Tamoxifen and pre existing endometriosis and fibroids

Hello. I’m new to the forum and was diagnosed with ER+ BC Middle of May this year. I’m currently waiting to have a mastectomy but have serious concerns regarding the hormone therapy I’m going to need due to my pre-existing stage 3/4 endometreosis and large fibroid. Is there anyone out there who has been in a similar position and, if so, what did you do please? I could opt for hysterectomy but this is another large operation to undergo and would not be without extra risk for me due to the afore mentioned conditions. Also it would put me in immediate and sudden menopause on top of the side effects of hormone therapy. I’m currently aged 50.

My mother died from breast cancer at the age of 45. I was refused gene testing 15 years ago when I tried to have it done but have been referred again and hope this time I will be allowed to have the test. The results might help me with my decision.

I feel I could cope with the BC diagnosis were it not for the added complications and unknowns of my gynae issues in combination with the BC treatment.

I’d be really grateful if there is anyone out there who has faced similar issues and might be able to offer any advice or help please?

Many thanks.

Hi Faith50


I’m sorry to hear you are worrying about this, all decisions are hard,  I worried about starting hormone therapy and decided to take one treatment at a time.  I started zoladex on wed and the leaflet says it is also used to treat fiboids and endometriosis. It also says that after 2 weeks I will have the hormone level of someone who has had the menopause.  This is terrifying me. The decision to take hormone therapy was my most difficult one.  I agonised over it, asked for advice from team and read everything.


I asked my oncologist to run the figures through their computer program,  based on my details and my specific cancer. The benefit was quite a small percentage and I did think about not taking the treatment,  then I was reminded by a lady on here that every percent is a real woman who didn’t make it, so here I am, if you like I can let you know how it is.


on your other topic I had a hysterectomy nine years ago at 41 and it was the best thing I ever did. After being told for years the pain and heavy periods I had complained to my doctor about I discovered I had 13 fibroids, the biggest was 8cm I also has endometriosis.  It’s a big op and you need to be strong for it, but the delight of no pain was great, however I fought hard to keep my ovaries,  I just didn’t want the menopause. That’s a decision I regret now.


You have the choice not to take hormone therapy, my oncologist had no problem waiting until I was ready.


ask for as much information you need to make a decision you can live with. 


take care




Hi Keeks

Many thanks for your reply. I’m not surprised you’re worrying about the effects of zoladex. This is one of the options that has been mentioned for me but haven’t properly had the consultation regarding hormone therapy yet as I’m currently waiting for mastectomy.

I was offered hysterectomy with removal of ovaries and HRT 5 years ago. The operation was higher risk for me due to adhesions on bowel from the endometreosis. I declined not least because I didn’t want to go on HRT because my mum died from breast cancer! Well here I am with BC anyway! And now I have the added complication of not knowing what the effects of the hormone therapy will be.

I wish you well with the zoladex and would be grateful to hear how you get on if you have time to post.

Best wishes and many thanks for your reply.



I was diagnosed with fibroids 6 months before BC aged 42, I had a mastectomy but did not need chemo or radiotherapy just hormone therapy. I was started on Tamoxifen but was still having problems with fibroids including pressure on bladder. I was offered a hysterectomy which i did not want so went in to hospital to have ovaries removed via keyhole surgery, unfortunately they could not locate them because the fibroids had grown so much and they thought there was also endometrios so had to have a hysterectomy. I had a bad time during surgery due to the size of the fibroids ( lost a lot of blood) and there was some endometrios. I spent about 10 days in hospital and about 12 weeks off work. I have been left with slight bladder issue ( need to go often), but tablets have helped this.


I was then switched to Exemestane(aromasin,only used if you have been through menopause). I did have some side effects to start with but now i just feel tired a lot of the time and some vaginal dryness.


There may be something else they can suggest for you, If you have been allocated a breast care nurse they may be able to give you more information about the different hormone treatments available.


Sending lots of hugs


Hello.  I’m hoping someone out there has been in the same predicament as I find myself in at this moment.  I am 46, pre-menopausal, had a double-mastectomy in January, have been through chemo and now radiation, and am supposed to start Tamoxifen afterwards.  My predicament is this:  I have severe, Stage IV endometriosis, and have had it for a couple decades.  I’ve read that Tamoxifen can lead to endometrial cancer.  Since my endometrial cells are scattered throughout my abdominal cavity, I’m concerned about the Tamoxifen leading to cancer on my internal organs.    Has anyone else been in the same predicament?  Please help.  I’ve talked to my OB/GYN, and he said that he can understand my dilemma, and that my question is a very valid one, but he doesn’t know the answer.

Hi trishap


the decision we make are not easy ones. 


I have read on here about ladies having hysterectomys after being on tamoxifen because of the effect it can have on the lining of the womb. And if you have endometriosis then I wouldn’t be keen either.


I am also pre menopausal and when I got the results of my surgery the surgeon explained why tamoxifen was the best hormone therapy for me, how it worked etc. Then said I couldn’t take it due to a previous blood clot. he said the team were advising zoladex and letrazole but it was up to me.


I postponed my decision until my rads were finished and asked the oncologist to run all my stats through their computer. Based on my personal cancer details he gave me the figures for tamoxifen,  letrozole, and no hormone therapy. 


Then I was given the time to make up my own mind. Yes tamoxifen had slightly better results but it is not the only option. You have very valid concerns but there are choices and you have to live with them. Your breast care nurse might be able to give you your figures but if not I would speak to your oncologist to explore other hormone therapy treatments.


I hope they  can help you with your decision. 


Take care