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  • drkaycierosen

Breast Cancer and Menopause

Updated: Feb 7

I was 44 years old when I was diagnosed with breast cancer. I was still having monthly cycles like clockwork, and while I may have had some mild hormone changes starting, for the most part everything was holding pretty steady. Then, I had my first chemo treatment on December 12th. I started my period on December 25th, right on time–but little did I know that it would be my last cycle. Sigh. Cue the insomnia. The hot flashes. The night sweats. The mood swings. All the things. So in addition to healing from chemo, radiation, and surgery, I got to also be a sweaty, exhausted, emotional mess. Once I finished all my treatment 5 months later, I started Tamoxifen, which amplified these already irritating issues.

Breast cancer, estrogen, and menopause

If you have breast cancer, your treatment is likely to impact your hormones in some way. Around 80% of breast cancers are estrogen receptor positive, and about 65% are estrogen and progesterone positive. The good news is, for women with a cancer that has not spread, the 5-year survival rate is over 98%, and is still over 90% for cancers that have spread. The other side of the coin, however, is that your treatment plan will likely include something that decreases your estrogen levels on purpose. In my case, it meant that I got to go through menopause pretty much overnight, but even if the transition isn’t this dramatic, you will likely still experience symptoms because of treatment.

If you have not gone through menopause before treatment and you have an estrogen positive tumor, there are a few things that might happen: If you do not need chemotherapy, after your primary treatment you will be recommended either tamoxifen, or an aromatase inhibitor along with a medication that will stop ovulation (which makes it so your ovaries don’t produce estrogen). For many women, this will either stop your cycles or give you menopausal symptoms or both.

For women who have gone through menopause before diagnosis, hormonal symptoms from chemotherapy, tamoxifen, and aromatase inhibitors may not be as severe. However, you may still experience them!

Chemo and your hormones

If you go through chemotherapy, this can put you into menopause before you finish treatment. In addition to this, most women who go through chemotherapy will also be given a steroid called dexamethasone that is taken before and during each chemotherapy infusion. This is done to suppress a severe and dangerous reaction to the chemo, which is important! However, this can also severely impact your adrenal health, which can in turn cause mood swings, weight gain, blood sugar issues, fatigue, insomnia, and anxiety; a magical combination along with the symptoms of menopause! Chemo can also stress your thyroid, which can cause fatigue, weight gain, and mood challenges. Once you finish treatment, you will usually then be given tamoxifen or an aromatase inhibitor, which can further amplify these symptoms.

What is causing my symptoms?

Breast cancer treatment is very stressful mentally and physically, so it can be challenging to pick out what is causing symptoms. Depression, fatigue, insomnia, and anxiety are all reasonable things to expect. However, your treatment may be amplifying or causing symptoms without you even realizing it! So it can be very helpful to understand which symptoms may be caused by your treatment so you can try to get to the bottom of your concerns:

Possible hormonal Symptoms from breast cancer treatment:

Hot flashes

Night sweats


Heart palpitations


Repetitive thoughts (“hamster wheel” brain)

Digestive disturbances

Weight changes

Possible causes of symptoms:


Adrenal “fatigue” or dysfunction

Medication–tamoxifen, anastrozole, letrozole, exemestane

Hypo- or hyperthyroidism

Low estrogen or progesterone


Figuring out the root cause

How do you know if your symptoms are hormonal? A great place to start is by testing your hormones to find out. I recommend to my patients that we start by testing estrogen and progesterone, adrenal hormones such as DHEA and cortisol, and thyroid stimulating hormone. If we don’t find what we are looking for with these, we can always dig a little deeper. Once you know what is out of balance, then we can work to find solutions to help you feel more like yourself!

Here’s to our good health!

Dr Kaycie

Up next: what can I do about menopausal symptoms?

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