Tamoxifen: 10mg vs 20mg

wenweb

Coraleliz- It's my understanding the the more weight you carry, the more fat your body has, and that's where estrogen is stored.  Makes sense to me and vise versa.

coraleliz

Wen-yes it makes sense to a certain extent. The medication isn't prescibe based on weight. It's entirely possible that our heavier sisters could benefit from a dose higher than 20mg. I read this somewhere, just can't find it.

Mopsy

Yes, I also read about more weight meaning more estrogen risk.  So who can say if heavier women should take more or lighter women should take less?  Apparently that has not been a high priority for study.

MO did say that Tamox used to be prescribed as 10mg/ 2x/ day and had no effect compared to 20mg/once a day, so they go with once a day for convenience.

I weigh 106, and so I wonder if the way Tamox works is based on weight or something else.  But I have developed left hip pain that I never had before, hot flashes (no sweating), and only occasionally a little of that "listing the right" feeling, but I do feel so tired.  So I am going to try 10mg for a while.  

If the SEs don't improve, then doesn't that mean that 10mg dose is still blocking the estrogen?

terrikoala

I am sure that my MO is not going to be pleased  at my next visit that I want to cut my dosage in half but you know what?  I  was fearful of taking  AT ALL and  took 3 visits for him to convince me. My bone and GYN health has always been really good and I sure don't want to add those issues after having the cancer experience. I am going to exercise my 66 year old perogative and  take half does regardless of what he says.  The sweating is worse than ever and I have 8-10 episodes in a 24 hr period these days.

Terri

Mopsy

I have been taking a half dose for a bit over a month now.  I never skip a day.  It took about 2 weeks to go from 2 hot flashes every hour to about 6-8 a day.  I can live with that.  I plan to go back to 20mg in October, though I will try half in the morning and half at night to see if that helps.

terrikoala

Mopsy,

Thanks for that report. I see the MO in a few weeks so I am going to cut dose to 10mg starting today and see what happens between now and then. I am thankful that so far I have not had any of the joint pain that many seem to have with the Tamox but this profuse sweating is getting out of hand and it makes my underarms 'stink'  and of course that makes my clothes smell and I have never had that issue before. Its nasty and no matter what deo or how much I use there is no change. I am very self conscious about it. I shower and after first sweat session I stink.

 

coraleliz

When my MO reduced my dose to 10mg, he had me stop taking it for 1 week. Tamoxifen has a half life of 10-14days so it lingers in the body. I started the lower dose after being of Tamoxifen for a week. I'm back to 20mg.

terrikoala

coraleliz...

Thanks for that information...good to know about the half life

new_direction

ive been on tamoxifen 20 mg for about half a year. Ive had joint pain and hot flashes but it has started to diminish. I was worried it was because the drug was less effective but my doctor said it was just my body getting used to the drug. So for some of you that may be having terrible SE they might go away after a while... Is anyone taking 40 mg? I was told i need to take 40 mg if my periods return.

new_direction

Ive just found an article stating there was no difference in outcome of Tamoxifen dosage 20 vs 40 mg. It's not as if there are plenty of studies. I would love to know more about this.

It doesnt seem like there are any increase in side effects though.

ata

Hello there, I hope that you all are doing well.

I found an article about the dosage and the effectiveness of Tamoxifen of 1mg, 5 mg and 20 mg.

https://academic.oup.com/jnci/article/95/11/766/2520250/Is-Low-Dose-Tamoxifen-Useful-for-the-Treatment-and

Actually I got a green light from my doctor to use 5 mg a day and I am 170 pounds.

Wishing you all the best.

Anonymous

Hello everyone. I hope your all fine. I am new to this tamoxifen thread and please pardon me for butting in but i just want to ask some questions and hope someone here might have the answers.

I had a right BMX last Sept. 21, 2016 and I just finished my chemotherapy treatment last February 22, 2017. My actual hormonal assay is only 5% ER, 3% PR and HER2 negative hence, I consider myself a Triple Negative cancer patient.

Yesterday, i was cleared by my MO after seeing my follow up PET scan and blood test results, although she pointed out that I have a left breast parenchyma (which is even older than my right breast cancer tumor) which stayed the same in size at .7cm even after the chemo treatment. My MO said that since I am actually ER/PR positive, eventhough weak, I still have to take Tamoxifen 20mg daily for 300 days and she already gave me a prescription for it right after my last chemo session. However, I delayed taking the Tamoxifen until I got my PET scan and blood tests results which turned out to be both clear.

My question Is if it is really necessary and correct for me to take the Tamoxifen 20mg pills?

and ...

If my old left breast parenchyma stayed the same in size after my chemo treatment, should it be considered benign as it was diagnosed before?

Please help.

Thank you all for this chance to ask my questions and may the Good Lord be with us all.

Warmest Regards,

Gina

BarredOwl

Hi gmmiph:

You may be interested in this guideline, which uses 1% positivity (as defined) as the cut-off for recommending endocrine therapy:

Hammond (2010): "American Society of Clinical Oncology/College of American Pathologists Guideline Recommendations for Immunohistochemical Testing of Estrogen and Progesterone Receptors in Breast Cancer"

http://ascopubs.org/doi/pdf/10.1200/JCO.2009.25.6529

PDF version available for free

If you are wondering about the recommendation you received, a second opinion may be helpful.

Regarding a reduced dosage, never alter the recommended drug dosage without consulting with your Medical Oncologist first. A key question that you should ask your MO is whether there are any clinical trials that have demonstrated the long-term safety and efficacy of the lower dose compared with the standard dose.

The reference cited by ata is an Editorial discussing several studies. Interestingly, they specifically note the results are not viewed as practice changing in the general case:

"A final question is whether the current study by Decensi et al. (11) is sufficiently compelling to change the standard practice of using 20 mg/day of tamoxifen for breast cancer treatment or risk reduction. Although the results reported by Decensi et al. (11) are provocative, in our opinion these studies should not alter current practice. Although Makris et al. (14) and Chang et al. (16) have demonstrated that a reduction in proliferation in the breast tissue correlates with clinical response, it is not yet clear whether the growth suppression induced by low-dose tamoxifen would produce the approximately 50% reduction in risk of recurrence or risk of primary breast cancer seen with tamoxifen at the standard dose. We agree with Decensi et al. (11) that the results provide strong rationale for future randomized trials of low-dose tamoxifen; however, their results should not overshadow the results of large-scale randomized clinical trials showing clinically significant benefit of tamoxifen at the 20-mg/day dose. So, is low-dose tamoxifen useful for the treatment and prevention of breast cancer? Possibly, but for now, clinicians should continue to use tamoxifen at the current standard dose of 20 mg/day."

BarredOwl

Casey4

The 10 mg. vs. 20 mg. debate has been in place since the Italian studies. (There are several). The problem is it is unlikely that a pharmaceutical company in the U.S. will undertake a clinical study on a generic drug to determine if the lower dose is effective. And non-profits/governmental/health care facilities usually take a "it's good enough" approach rather than working on refining use of what they consider to be an old drug.

Even my MO admits they have to prescribe 20 mg as that's the only clinical study they have; there could very well be different effective therapeutic levels for different people. Some doctors may tinker around with every-other-day dosing, or prescribing 10 mg pills to be taken twice daily (with a wink, wink, that you'll take only one a day) but as for a direct clinical trial, I don't think it will happen.

It is interesting, however, that the one clinical study that might be somewhat relevant is https://clinicaltrials.gov/ct2/show/NCT01196936?te...

which is studying low does (5mg) tamoxifen for reducing risk of radiation-induced breast cancer. While not necessarily analogous to all breast cancer I think the dosage is a nod to the possibility of low-dose risk reduction research. Notice this is sponsored by NCI and various hospitals.

I feel your frustration.

Casey

Anonymous

Hi BarredOwl,

Thank you very much for your reply and great info. That is the only info i got that makes sense. I really thought that I am to be considered a TNBC case because of my weak positive ER/PR status. I have been delayed from my scheduled start of taking Tamoxifen for a month and a half already because I was too afraid of its SEs.

My MO said there is no need for me to undergo radiotherapy but insists that i should take Tamoxifen, initially for 300 days at 20mg/day. Now that she cleared me from my PET scan and blood tests, i am a bit confused of how i should take the Tamoxifen based on the various experiences i read from the many threads here in this community forum. Now, I would prefer taking it at 10mg twice daily though.

I dont see much in you signature/profile. What is your pesonal experience with Tamoxifen? Are you also weak positive ER/PR? You seem to be doing fine since your dx in 2013. I wish you continued good health and a full happy life.

Thanks!

Hugs,

Gina

Michelle_in_cornland

Gina, I am on Tamoxifen and am doing terrific. Many women on these boards do just fine without any major side effects. I walk 5 miles a day, eat mostly a vegetarian diet, don't drink alcohol, and enjoy my life. When I started taking tamoxifen, I took 10mgs a day for two weeks, bumped it up to 10 mgs twice per day = 20mgs. I think the more positive you are about your situation, the better the outcome. There was a study and is on breastcancer.org that talks about this very thing. All of my answers are from personal experience, which is what we are supposed to be discussing on the hormonal forum. Don' let anyone scare you out of taking, or at least trying to take an antihormonal.

BarredOwl

Hi Gina:

One should always take a prescription drug as prescribed and according to instructions received (e.g., with or without food, etcetera). As far as trying a different dosage or twice daily dosing with half of the recommended dose, please ask your medical oncologist about it. Drugs have specific pharmacokinetic and pharmacodynamic profiles, and depending on the drug, a divided dose may or may not achieve the same thing as a single bolus dose (all at once).

As Michelle notes, many people find the side effects to be quite tolerable, but they do not post as often.

Did you have a mastectomy? Radiation therapy is not within the area of expertise of medical oncologists. The question of post-mastectomy radiation is a bit specialized, and in the US, a more case-specific approach is now being taken. Given one positive node, please consider requesting a referral to a Radiation Oncologist to confirm the advice of your MO and to ensure receipt of advice from a medical professional with the appropriate expertise.

My own situation is a little unusual. I had extensive bilateral DCIS, but with bilateral mastectomy, my medical oncologist did not recommend Tamoxifen for that. I also had a tiny 1.5 mm IDC and one < 1mm IDC, with negative nodes (0/4) on one side. Unfortunately, because they had to use several IHC stains to determine invasion, there was insufficient tissue to determine the ER or PR status of the small IDCs, and Tamoxifen was not recommended for them either. What led to consideration of Tamoxifen in my case was the presence of isolated tumor cells (pN0(i+)) on the side with pure DCIS. This could represent benign transport of cells following multiple biopsies (not a problem) or minimal nodal involvement due to some undetected or occult invasive disease (of unknown ER and PR status). They could not determine which was more likely, and again, they had no ER or PR status information. I received some rough estimates of distant recurrence risk with or without Tamoxifen, but the risk reduction benefit was small in my case, and not much higher than the low risk of severe adverse effects. My oncologist was very clear that it would be equally reasonable for me to accept or decline Tamoxifen, and after much thought, I declined it. In retrospect, a second opinion might have been helpful.

Keep in mind that the benefit of Tamoxifen is proportional to individual residual recurrence risk. Your medical oncologist can provide an estimate of your distant (metastatic) recurrence risk (after chemotherapy) either with or without Tamoxifen, which may help you understand the estimated risk reduction benefit in your particular case. (Tamoxifen can also reduce the risk of recurrent or new disease in remaining breast tissue.)

BarredOwl

codilaine

"Effects of low-dose tamoxifen on breast cancer biomarkers Ki-67, estrogen and progesterone receptors"

This was an interesting study regarding lower doses. The forum is telling me I can not post a link at this time, so just google the article.

Anonymous

gmmiph

I see that you have 2cm IDC and curious what they told you regarding no radiation? Have you had mastectomy? I have what they think is 1cm IDC and am told it will be necessary for me after lumpectomy. Will know more for sure after the surgery next week, but very interested in avoiding radiation if there's a good case to Beverly made for it.

I will be on tamoxifen and it looks like it will make a huge difference for me, so wondering if I can avoid the rads if I stick to the tamoxifen.

Siciliana

This may be a little off topic, I am wondering if the fact that I sailed through menopause without a single hot flash means that I will be more likely to have an easier time on tamoxifen. Does anyone know if there is a correlation between lack of menopausal hot flashes and lack of tam. related hot flashes? (My MO wants me to be on tamoxifen for a couple of years because I have mild osteoporosis and osteopenia and he thinks there's a good chance tamoxifen will increase bone density before switching to AI).

kira1234

Sicilliiana not sure the lack of hot flashes with menapause has any effect. I had horrible hot flashes with menapause but tamoxafin was a easy.

kira1234

Sicilliiana not sure the lack of hot flashes with menapause has any effect. I had horrible hot flashes with menapause but tamoxafin was easy.

ndgrrl

Hi, I was just put back on Tamoxifen , I had been on Tamoxifen but then a year after surgical menopause ( took dr a year to talk me into a diff med) I was put on Arimidex with horrible joint pain. then I was put on Femara and my fingers went numb as well as my bones are thinning- my Cholesterol and BP went up and so I am full circle in a year and am now back on Tamoxifen.

I now have a new MO and instead of the 20 MG once a day this new MO put me on 20 MG twice a day which confuses me. She never mentioned the dosage and after taking the meds three days I finally read the bottle and noticed way more pills in there and it says twice a day. HMMMM..

Anyone else on twice a day> Maybe cause I am now post menaupasal? Confused ....

coraleliz

ndgrrl-maybe it's a mistake by either the MO or the pharmacist.

runor

Just this morning I took my second Tamox tablet. I really, REALLY struggled over this. I think of all the things that have been done to me since this stupid cancer was found, I resent this intrusion the most. It has the potential to make me feel bad for a very long time.

These are my thoughts: Doctors don't know everything. When it comes to drugs, pharmacists know WAY more! Have a drug question, ask your pharmacist. Which I did. He said, due to the fact that cancer patients pick up their Tamoxifen at the hospital, he sells very little Tamox through his pharmacy so hears very little feedback about the drug. So I shuffled off to the ancient, creaking bowels of the hospital to the creepy little pharmacy where I had to ring a bell and a man opened a sliding trap door and shoved the Tamox at me. Weird.

Doctors read a book and if the book says, give your BC patient 20 mgs Tamox, then that is what the doctor does. MANY of our oncologists do what they do because it's what they've always done. I have never adhered to the almost reverent idea that I can't do anything without first consulting my doctor. And now with the badintenternet, we can do some research ourselves. Which I have done. To try and determine if a lower dose of Tamox will provide the same benefit as a higher dose. There is some work out there that looks promising to me. Nothing that will rock the medical world, but that can also be because the medical world, like everyone else, gets in a comfortable rut and stays there. It might be true that lower dose Tamox is just as effective, but it will take 50 years of beating the medical establishment over the head with this new reality to get them to change. So just because they have not adopted a new, lower dose DOES NOT MEAN that it is a bad idea. It is just not a universally accepted idea. And this is because the medical community is run by politics and money as much as truth. They believed for a long time that removing a woman's uterus would cure hysteria. Uh ...no.

I have heard people wonder if effectiveness is dose to body weight dependent. I don't think it is. Have read nothing to indicate that it is. Nothing. Some people have worried that taking a lower dose will result in Tamoxifen resistant cancer cells, like not taking all your antibiotics can develop drug resistant super germs. I have read nothing, NOTHING to support this idea. Tamoxifen works on cells to starve them, not fight them. I do not think it has the same action as an antibiotic so I do not believe that we can create cancer resistant super cells with lower doses.

I did read that Tamoxifen floods the system and then we want to maintain that saturation in our bodies. Some trials dosed people with a 20mg tablet to start, then cut it back to 15, 5 and 1 mg for the rest of the trial. It seems that the level of Tamoxifen remains effectively high enough even on these lower dose tablets.

What I did (remember this is only day 2) was take a 20mg tablet to start and then took half a pill (10 mg) this morning. My plan is to continue doing this. I am also thinking about taking a 20mg tablet once a week followed by 10mg for the rest of the week. At some point I will inform my oncologist. If he blows a gasket he will have to prove to me what I am doing is NOT going to work. Which he won't be able to do. Because we just don't know.

I have decided to go this route because it is the middle ground for me. I have read enough here and elsewhere to know that women who have the same diagnosis as me, taken all the same treatments, taken the 20mg tablets, and then STILL GET CANCER AGAIN which is the ultimate kick in the hoo-hoo. I know myself well enough to know that if 20mg a day makes me feel like shit I won't 'dial it back', I will quit altogether. So if I want any benefit at all from this drug, it has to never give me any trouble. Period. Trying the 20mg dose followed by 10mg daily is my way of attempting to get some benefit while avoiding the side effects that will make me throw in the towel.

I am still whacked due to radiation that just ended a week ago. My armpit feels like someone is using a blowtorch on it. I feel like the last 6 months of my life have been taken away and each day that I have left has been permanently altered by Cancer photo- bombing every upcoming life moment, every thought, every cough and ache, every birthday and anniversary. I do not believe there is a cure, I believe there is only postponement and how crappy do I want to feel in the meantime? I respect that these decisions are not for anyone but me. I hope I'm making the right choice but the truth is that we will never know. There is no clear right choice. Not from my perspective anyway.

Agostine

Hello anyone I am a newbie and still don't know how to do things around here. I have read your opinion about Tamoxifen 10mg Vs 20mg.

I am not so sure how to start it. I only read some of the side effects of Tamoxifen and I ponder a lot ..🤓

People say that for some 10mg is enough other go for the 20mg because that is the approved clinical procedure.

Perhaps is not the weight of the person but I think the stage of the cancer someone has....

MARIONSGIRL

I had no hot flashes or any symptoms during menopause but since I started Aromasin and now Tamoxifen, the hot flashes have been a daily occurence.