Tamoxifen and uterine fibroid

I have been on Tamoxifen for a year if you have other questions I can help you with. In perimenopause I had an endometrial polyp removed but I haven’t had fibroids. Im post menopausal and I’m trying to limit my sugar and fat intake and get enough exercise. I’m really conscious about not putting on weight to try to reduce uterine cancer risk.

@triciaot thanks for your reply. I have 2-3 uterine fibroids. Want to find out if Tamoxifen will increase the size of those fibroids.

According to this study, Tamoxifen is associated with a slightly increased risk of uterine cancer and other changes.

- The effect of tamoxifen on the genital tract https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2482152/
"Tamoxifen results in a spectrum of uterine abnormalities including benign alterations such as endometrial polyps, endometrial hyperplasia, endometrial cystic atrophy, adenomyosis, and uterine fibroid growth as well as malignant transformation into endometrial carcinoma and uterine sarcoma[4–8]."

@taprep, have you discussed your concern with your oncologist? I would inquire about your personal risk factors given that you already have uterine fibroids, whether you are pre or post-menopausal, risk of breast cancer recurrence, etc. What monitoring would be required?

Thanks for your reply…I did discuss with medical oncologist and she said we will start with Tamoxifen and will do ultrasound in an year to see how if it effecting the fibroids , my gynecologist suggested to have uterus removed which I am not much in favor but if required I may have to opt for that.

I am in a very similar situation...The tamoxifen makes me have leg cramps as well vague nausea throughout the day...I am on 10 ml and at times I wish I could stop. I have had breast cancer twice...the first times in 2006...it returned about a year and a half ago..Stage one...only needed radiation this time. I had been on Femara and tamoxifen for ten years after the 2006 bout with breast cancer....it still returned, but a lesser stage.
I, too have fibroids and at times feel slight cramping...its a tough call! My gynocologist has made the same suggestion as yours ...I opted out as well. Although, a hysterectomy can be done arthroscopiclly..its still a big surgery!

I was diagnosed with breast cancer 2/23/22 at the age of 47 and I truly wish that both my oncologist and gynecologist told me to get a transvaginal ultrasound prior to going on Tamoxifen so I would have had a baseline to compare. I have been on 20mg of Tamoxifen for 1.5 years along with monthly Zoladex injections (@ a year). I am chemically induced into having no periods, but I am nowhere near going into menopause based upon recent bloodwork. My uterine lining continues to thicken yet no shedding. My annual gyno check up in late fall revealed a thickened endometrial lining and polyp. I started bleeding and had to have a D&C and polypectomy right before Christmas.

I too have gone back and forth about getting a hysterectomy and oophorectomy as my uterine lining thickening will continue to pose as an issue until I have reached menopause. Everyone reacts differently to Tamoxifen; my body just has a lot of issues with it in addition to the uterine side effects. Tamoxifen has estrogenic effects on the uterus and anti-estrogenic effects in the rest of the body. It is very confusing and I had to find out about it reading medical journals and recent NIH studies. Have frank conversations with your gynecologist and oncologist and do your own research to come to a fully informed decision for what is best for you and your body. Best wishes and hang in there!

I am 54 and have just been put on Tamoxifen. I also have a couple of fibroids. Since I am in the transition phase (my period stopped last July but then all of sudden returned a few days before my double mastectomy), my medical oncologist said that Tamoxifen is the only option for me at this time. I plan to have an ultrasound soon so that a comparison can be done a year later. My medical oncologist said I can potentially switch to a different medicine once it is determined that I have entered menopause. There are so many uncertainties.