How was it decided that 5 years on AI was enough?

kksmom3

I wonder how doctors settled on this arbitrary time period of 5 years? Why 5? It's been the standard of care since these drugs came out? Anyone know?

exbrnxgrl

Yes, someone on here knows and I believe has even posted the research. I won’t swear to it but I think it might be beesie. I am on an AI until it fails so this doesn’t pertain to me. Are there now recommendations to stay on them for 10 years

bcincolorado

On the main site there is info on AI here and I would recommend asking your MO if you are concerned as well. Here is where it is on this site.

https://www.breastcancer.org/treatment/hormonal/aromatase_inhibitors

I did not start on AI though myself and ended up on it after 5 y ears.

Best wishes.

ThreeTree

kksmom3 - Like you, I wonder about these things too. Perhaps Beesie will see this thread and respond. As someone said above, I think she might have the data. My problem though, is that I'm not always sure of the data they come up with either, because they seem to just rely on a study or two for some of this stuff, and it's all collective statistics of course, not individualized.

exbrnxgrl

ThreeTree,

Collective information is what makes up data. Individual anecdotes are not data and data cannot predict how an individual might do in given circumstances. If you are looking for a way to predict how a medication will effect an individual, that doesn’t exist at this time.

edwards750

My MO said 5 years was enough for me because Tamoxifen posed a possible risk of blood clots so why take the chance/risk. I had a blood clot in my leg when I was 16. They dissolved it with blood thinners and a heat lamp.

FYI I had IDC, Stage 1b, Grade 1 in 2011. I had a lumpectomy and 33 radiation treatments. My Oncotype score was 11 with an 8% chance of recurrence.

A friend who had BC too had to take Arimidex for 10 years because of a test(?) the MO prescribed in which she had a high score.

I’m glad to be off the drug although it did provide in my mind an extra insurance policy against a recurrence.

Diane

Racy

I have been on Letrozole for 10 years and am continuing. I truly believe I will have a recurrence if I cease the drug as some of my lifestyle habits are risk factors...

My doctor is happy for me to continue taking this AI as I have had no adverse effects.

Talk to your doctor and get a second opinion if you want one.

cocomo

My oncologist put me on AI medications right after surgery/chemo/radiation 9 years ago. Was told I would need to be on it for 5 years originally. At the 5 year mark, my oncologist told me, studies have shown people get better results from taking AI medications for 10 years. I took Aromasin for most of the 9 years; until it stopped working; end of July 2021. I did not have any terrible side effects on Aromasin; just thinning hair.

And, I recently learned 2nd opinions can be a great choice.

FindingOptimism

In the early 2000s, there were studies showing that 5 years of tamoxifen was significantly more effective than 2. That was when the treatment term changed. I don’t think 5 years was truly scientific but rather what was used in the studies. Similarly you now see recommendations for 7 or 10 years, but we don’t know if 6.3 would be optimal. You can see similar patterns in dosing. Dosing had been higher than 20 mg, but was decreased due to side effects and patient compliance.

kksmom3

FindingOptimism, thanks, that's the kind of info that I was looking for.

Hopeful82014

https://www.breastcancer.org/research-news/2-more-years-of-arimidex-after-hormonal-treatment-offers-same-benefits-as-5https://www.breastcancer.org/research-news/treatment-break-from-extended-femara-doesnt-affect-survival

(Sorry, the two links were pasted together and it’s hard to disconnect them on my iPad but I think it’s clear enough that you can see where to insert breaks. Or just go to the Breast Cancer Research News on the BCO site - which is a good spot to regularly check for new info.)

These are a couple of recent studies posted on the BCO research news page that you might find helpful (I know I did), particularly the first one.

Over the past few years there has been a strong push towards keeping women on endocrine therapy for7.5 to 10 years total. I’ve been told all along that I should plan on 10 years but am going to revisit that with my MO after reading the Arimedex study. (The link above is to an abstract but you can access the complete article by creating a free account at the NEJM. It’s worth reading.

SpecialK

In an understanding of why anti-hormonals, or any medication for that matter, is prescribed for a given time period it is important to also understand the FDA drug approval process. Drugs are not approved initially until they have been exhaustively trialed. In the 1980's drugs averaged 30 trials before approval, in the '90's that number doubled. Drugs are initially investigated by researchers - from drug companies and compounds in research settings - for a number of years until the approval process even starts with the FDA. Sometimes drugs developed for one purpose - such as Tamoxifen for birth control - are eventually used for another purpose, like cancer treatment. In Phase 1 of the approval process, which typically takes about a year and a half, the drug is used on healthy volunteers - usually numbering in the hundreds - and studied to determine safe dosing and effect. In Phase II, typically two years and with a larger group of volunteers, the drug is studied on a population with the target disease and researchers are looking for effectiveness and side effects. I have some firsthand knowledge of this - I participated in a Her2+ recurrence prevention vaccine Phase II trial. Whoever is conducting the testing meets with the FDA after Phase II to discuss whether to continue and what they have learned so far. In Phase III, a longer term averaging three and a half years with a significantly larger population - if there has been success in Phase II - the drug is studied with use over a more prolonged time to see if the effectiveness changes or side effects intensify when compared to data collected in Phase II. After Phase III the data goes to the FDA where there is consideration for a period of time - often 1-2 years until approval, but sometimes approval is accelerated if the drug is very promising. Tamoxifen was developed before aromatase inhibitors, and both have continued to be studied since inception. Clinicians also provide after market reporting to the FDA as their patients use approved drugs. Recommendations for prescriptive use are refined with guidelines developed by organizations like ASCO (the American Society of Clinical Oncology) and the NCCN (the National Comprehensive Cancer Network) to help practicing oncologists make the best treatment decisions for their patients. When drugs like Arimidex (anastrazole), Femara (letrozole, and Aromasin (exemestane) were developed they were compared against the established five year timeline originated for Tamoxifen. Aromatase inhibitors continue to be studied in an effort to determine if less is more, or more is more. When I was first diagnosed five years was the standard for all anti-hormonal therapy for early stage breast cancer patients. During my initial five years on aromatase inhibitors some studies were published that indicated first that Tamoxifen for 10 years was better than five, and that followed suit for aromatase inhibitors. I believe that there is now some info, referenced above, that 7 years for that class of drugs is better than five, but 10 is not superior to 7. Also a newer test, the Breast Cancer Index test by Biotheranostics, takes a genomic look at original tumor material after the patient is five years into anti-hormonal treatment, to determine whether there is a benefit to continuing beyond five years, and what the risk of recurrence is going forward. I had this test done and unfortunately the result for me was a high risk of recurrence, but a low benefit from the drugs - I fell into a category that about 1 in 10 do. As these drugs are looked at in current practice, sometimes studies are done that look at giving drugs in shorter duration. This can be done to remediate side effects, or mitigate cost. This has happened with Herceptin - looking at shorter administration periods than the currently recommended 12 month duration. In order to shorten a current guideline there must be a demonstrated non-inferiority, meaning that the drug, or time period it is taken, is comparable to the current usage. I believe lower dose Tamoxifen is being looked at, and used by some, for treatment of DCIS. Some oncologists have allowed lower dose and split dose Tamoxifen in an effort to keep their patients on the drug, versus having them discontinue altogether. Linked below is some information from the NCI regarding long term data on Tamoxifen use. I don't think we have yet arrived at truly individualized dosing/duration for breast cancer treatment modalities, but I do feel like there is incremental progress, and certainly it can be of benefit to have a collaborative relationship with one's oncologist to allow a degree of tailoring in the approach used.

https://www.cancer.gov/types/breast/research/tamoxifen-long-lasting-benefit

Here is some additional info about study of length of time and benefit for aromatase inhibitors.

https://ascopost.com/issues/march-10-2019/more-dat...

kksmom3

Thank you, SpecialK, very informative!