Why does hormone therapy end?

I think this is an excellent question and I would love to know the answer too!

I've been wondering the same thing.  I have another year to go on Femara and as much as I hate the side effects, I'm so afraid to stop taking it.  It's my security blanket.  

gemini4:

I am so glad you posted this question.  I hope someone with really good answers post.  I personally hate taking tamoxifen-  I am counting down the days to year 5 (1/2 to go).  I hope there is no more treatment after that.  I feel old already (45) from the SE of tamoxifen.  But I am absolutely curious about the next step....

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)61963-1/abstract

http://am.asco.org/extending-adjuvant-tamoxifen-reduces-breast-cancer-recurrence-mortality

Above are links to recent landmark studies on the use of Tamoxifen.  They are ongoing studies....

I know that now, high risk individuals are now being offered Tamoxifen as well.  I recently asked my MO if he forsees a time when more and more high risk individuals AND patients who've had breast cancers diagnoses, will be offered endocrine therapy INDEFINITELY, and he replied, "It appears that way, however, the ONLY evidence we presently have is from the ATLAS and aTTom studies to guide us."  When the ATLAS study was made public, it begged to answer the question of who EXACTLY would benefit from 10 years of Tamoxifen.  The answer is still not as concrete as some clinicians and patients would like the study to be.  The bottom line is that now, those patients with ER fueled tumors now have a CHOICE of continuing Tamoxifen for 10 years.  More information can be found in the discussion following the professional version of the NCCN guidelines for breast cancer, beginning somewhere around page 100.  There you will find all of the current studies.  There are several ongoing studies, so hopefully, we will have a better understanding in the next few years where we will be heading with respect to who will benefit the most from continued endocrine therapy.

farmer....If I recall, the professional version has a red icon preceding it.  It's way more comprehensive than the patients version.  Let me look at it again and see if there is a better way to describe how to get to the professional's version....

From May 2013 Living Beyond Cancer, might help answer a few questions:

You have substantially reduced the risk of recurrence and the risk of forming a new breast cancer because you have taken 5 years of Arimidex. The current standard of care in medical oncology in the United States is to provide 5 years of aromatase inhibitors (such as Arimidex) to prevent recurrence of invasive breast cancer. Even in women who complete 5 years of therapy, there are a small number who will have a recurrence later.

At the present time, it is not clear whether taking Arimidex for longer will prevent any of those recurrences from happening. I donʼt think you are back to square one for this reason. I will acknowledge the field is confusing, because studies exist that support taking 5 additional years of an aromatase inhibitor (if you have taken 5 years of tamoxifen already), or taking 10 years of tamoxifen instead of 5 years of tamoxifen alone.

I should first clarify that two separate trials recently presented at major breast cancer meetings suggest that women who take tamoxifen for 10 years as opposed to 5 years have a lower risk of breast cancer returning. Collectively, both studies suggest that for approximately every 30 women treated for 10 years as opposed to 5, one additional woman may have her recurrence prevented. Another way to state this same information is that 29 women received treatment who would not benefit. Although the findings were considered statistically significant for survival, there were also certain harms that became more frequent with longer exposure to the drug (clots, endometrial cancer, etc.).

Although there is still interest in understanding whether 10 years’ use of drugs such as aromatase inhibitors will be better than just 5, these trials are large and still in active follow-up of participants. I doubt results will be available for many years to come. Moreover, in my personal opinion, they are unlikely to demonstrate much improvement over the studies that have been reported on the 10 years of tamoxifen use.

VR thanks! I guess I hadn't verified my email from the last time I tried. Gosh all the canned and scripted protocol makes me really feel like a number. 

I agree: good question. Please ask your doctor, but in the meantime, I can share what I remember from my research a few years ago.

I did research on this (on PubMed) before starting tamox in July 2011.  I wondered why 5 years was the recommended duration back then. (it's since been increased to 10 years). There were not many studies that compared taking tamox for different durations, but I found a couple that showed that taking tamox for 2 years was better than 1, and taking it for 5 years was better still.

My understanding is that they weigh the cost/benefit (pros and cons) to taking the drugs. My understanding is that the benefits of taking the drugs start to decline after a number of years; put another way, taking tamox for just 5 years shows benefits of risk of reduction even in the 5-10 year range. The risk of taking the drugs sometimes increase with age or duration of taking the drug.  (for example: the risk of blood clots while on tamox increases when a woman is older than 50 or past menopause).

ruth....your point is important!  When the results of ATLAS were announced, the importance of the study indicated that for many patients, the benefit of continuing Tamoxifen outweighed the risk.  While the media played it up with the message that 10 years was better than 5 years, it didn't mean that all patients needed to take it for 10 years.  Instead, it concluded that for many patients, continuing Tamoxifen could now be recommended.  What we are now seeing, just like with population based screening, there is a groundswell of agreement in medicine that more individualized decisions about screening and treatments should be discussed between clinicians and patients.  No more one size fits all!  The good news of doing these trials over decades, gives us more data.  The downside of these studies is that they are costly, long, and take decades to yield statistically significant data.  And then the question is, "How am I, personally, affected by the data?". The bottom line for me is that I look for trends in trial data.  It seems that based on the latest studies, more patients are being recommended more years of endocrine therapy.  That said, there are still many more ongoing trials that should better define who will benefit most and for what duration.  Since I was diagnosed it seems that recommendation has become a moving target.  When I was diagnosed, NCCN guidelines recommended that I should do endocrine therapy based on " 2B" evidence,which is less definitive evidence.  Since then, the NCCN guidelines for my type of cancer is more lax with now recommending I "consider" rather than making the stronger "recommendation" to do endocrine therapy.

So, will there be a day when ALL ER fueled breast cancer patients be recommended to do endocrine therapy for 10 years and beyond?  I think only time will tell.... Interesting though, Eric Topol, MD in his terrific book, The Creative Destruction of Medicine tells us that in the next one to two decades, clinical trials as we know them today should be abolished for the reasons I just explained and replaced with "N of one" trials which should yield data quickly and be less costly and with more INDIVIDUALIZED information!