Anyone taking Tamoxifen and keeping their Mirena IUD?

Ladyofthelake

I just started taking Tamoxifen last week. I'm am currently on my fourth Mirena (hormonal) IUD, have been using them for the last 20 or so years without issues. When I asked my oncologist if I needed to have my current one removed, she said she had no preference, one way or the other. I've seen many posts where it seems to be an automatic thing to have them removed. I know on the small print for the IUD that it is contraindicated for breast cancer, but that seems to be in relation to new patients. It's not so clear on whether it should be removed for existing patients. There is some protection for endometrial cancer from keeping the IUD, but what I don't know is if it also affects the efficacy of the Tamoxifen and increases the chances of breast cancer reoccurrence. I have an appointment with my gyn coming up, and will look for her input. Was just wondering if anyone else has kept theirs, or alternatively have been told they should have it removed?

Heather2018

I'm 41, just started Tamoxifen. My oncologist recommended switching from my copper IUD to hormonal. I'm currently exploring this as an option. Apparently, mirena can help guard against thickening of the uterine lining.

Salamandra

I kept my Liletta (hormonal IUD very similar to Mirena).

My doctors all had a knee jerk reaction against keeping it. But when I pushed them, they admitted it was based on the principle of excluding as much exogenous hormones as possible, rather than on solid evidence specifically on progestin IUDs.

I did a bunch of research myself and from what I found, there is only one study that shows increased risk of recurrence with the Mirena, and it is not conclusive and was criticized for the methodology. Even that study found that any increased risk of breast cancer recurrence was actually smaller than any decreased risk of ovarian and uterine cancer.

In the end, my medical oncologist spoke with a gynecological oncologist who confirmed that the Liletta would not badly interact with the tamoxifen (blood clots), and said that she would just make a note in my file that I had been counseled about removing the IUD and had chosen to keep it.

My impression is that doctors don't really yet understand the role of progesterone (and synthetic progestin) in ER+/PR+ cancers, and treating it exactly the same way as estrogen (minimize minimize minimize) is not validated by the science. Some new research actually suggests that for ER+/PR+ cancer, the progesterone acts as an inhibitor to the growth based on estrogen, and that might explain why women with ER+/PR+ have statistically somewhat better outcomes than ER+/PR-.

To me, your MO has the right idea.

Ladyofthelake

Thank you. Putting my thoughts out there, and your responses have really helped me formulate a decision. With a real lack of evidence to show progestin IUDs are detrimental when taking Tamoxifen, I can see why my MO has left it up to me.

I am 50, this was always going to be my last IUD. The plan was to keep it until I made it through menopause. However, it hasn't been as effective as my previous ones. I still have monthly bleeding, which never happened with the others. This suggests to my layman mind that the endometrium is still building up each month, so how much protection is it really giving me? I'm certainly not getting the advantage of no monthly periods any more. So I'm leaning toward having mine removed. At my age, I don't feel it's necessarily worth the fight anymore. Thanks again.

scoop

Salamandra, do you have a link to any of the research? I have been scouring the web for information to present to my MO. She originally said I could keep a progestin-only IUD, but when I called in to double-check, she said she had found a study saying to take it out. I did read that study, but as you mentioned, it is questionable at best.

I am planning to keep my Mirena based on what I currently know. Most research I find for the benefits of it, preventing endometrial side effects of tamoxifen, are applicable to post-menopausal women (I'm 38). My assumption is there would still be benefits to me. Plus I don't want the terrible side effects of the copper IUD while I'm dealing with everything else.

Thanks!

Salamandra

Hey scoop,

I'm guessing you're seeing much of what I saw, but just in case...

These were the two articles my (gem of a ) gynecologist referred me to

• Management of gynecologic issues in women with breast cancer
• Use of the levonorgestrel-releasing intrauterine system in breast cancer patients
  
  • This one has the most alarming information for women who were using the IUD at time of diagnosis. I had actually been on about a 3 year hiatus from my IUD and had got the new one in on the same day the MD found the lump in my breast, so I thought there was a good chance I didn't fit in that category. I'm unsure of what I would have done otherwise - it's still not definitive, I don't think. (I actually saw this article after for the first time after my prior thread post here).
• Caring for the breast cancer survivor's health and wellbeing

These are the other sources I still have linked in my old bookmark

• Contraception with lenorgestrel system and risks of breast cancer
• Cancer risk in women using the levonorgestrel-releasing intrauterine system in Finland
• Levonorgestrel-releasing intrauterine system and the risk of breast cancer: A nationwide cohort study
• Does levonorgestrel-releasing intrauterine system increase breast cancer risk in peri-menopausal women? An HMO perspective
• Levonorgestrel intrauterine system (LNG-IUS) for endometrial protection in women with breast cancer taking tamoxifen to prevent recurrence

Hope this is helpful! If you found any sources missing here, could you add them? I'd love to see and also I think this could be a good resource for others going forward.

scoop

Salamandra, I think you hit on most of the ones I found. Here are a few more.

Progesterone-Only and Non-Hormonal Contraception in the Breast Cancer Survivor: Joint Review and Committee Opinion of the Society of Obstetricians and Gynaecologists of Canada and the Society of Gynecologic Oncologists of Canada

Exogenous reproductive hormone use in breast cancer survivors and previvors

Studies involving post-menopausal women:

Endometrial protection from tamoxifen-stimulated changes by a levonorgestrel-releasing intrauterine system: a randomised controlled trial

I am continuing to research. I told my MO I was keeping it for now, and I was open to any research she had. She said progestin can be converted to estrogen in the body, so she was just anti any hormones.