How do you find the anti-estrogen therapy that's right for you?

There are multiple types of endocrine therapy with different actions. Everyone reacts a little differently to these, but many women can switch to another one after a little break and do much better. Some women have to try a few to find the best fit. Exemestane is one of the drugs I seem to see more women tolerating. Please don’t give up too easy if you believe it to be of benefit in fighting against a recurrence, there are many choices out there.
Are planning a break before starting the new drug, just to be sure you are giving a try without residual awfulness from the anastrazole?

Hi @mf915611, I'd like to add my welcome. I hope you don't mind, but I adjusted the title of the discussion you started to reflect the question many women have about anti-estrogen therapy for hormone receptor-positive breast cancer.

The 3 main types of anti-estrogen therapies include:
- aromatase inhibitors
- selective estrogen receptor modulators (SERMs)
- estrogen receptor downregulators (ERDs)

I'd like to bring in a few more members like @bluebird70 @lisman1408 @roch @texasduchess @char81 @sparklegram @trixie1313 and others into this discussion to share their experiences. Some have switched from one aromatase inhibitor to another or from one type of therapy to another. Others have been able to stick with the original therapy prescribed.

There are side effects listed with all the options, but everyone is different. You may have side effects where someone else has few or none. Where you might have symptoms that negatively affect your quality of life with anastrozole, it may be different with exemestane. I let the others weigh in.

Do you think you'll try exemestane?

Hi everyone
I’m in month 13 of aromatase inhibitor treatment- diagnosed in Nov 2020 with IDC stage 2 A, grade 1, clear nodes, huge margins after partial mastectomy and reconstruction. No chemo. No rads and Oncotype was 12.
I started on Letrozole - within 3 months had small joint pain in hands and feet and some neuropathy. I stuck it out for 6 months, then took a 3 week break and started Exemestane. Within 3 months right back at the joint pain, neuropathy and developed a tendon contracture in right hand. So another 3 week break. I definitely feel less symptomatic with no hand pain when off the AI. My Onc wants me to start Tamoxifen- so, I got a second opinion at major Boston hospital. He said - “try anastrozole … some women find trying a third AI works” … if not, I will try Tamoxifen but I do worry about major side effects!
I really really want to stay on this treatment! I am 69 y/o - walking, yoga and staying active and positive are a huge help for me- I am an RN case manager do I research a lot (too much probably!)
I will let you know how it goes!
Best wishes to all , these are tough decisions 💕

I tried Anastrozole and I find it builds up in my system after 2 months. The side effects make me mean and depressed. I fight with family members and have made my mom cry. I went off of it for the second time. Going to try something else. Good luck with Anastrozole

I tried generic anastrazole and had trouble with fillers before I even did more than a week. I then tried generic letrozole. I ended up with brand name Femara (letrozole). My doc also said it would be fine to take alternate days, if that helped with side effects, but mine were tolerable and I stuck to daily.

The Femara insert contains a study that showed that 20% of the prescribed dose is effective so it should be okay to do alternate days, considering the half life of the drug and that 20% figure (I am speculating based on their own insert and my doc's approval of alternate days).

Here is more info on letrozole, which probably applies to others.
"Letrozole’s terminal elimination half-life is about 2 days and steady-state plasma concentration after daily 2.5 mg dosing is reached in 2-6 weeks."

So steady state plasma concentration takes awhile and that may explain why some are having more side effects after that period of time. Also, to me, it makes sense that 1) side effects might change over time with a hormonal med and 2) if we stick it out the body MIGHT adjust and stabilize....I have no studies on that but that was my experience and it makes sense.

Thanks - I appreciate the clarification between the 3 types of anti-estrogen therapies. I'm wondering how oncologists decide which combinations to use (it seems these drugs are always given in combo?). It obviously has something to do with the cancer diagnosis, and also with how the drugs are tolerated. But my oncologist is presenting my regime as a given and we never talk about drug combination options. I'm BC mets, stage 4 for 1 year now. Was on Ibrance/Letrozole and when it stopped working after 7 mos went to Faslodex (injected)/Afinitor. Thanks

The combinations are different when fighting metastatic as opposed to prevention of recurrence. There are a lot more choices for recurrence prevention, and typically just one drug is prescribed.
I still find that all the information on drug types is helpful. I have asked my doctor, “well what about this, can we try it?” Sometimes yes, sometimes not really, but always worth the conversation.
Are you comfortable enough to have these conversations with your doctor?

I was also on Anastrazole and the side affects were so bad my encologist changed me to Exemestane. The bone pain is better but I understand what you said about being mean. I fly off the handle and that is totally not my usual personality. Good luck to you. Maybe our bodies will adjust soon!! I am afraid to not take it. Mine is estrogen fed stage 1 so I feel blessed, just hate the drugs!

@adanab in case you missed it, I answered your question about how treatment decisions are determined in this discussion: https://connect.mayoclinic.org/comment/704663/

I posted to another blog "What problems have you had with Tamoxifen?" on 4/07/2022 re my experience and side effects with that drug (DVT and uterine cancer). I had a hysterectomy and was put on Aromasin/exemestane (after all, I was now post-menopausal). I stayed on that for another 5 years until my oncologist said no further benefit would come from taking it any longer. I did NOT experience hair loss, bone pain, stomach pain, moods, etc. The only real problem I had on Aromasin was that from the VERY FIRST dose, I would "urp, urp, urp" all night long after going to bed—no acid reflux, or burning in the throat, just "urp." Careful reading of the teeny print on the multi-page drug info sheet that came with the Aromasin did show “dyspepsia” as a possible side effect. That side effect went away about three months after discontinuing Aromasin.