After-tamoxifen for breast cancer: is this breast pain “normal”?

Hello! Hope you’re doing well!

I’ve recently finished my 10+ yrs of Tamoxifen. I had a WLE, some (not all the course) chemo, radiotherapy, and then 10.5 yrs of Tamoxifen. I’m now 43 and pre-menopausal - in fact my periods didn’t stop at all, just lightened a bit.

Within a couple of weeks of finishing Tamoxifen, my non-cancer breast became painful and "bigger”, for at least 3 out of 4 weeks each month - it’s like I’m pre-menstrual almost all the time. As mentioned, I had a WLE and radiation on my cancer side, but that doesn’t seem to have the same “withdrawal”.

(I’m also heavier now than I’ve ever been and just can’t shift the weight, which is making me feel fat and miserable! But that might just be due to my age :))

Is breast swelling and pain a typical or at least not-unheard-of effect of stopping Tamox, please?

Thanks so much!

Hello numbly

It sounds like this is a difficult time for you so its understandable that you are wondering if your breast symptoms are related to stopping tamoxifen.

We are unable to say what may be causing the symptoms you describe or if they are related to you stopping tamoxifen. The manufacturers of tamoxifen do not list any withdrawal symptoms when the drug is stopped, and it can be stopped without reducing it gradually. It will take about one to two months for levels of the drug to slowly reduce in the blood stream, which is why most people will not experience any symptoms when they stop. However, there have been some isolated reports of women experiencing menopausal type symptoms. but this is thought to be rare.

The pain and swelling in your unaffected breast may be related to hormonal levels linked to your menstrual cycle but hormone fluctuations can also happen as people approach the menopause. We would suggest that you talk to your treatment team or GP about these symptoms as they may suggest ways of managing this.

You also mention that you are feeling miserable and have difficulty losing weight. We often hear from people who are experiencing a range of emotions even when their treatment has finished. Getting some support to deal with how you are feeling may be helpful at this time. Your GP or treatment team can refer you to a counsellor, psychiatrist or psychologist for help and support.

Like you, other people tell us that gaining weight and struggling to lose it can affect mood and impact their quality of life. The NHS has some good information to help people manage weight loss that may be of interest which includes a free weight loss programme and exercise videos In addition they offer a Mind Plan to help people cope with anxiety and low mood

Talking to someone who has had a similar experience can often be helpful. Our Someone Like Me service can match you with a trained volunteer who’s had a similar experience to you

Do call our helpline if you would like to talk this through or have any further questions. The helpline team have time to listen, talk things through and signpost you to more support and information if necessary. Your call will be confidential, and the number is free from UK landlines and all mobile networks. The number is 0808 800 6000, (Relay UK -prefix 18001).

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Best wishes


Breast Care Nurse

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