This may be a silly question re: arimidex...

jacksnana

I know about the risk of bone loss while taking Arimidex - but is it the drug itself that causes the possible bone loss or is it the lack of estrogen (which is arimidex doing its job!)?  Pretty sure it is the lack of estrogen, but is that what also causes the other side effects, i.e. high cholesterol? 

My PCP and my oncologist agree that I don't need another dexa scan until I've been on arimidex for two years, even though I had osteopenia before starting.  The two year mark will be coming around in a few months and I'm already stressing about it.  Thanks in advance for your replies.

SpecialK

jacksnana - I think it is the loss of estrogen because bone health and control of cholesterol are reasons ob/gyn will recommend HRT after a hysterectomy if you are not yet menopausal.

cycle-path

I don't think the way in which Arimidex causes bone loss is really understood. Tamoxifen also supresses estrogen, but it actually REDUCES your risk of bone loss. So apparently it's not a simple case of one's estrogen being suppressed.

Once you've been diagnosed as osteopenic, you should have a DEXA scan every two years, period. IMO it's very irresponsible for your doctors to say otherwise! What possible reason could there be for not following the accepted guidelines?  

otter

jacksnana, I think you're right.  Arimidex and the other AI's basically turn off estrogen synthesis.  They inhibit "aromatase" so effectively that estrogen levels become almost undetectable.  Lack of estrogen can cause most of the things we associate with AI's, like bone loss, high cholesterol, vaginal dryness/atropy, etc.

Tamoxifen acts totally differently.  It does not suppress estrogen synthesis at all.  In fact, estrogen levels in a woman on tamoxifen may be higher than in women who are not taking tamoxifen.  (We're discussing that in a different thread, and I don't know where things stand there.)

Tamoxifen is a "selective estrogen receptor modulator" (SERM).  Tamoxifen binds to estrogen receptors and blocks the abiliity of the real estrogen molecule to attach to the receptors.  But, tamoxifen is a receptor "modulator" -- not just a receptor blocker.  That's because when tamoxifen binds to some types of receptors (or receptors on some types of cells), it actually stimulates those cells through the receptor, as if estrogen was binding there.  Whatever those cells would have done in the presence of estrogen, they do in the presence of tamoxifen.

That's not what we want our breast cancer cells to do, of course.  Fortunately, when tamoxifen binds to a breast cancer cell, it serves as an estrogen receptor "antagonist" -- it blocks the action of estrogen on that cell and doesn't mimic estrogen either. 

But, when tamoxifen binds to uterine tissue, it stimulates the uterine cells as if it was estrogen.  That's why there is a risk of uterine cancer in women taking tamoxifen.  And, IIRC, tamoxifen promotes bone strengthening in much the same way estrogen would, because it stimulates bone cells to make more bone (or destroy less bone, depending on the type of cell).

[ETA:  I forgot to offer this link, which is a page in the educational section of BCO that discusses "SERMs":  http://www.breastcancer.org/treatment/hormonal/serms/ ]

Your question isn't silly at all.  BTW, you said your PCP and onc had you wait 2 years before repeating your DEXA scan.  Mine did, too.  Even the bone specialist to whom my med onco referrred me said every two years was often enough, despite the fact that I was osteopenic on a baseline DEXA done when I was starting on Arimidex.  My bone density had not changed at my repeat DEXA 2 years later (I had not progressed to osteoporosis).

otter

cycle-path

Excellent info, otter, thanks for posting!

I believe jacksnana said that she's due for her next DEXA scan in a few months, meaning that she apparently had one in (about) January of 2010. Yet her doctors are saying she shouldn't have another DEXA until she's been on Arimidex for two years. 

jacksnana

Thanks so much for your posts - I always get such better info here than from any of my docs!!    Otter, you always explain everything so clearly.  I hope my results are like yours, with very little change!

I've been having DEXA scans every two years - the last one right before starting Arimidex, so then I'll have one again two years from that date (April or May, just starting my stressing early!).  Guess I was thinking I should have one every year while on Arimidex, but they both agreed two years.  Thanks again, everyone.

cycle-path

BTW, you might want to read this thread. I couldn't find it earlier.

http://community.breastcancer.org/forum/78/topic/775243?page=7#idx_189 

jacksnana

Thanks cycle-path.  I found the thread and read the last page and will read the entire thread tonight when I have more time. I've always been really afraid of going on a bisphosphenate due to the fact that I've had tons of dental work done, so hoping and praying that I won't have to.  Thanks again for finding this thread for me.  Veda

ruthbru

I do a DEXA every year. If something is going on there, I want to know right away. Walking, running, dancing etc. any exercise where you pound your bones (not swimming) will help with bone density. Also lifting weights. Consume food with lots of calcium and/or take suppliments,of course, and also eat PRUNES.....a serving a day.

jacksnana

Doing all I know to help keep my bones healthy, supplements, try to stick to somewhat of an alkaline diet, eating prunes everyday, no caffeine or sodas, etc., so I sure hope it is paying off.  I'm sure my anxiety and worrying about anything medically related doesn't help anything so if I could get that under control... 

JO, it's encouraging to hear that for you everything is getting back to where it should be after finishing Arimidex.  Thanks everybody for your comments!

Fearless_One

Your docs say two years because that is how often insurance covers it in women who have not had BC.   My insurance paid more frequently than that.   You may wish to ask your oncs if this is an insurance issue.   IMO, you should have a DEXA every year while on an AI.

otter

(Stop me if I've already said this.  I tend to forget sometimes.) 

I have an "osteoporosis doc" -- an endocrinologist at my cancer center who specializes in bone problems.  She is monitoring my bone density. 

My med onc ordered my first DEXA scan, which was done to establish a baseline when I was starting Arimidex.  When the results indicated I was borderline osteopenic, she tested me for other causes of bone loss; and it turned out that I was excreting too much calcium in my urine.  That had been a part of my documented medical history for many years, but everybody had been ignoring it.  So my med onco referred me to the osteoporosis doc, and she put me on a drug that keeps the calcium excretion within normal limts.

I had my next DEXA scan in 2010, and it showed my bone density had not changed (still borderline osteopenic).  The osteoporosis doc and I discussed annual DEXA scans at that time.  She said they really weren't useful, because 1) there is a lot of scan-to-scan variation anyway (the procedure is subjective); and 2) it usually takes more than one year to see clinically relevant changes (i.e., the benefit from the drug she'd put me on wouldn't be detectable after just one year).  But, as an experiment, she requested insurance approval for a follow-up DEXA scan one year after the 2010 scan. She predicted that it would be denied, but she added that a denial didn't worry her because I really didn't need one until the next 2-year mark anyway.

The one-year DEXA scan was denied by my insurance company.  I have very good insurance coverage -- they didn't hesitate when asked to pay for my Oncotype DX test, my BRCA testing (even though I was low risk for a mutation), or even a screening MRI when I told my BS I was nervous about breast density.  I was sent a copy of the denial letter.  It included 5 or 6 pages of logical, documented reasoning why it was not helpful to have a repeat scan after just one year. 

Basically, their argument was that there is no evidence in the medical literature of a clinical benefit of annual DEXA scans in women with my risk factors for osteoporosis.  Annual scanning is covered by my policy if there are other factors that result in higher risk or in women that already have osteoporosis.  I think maybe having stable bone density (albeit borderline osteopenic) after 2 years of Arimidex might have been a part of the equation.

So, you are correct -- insurance coverage was the determining factor for me; but neither my med onco nor my osteoporosis doc think I need annual DEXA scans.  YMMV, though; and, obviously, different docs and different insurance companies have different opinions.

otter

jacksnana

Thanks, Otter.  I was more than just borderline osteopenic in some places, I think, but not yet to osteoporosis level.  I asked about going to an osteoporosis clinic but my gyno didn't think it was necessary yet, even given that I am on Arimidex.  Both my PCP and oncologist said that DEXA scans every year would show such little change, so I just relied on what they told me.  I'll be seeing my onco at the end of the month so we'll talk about it again.  I had a hysterectomy over 20 years ago and have been having DEXA scans for 10 years.  I had been on HRT but the last 5 years or so it was a tiny, tiny dosage and that's when most of the bone loss had occured.  I just hope it has stabalized, in spite of being on Arimidex, and that the exercise, supplements and dietary changes help.  So scary to me.

Annabella58

This is a great thread for info!  Hi Otter!  Thank you for your insightful and useful info, I am in your same shoes re: diagnosis (but not HER2N), and the borderline oesteopenia.

My GP has told me that osteopenia by no means always progresses to osteoporosis, esp. if you are small (check) caucasian (check) and small boned (check).  It can just mean that you have small bones.

She said every two even three years is just fine.  I've had an ooparectomy, a hysterectomy and am on arimidex, so prob. time for me.  I have the excess extretion of calcium as well.

**Just an aside...Total is great, but you can't absorb calcium in more than 500 mg. at a time, so you'd need to eat it twice as you cannot get 1,000 mg. at once.  All that calcium can build up in your bloodstream, so you want to space it out a bit.

Wren44

My oncologist wants me to take arimidex and I'm very concerned. I have osteopenia (dx 3 yrs ago) and he's going to another DEXA before I begin the drug. My mother and grandmother both had osteoporosis and congestive heart failure. I'm taking a statin for cholesterol and 3 blood pressure meds. I'm 71 and had a complete hysterectomy in 2000. I'm going to ask him to check my estrogen level before I decide, hoping it will be low enough that I won't need the AI. I'm really nervous about taking a drug which may worsen conditions I already have. Taking the AI would reduce my risk from 14% to 7%. My bc was small and early and I'm wondering if 5 years of arimidex would be overkill.

peggy_j

Wren, some post-meno women choose to take tamoxifen. The AIs are newer drugs so years ago tamox was the only drug. Your MO should be able to discuss the pros and cons . And even though the docs keep saying five years, you may choose to take a drug for a shorter period of time. When I researched tamox I found several studies on PubMed. Five years of tamox does the most to reduce the risk of recurrence but 2 or 3 is better than none. (some of the risks associated with tamox, like clots, increase after a few years) The five years isn't magic but a general risk/reward threshold. After 5 years the benefits drop while the risks go up. But everyone is different and we might decide to take a drug for fewer years.