be nice if someone could tie it all up neatly for us in a summary of what we know. I don't think any of the questions are (yet) answered for sure. Which one? Which sequence, if sequenced? And especially - for how long?

I guess the good news here is that if one particular way was clearly much much better, we'd know that by now. So the fact that we're niggling with all these different scenarios probably does mean that the differences between regimens are fairly small and thus the decisions made are not that critical? That's easy to say in the global perspective but much harder to achieve nonchalance about for any one individual.

Debbie

[TSund]

Hi Debbie,

...and it is even more frustrating when one does not know how tamoxifen "non-metabizers" work into these numbers. I cannot understand why all studies would not do this blood test and either exclude them or publish it as part of the results.

Debbie, I asked this question elsewhere, but Donna said she had uterine thickening as a result of the arimidex. I had thought that only tamoxifen had that as a side effect. Do you happen to know if this is an established side effect of the AI's?

And, I wonder if there is a difference among the AI's if so.

TRS